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## Material Information- Title:
- Evaluation of Hurricane-Resistant Single-Family Residential Structures
- Creator:
- RUSSELL, MICHAEL VINCENT
- Copyright Date:
- 2008
## Subjects- Subjects / Keywords:
- Axial stress ( jstor )
Beams ( jstor ) Bending ( jstor ) Bending moments ( jstor ) Compressive stress ( jstor ) Hurricanes ( jstor ) Roofs ( jstor ) Shear stress ( jstor ) Tensile stress ( jstor ) Trusses ( jstor ) Gulf of Mexico ( local )
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- University of Florida
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- University of Florida
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- Copyright Michael Vincent Russell. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
- Embargo Date:
- 12/1/2003
- Resource Identifier:
- 434595872 ( OCLC )
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PAGE 1 EVALUATION OF HURRICANE-RESISTANT SINGLE-FAMILY RESIDENTIAL STRUCTURES By MICHAEL VINCENT RUSSELL A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING UNIVERSITY OF FLORIDA 2003 PAGE 2 Copyright 2003 by Michael Vincent Russell PAGE 3 ACKNOWLEDGMENTS Completion of this research and thesis would not have been possible without a number of individuals. The author would like to thank Dr. Perry S. Green, Dr. Ronald A. Cook, P.E., and Dr. H.R. Hamilton, P.E., for serving on his graduate supervisory committee. In particular, gratitude is extended to Dr. Perry S. Green. Not only was a research assistantship provided by Dr. Green, but also his extensive knowledge, patience, and substantial time investment. Others deserving of thanks due to daily contributions of resources are Dr. Thomas Sputo, P.E., Brian D. Warfield, and Anne Cope. The author would also like to thank all of his close friends at the Sweeny Compound, most importantly, Grandy and Conroy. Lastly, the author would like to thank his close relatives and the Reid Family for their support and making it possible to attend school. iii PAGE 4 TABLE OF CONTENTS Page ACKNOWLEDGMENTS.................................................................................................iii LIST OF TABLES.............................................................................................................vi LIST OF FIGURES..........................................................................................................vii ABSTRACT.......................................................................................................................xi CHAPTER 1 INTRODUCTION........................................................................................................1 1.1 National Level........................................................................................................1 1.2 State Level..............................................................................................................2 1.3 National Quality Demonstration Project................................................................3 1.4 Scope of Work........................................................................................................4 2 BACKGROUND/LITERATURE REVIEW/HISTORICAL PERSPECTIVE............5 2.1 Single Family Residential Structures......................................................................5 2.2 Hurricane Effects on Structures..............................................................................7 2.3 Past and Current Research......................................................................................9 3 METHODOLOGY FOR DESIGN OF A SINGLE-FAMILY RESIDENTIAL STRUCTURE.............................................................................................................12 3.1 Design Loads........................................................................................................12 3.1.1 Gravity Loads.............................................................................................12 3.1.2 Wind Loads................................................................................................13 3.2 Description of a Residential Structure..................................................................16 3.2.1 Structural Components and Assemblies.....................................................17 3.2.2 Connections................................................................................................20 4 EVALUATION STUDY OF MERCEDES HOMES SINGLE-FAMILY RESIDENTIAL STRUCTURES................................................................................22 4.1 Evaluation Procedure............................................................................................22 4.2 Structure No. 1 â€“ Baseline Home CMU Home....................................................23 4.2.1 Structural Analysis.....................................................................................25 iv PAGE 5 4.2.2 Summary of Results...................................................................................37 4.3 Structure No. 2 â€“ CMU Home..............................................................................38 4.3.1 Structural Analysis.....................................................................................39 4.3.2 Summary of Results...................................................................................42 4.4 Structure No. 3 â€“ Concrete Home.........................................................................43 4.4.1 Structural Analysis.....................................................................................45 4.4.2 Summary of Results...................................................................................54 5 CONCLUSIONS & RECOMMENDATIONS...........................................................55 5.1 Conclusions of the Evaluation Study....................................................................55 5.2 Recommendations for Further Improvements......................................................56 5.2.1 General Recommendations.........................................................................57 5.2.2 Specific Recommendations........................................................................57 5.3 Future Research....................................................................................................59 APPENDIX A EVALUATION SUMMARY OF STRUCTURE NO. 1 BASELINE HOME..........61 B EVALUATION SUMMARY OF STRUCTURE NO. 2 IMPROVED CMU HOME..............................................................................................................86 C EVALUATION SUMMARY OF STRUCTURE NO. 3 CONCRETE HOME.......114 D ANALYSIS OF RECOMMENDED BOND BEAM...............................................133 LIST OF REFERENCES.................................................................................................139 BIOGRAPHICAL SKETCH...........................................................................................142 v PAGE 6 LIST OF TABLES Table page 4-1. ASCE 7-98 Section 2.4 ASD basic load combinations.............................................23 4-2. Shear wall stresses in the left and right elevations....................................................30 4-3. Pier analysis results of the front and back elevations................................................31 4-4. Results of multiple design checks of the interior load-bearing wall.........................34 4-5. Confidence factors of baseline home.........................................................................38 4-6. Confidence factors for structure No. 2......................................................................43 4-7. Shear wall stresses in the left, right, and back elevations..........................................51 4-8. Pier analysis results of the front elevation.................................................................51 4-9. Results of multiple design checks of the interior load-bearing walls........................53 4-10. Confidence factors for structure No. 3....................................................................54 A-1. Confidence factors for the truss-to-bond beam anchors...........................................82 A-2. Confidence factors for the anchors/connectors of the back trussed porch...............85 A-3. Confidence factors for the anchors/connectors of the front entry............................85 B-1. Confidence factors for the truss-to-bond beam anchors.........................................109 B-2. Confidence factors for the anchors/connectors of the back trussed porch..............112 B-3. Confidence factors for the anchors/connectors of the front entry...........................113 C-1. Confidence factors for the truss-to-bond beam anchors........................................129 C-2. Confidence factors for the anchors/connectors of the back trussed porch.............132 vi PAGE 7 LIST OF FIGURES Figure page 3-1. Effects of wind acting on the surface of a residential structure.................................14 3-2. Wind speeds used to determine the design loads for the southeastern United States (ASCE, 1998)................................................................................................15 3-3. Plan view of project structures of evaluation study...................................................17 3-4. General representation of a residential structure.......................................................19 3-5. Elevation view of a CMU wall with a bond beam and precast lintel (SBCCI, 1999)..........................................................................................................20 3-6. Various roof truss connections to CMU wall............................................................21 4-1. Plan view of structure No. 1-baseline home and structure No. 2..............................24 4-2. Maximum in-plane lateral forces due to the design wind pressure applied to the exterior CMU walls............................................................................................26 4-3. Load-moment (P-M) interaction diagrams for exterior CMU walls.........................27 4-4. Cross section view of the single course bond beam..................................................28 4-5. Structural analysis result showing deflected shape of the back wall elevation of the structure subjected to in-plane lateral and uplift loading...............................29 4-6. Shear wall designations used in the structural analysis.............................................30 4-7. Cross-section view of the composite beam: precast lintel and bond beam..............32 4-8. Elevation view of back trussed-porch and front entry...............................................33 4-9. Elevation view of the garage door and anchorage.....................................................35 4-10. Details of door and window anchorage...................................................................36 4-11. Nail size and schedule anchoring the roof sheathing..............................................37 4-12. Critical exterior CMU wall sections of structure No. 2...........................................40 vii PAGE 8 4-13. Load-moment interaction diagram for 8 wall section in the back elevation..........41 4-14. Load-moment interaction diagram for critical section in the left elevation............41 4-15. Plan view of structure No. 3....................................................................................44 4-16. Maximum in-plane lateral forces due to the design wind pressure applied to the exterior concrete walls........................................................................................46 4-17. Critical exterior concrete wall sections of structure No. 3......................................47 4-18. Load-moment interaction diagram for 12 wall section adjacent to sliding glass door in the back elevation...............................................................................48 4-19. Load-moment interaction diagram for typical wall section (per foot of wall)........48 4-20. Cross-section view of the coupling beam................................................................49 4-21. Shear designations of structure No. 3 used in the structural analysis......................50 4-22. Back trussed porch of structure No. 3.....................................................................52 5-1. Suggested reinforced concrete column to replace CMU pier....................................58 A-1. Load-moment interaction diagram for the exterior CMU walls (per foot of wall)..62 A-2. Shear wall locations in the right and left elevations along with the garage sidewall.....................................................................................................................63 A-3. Piers and coupling beams in the front and back elevations along with the garage â€œgoal postâ€................................................................................................................64 A-4. Tensile load-moment interaction diagram for pier 1 of the front elevation.............65 A-5. Tensile load-moment interaction diagram for pier 3 of the front elevation.............66 A-6. Tensile load-moment (negative) interaction diagram for coupling beams 1 and 2.........................................................................................................................67 A-7. Tensile load-moment (positive) interaction diagram for coupling beams 1 and 2.........................................................................................................................68 A-8. Tensile load-moment interaction diagram for pier 2 of the back elevation..............69 A-9. Tensile load-moment interaction diagram for pier 3 of the back elevation..............70 A-10. Tensile load-moment interaction diagram for pier 4 of the back elevation............71 A-11. Tensile load-moment interaction diagram for pier 5 of the back elevation............72 viii PAGE 9 A-12. Tensile load-moment (negative) interaction diagram for coupling beams 1 through 5..................................................................................................................73 A-13. Tensile load-moment (positive) interaction diagram for coupling beams 1 through 5..................................................................................................................74 A-14. Shaded areas approximately show the sections of bond beam that fail..................75 A-15. Location of critical lintels in the project structure.................................................77 A-16: Location of the back trussed porch, front entry, and interior load bearing wall...78 B-1. Load-moment interaction diagram for 8â€ pier in the back elevation........................87 B-2. Load-moment interaction diagram for most critical wall section in left elevation...88 B-3. Load-moment interaction diagram for 8â€ pier in the front elevation........................89 B-4. Shear wall locations in the right and left elevations along with the garage sidewall.....................................................................................................................90 B-5. Piers and coupling beams in the front and back elevations along with the garage â€œgoal postâ€................................................................................................................91 B-6. Tensile load-moment interaction diagram for pier 1 of the front elevation..............92 B-7. Tensile load-moment interaction diagram for pier 3 of the front elevation..............93 B-8. Tensile load-moment (negative) interaction diagram for coupling beams 1 and 2.........................................................................................................................94 B-9. Tensile load-moment (positive) interaction diagram for coupling beams 1 and 2.........................................................................................................................95 B-10. Tensile load-moment interaction diagram for pier 2 of the back elevation............96 B-11. Tensile load-moment interaction diagram for pier 3 of the back elevation............97 B-12. Tensile load-moment interaction diagram for pier 4 of the back elevation............98 B-13. Tensile load-moment interaction diagram for pier 5 of the back elevation............99 B-14. Tensile load-moment (negative) interaction diagram for coupling beams 1 through 5................................................................................................................100 B-15. Tensile load-moment (positive) interaction diagram for coupling beams 1 through 5................................................................................................................101 B-16. Shaded areas approximately show the sections of bond beam that fail................102 ix PAGE 10 B-17. Location of critical lintels in the project structure................................................104 B-18: Location of the back trussed porch, front entry, and interior load bearing wall...105 C-1. Load-moment interaction diagram for 1â€™ section of wall in the back elevation.....115 C-2. Load-moment interaction diagram for most critical wall section (per foot of wall) in left elevation..............................................................................................116 C-3. Shear wall locations in the back, right, and left elevations along with the garage back bedroom sidewalls.........................................................................................117 C-4. Piers and coupling beams in the front elevation along with the garage â€œgoal postâ€..............................................................................................................119 C-5. Tensile load-moment interaction diagram for coupling beam 1.............................120 C-6. Tensile load-moment interaction diagram for pier 1 of the front elevation............121 C-7. Tensile load-moment interaction diagram for pier 2 of the front elevation............122 C-8. Tensile load-moment interaction diagram for pier 3 of the front elevation............123 C-9. Tensile load-moment (negative) interaction diagram for coupling beams 1 and 2.......................................................................................................................124 C-10. Location of critical coupling beams in the project structure.................................125 C-11. Location of the back trussed porch and interior load bearing wall.......................126 x PAGE 11 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Engineering EVALUATION OF HURRICANE-RESISTANT SINGLE-FAMILY RESIDENTIAL STRUCTURES By Michael Vincent Russell August 2003 Chair: Perry S. Green, PhD Major Department: Civil and Coastal Engineering One of the goals of the evaluation study conducted for Phase II of the National Quality Demonstration Project was to aid in the design of an improved hurricane-resistant demonstration home that would be capable of withstanding 140-150 mph hurricane force winds. The NQDP is a three-phase project with the goal to establish a framework for an improved hurricane-resistant single-family residential home that qualifies for a reduction in insurance premiums and/or a preferred mortgage rate. The overall goal to be achieved by Phase II of the project was to determine solutions for hazard mitigation and quality assurance that will be used in the design of a new prototype demonstration home. The scope of work involved an evaluation study of three existing residential structures, which will be used in the design and structural analysis of the improved hurricane resistant home. Structure No. 1 was considered the Baseline Home and consisted of CMU construction. Structure No. 2 was considered the improved CMU home and Structure No. 3 was a monolithically place reinforced concrete home. xi PAGE 12 Structural components were analyzed, and then using those results, the critical components or â€œweak linksâ€ that existed in each house were identified. General and specific recommendations for improvement were given for each of the critical component identified. One such recommendation was the use of a 16 double course bond beam in the exterior CMU walls. One of the main conclusions of the study was that further research be conducted based on the suggested structural recommendations, such as different design approaches and the economics of construction. This research along with the structural improvements that have been recommended will allow the design and construction of this home to commence. xii PAGE 13 CHAPTER 1 INTRODUCTION Due to many residential developments being constructed every year in the hurricane-prone regions of Florida, the probability of sustaining property damage as a direct result of a hurricane is very high. Damage mitigation of residential structures subjected to severe wind events, such as hurricanes, is one of the highest priorities at the state and national levels. It was estimated that more than $15 billion in insured property damage was the direct result of Hurricane Andrew hitting South Florida on August 24, 1992 (DIIO, 2001), with a majority of the damage observed in residential structures. Building performance studies have concluded that partial or ultimate failure of residential structures, due to hurricane force winds, was mainly due to the lack of a load transfer path between the structural components (FEMA, 1993; Keith & Rose, 1994; Suaris & Khan, 1995; Zollo, 1993). The two main reasons for this lack of load transfer path were either inadequate design or poor quality of construction. The ultimate goal and objectives of state and national officials, engineers, architects, home builders, and insurance agencies is to prevent overall monetary losses in the design and construction of residential structures to resist hurricane force winds. 1.1 National Level Many national organizations are responsible for the damage mitigation and quality assurance of residential structures. The Federal Emergency Management Agency (FEMA), United States Department of Housing and Urban Development (HUD), and the American Society of Civil Engineers (ASCE) are some of most active participants at the 1 PAGE 14 2 national level. An objective of these organizations is to reduce the losses that could occur from a natural hazard such as a hurricane. One of the most recent initiatives involving ASCE, HUD, the Institute for Business & Home Safety (IBHS), and the United States Geological Survey (USGS) involves identifying the natural hazard that posses the highest threat to buildings and to establish solutions that would prevent these losses (IBHS, 2001). Atop that list is hurricanes and other severe wind events. Whenever extensive structural damage or failure occurs due to either natural or man-made hazards, FEMA is usually the first-response organization responsible for the initial investigation of collapse or cause of damage. In 1993, FEMA and the Federal Insurance Administration (FIA) responded to the devastation caused by Hurricane Andrew by conducting a building performance study of the structures that were in Andrewâ€™s direct path (FEMA, 1993). 1.2 State Level The Florida Building Commission of the Florida Department of Community Affairs (FDCA) is responsible for implementing and enforcing the Florida Building Code (FBC) (SBCCI, 2001), the governing building code in the state. Prior to March 2002, multiple building codes used throughout the state were administered and enforced at the discretion of more than 400 local jurisdictions and state agencies. It was later determined in the aftermath of Hurricane Andrew that the resulting damage was not due to a weakness in the building codes, but was due to the inability of building officials to enforce and the construction industry to conform to the confusing system of multiple codes and administrative processes (FDCA 2003). The recently adopted 2001 FBC is a single statewide building code that went into effect March 1, 2002, for the entire state of Florida. This single statewide code is the stateâ€™s solution to reduce the confusion that PAGE 15 3 may occur between governing officials and the industryâ€™s lack of conformance during the construction phase. The Florida Department of Insurance (FDOI) is also highly involved in wind damage mitigation studies for residential structures. One of their objectives is to accurately predict insurance losses, due to hurricanes, for homes throughout the state and to determine solutions to reduce these losses. These losses are based on building materials and the location of the structure within the state. These damage prediction models will be used along with post damage investigations to estimate the cost of insurance premiums (Cope, Gurley, Pinelli, & Hamid, 2003). 1.3 National Quality Demonstration Project The National Quality Demonstration Project (NQDP) is a three-phase project with the goal to establish a framework for a hurricane-resistant single-family residential home that qualifies for a reduction in insurance premiums and/or a preferred mortgage rate. FEMA and HUD are the primary sponsors of the project with the University of Florida, Gainesville, FL, Mercedes Homes, Melbourne, FL, and Steven Winter Associates, Norwalk, CT, conducting the research. The three phases of the NQDP consist of: 1) Work Plan Development, 2) Structural Analysis and Design of Demonstration Home, 3) Construction, Evaluation, and Outreach. All work leading up to and including this thesis involves Phase II of the NQDP. The overall goal to be achieved by Phase II of the project is to determine solutions for hazard mitigation and quality assurance that will be used in the design of an improved hurricane-resistant demonstration home. PAGE 16 4 1.4 Scope of Work The scope of work conducted involves an evaluation study of existing residential structures, which will aid in the design and structural analysis of the demonstration home. The goal of this study was to evaluate and compare the resistance of residential structures to hurricane-force winds and to report all findings to the NQDP participants. Chapters 2 and 3 present the background/historical perspective and the design methodology used for the evaluation study. Chapter 4 presents, in detail, all analyses and design checks conducted. Structural components were analyzed and then using those results, the critical components or â€œweak linksâ€ that existed in each house were identified. The components selected for analysis are as follows: Exterior Walls Reinforced Bond Beam Precast Lintels Interior Load Bearing Walls Back Trussed Porch/Front Entry Doors/Windows/Garage Door Anchorage Roof Sheathing Truss Anchors/Connectors After determining the critical components, recommendations for design improvements and/or further research were given and can be found in Chapter 5. Three house designs, having similar model layouts, were selected for this evaluation. All are one-story houses with four bedrooms, have two car garages extending off the main living quarters, and are approximately 2500 square feet in plan. Complete construction plans for all three house designs were provided by Mercedes Homes and the pre-engineered roof truss packages showing the support reactions of the trusses were provided by Space Coast Truss, Inc. PAGE 17 CHAPTER 2 BACKGROUND/LITERATURE REVIEW/HISTORICAL PERSPECTIVE 2.1 Single Family Residential Structures In the state of Florida, the number of residential structures has grown substantially over the years. Much of this growth has occurred in the coastal areas that are subjected to high winds caused by hurricanes, such as the Southeast and Gulf Coasts of the U.S. The population of the coastal Southeast, Virginia to South Florida, was approximately 8 million people in 1960 and the number is expected to increase to almost 23 million by 2015; a 188% population increase (NOAA, 2003). Likewise, the population along the coastline of the Gulf of Mexico is predicted to increase from 8 million in 1960 to an expected 22 million in 2015. Nearly, 40% of all new housing construction along coastlines of the U.S. is either in Florida or California and almost two-thirds of the residential developments being constructed today along the coasts of the U.S. are single-family homes. Both economic and social concerns are the reasons for this dramatic growth. Floridaâ€™s climate and low cost of living draws in new families and retirees every year. This growth near the coastlines of hurricane prone regions has brought about concerns of the high probability of large-scale damage in the event of a natural disaster occurring, such as a hurricane. The type of house constructed in these regions varies from concrete block to light wood-framed construction. The materials from which these homes are constructed have not changed over the years, however, the governing design provisions of the building codes have evolved greatly. The prescriptive wind design loads required by current 5 PAGE 18 6 building codes are more representative of the actual loads acting on a structure than those previously used due to the advances in wind tunnel studies. The wind loading requirements of the American National Standards Institute (ANSI) Standard A58.1, first introduced in 1972, was the result of the advancement of analytical techniques to manage randomly applied wind loads and boundary layer wind technologies (TTU, 1988). Today, this standard is known as ASCE 7 Minimum Design Loads for Building and Other Structures (ASCE, 1998). Revisions to the wind loading requirements in this document have been made over the years leading to more accurate wind design loads. Several â€œdeemed-to-complyâ€ standards also are available specifically for aiding in the design of residential structures to resist hurricane force winds. To date, one of the most current standards dealing with this is the Standard for Hurricane Resistant Residential Construction SSTD 10-99 (SBCCI, 1999). The minimum design requirements given in this document are based on the provisions of Section 1606 of the Standard Building Code, now the 1 st Edition Florida Building Code, and are intended to ensure the structural integrity of a structure subjected to hurricane force winds of 74 mph to over 155 mph. Hurricane resistant construction was not only a concern after Hurricane Andrew in 1992; similar documents also existed back to the 1930â€™s addressing this issue. The National Board of Fire Underwriterâ€™s published a document suggesting special requirements for hurricane resistant construction that conformed to the 1937 Building Code of the City of Miami, FL (NBFU, 1939). The U.S. Forest Service also published a similar document in the 1965, which addressed the hurricane resistance of residential PAGE 19 7 construction located specifically in the Southeast and Gulf Coast of the United States (Anderson & Smith, 1965). 2.2 Hurricane Effects on Structures The wind pressures acting on a structure that are induced by the effects of a hurricane can be substantial. Over the years, hurricanes have caused a large amount of structural damage to residential dwellings. The destruction caused by Hurricane Andrew in 1992 to residential dwellings was not unfamiliar. Similar structural weaknesses were also exposed after previous hurricanes such as Betsy in 1965, Camille in 1969, and Hugo in 1989. The significance of Hurricane Andrew was the appearance of a more widespread and overwhelming destruction to major housing developments, which had taken place over the years (Imbert, Drakes, & Prevatt, 1994). Multiple building performance studies conducted after Hurricane Andrew revealed many similar types of structural failures in single-family residential masonry structures. The heavier and stiffer concrete block masonry homes were more forgiving than the wood framed houses, but damage still occurred. Much of the damage observed was caused by extreme wind pressure and water damage within the interior of the structure due to breaching of the building envelope. Loss of roofing material led not only to water damage in the interior but also may have caused instability of the exterior walls depending on the severity of the roof failure. In many cases, no vertical steel reinforcement was found in the walls that may have provided uplift anchorage for the tie beams. This resulted in failures where the entire roof along with the tie beam was lifted off the building. The now unsupported, un-reinforced walls eventually collapsed when subjected to continued lateral wind loading (Zollo, 1993). It was observed that most collapsed homes had masonry block cells filled PAGE 20 8 with grout but with no reinforcing bars where tie-downs where supposed to be located. In some cases, un-grouted cells were found containing vertical reinforcement (Suaris & Khan, 1995; Zollo, 1993). A common failure observed in all different types of homes was the loss of roofing material such as roof covering and sheathing. The loss of the roof covering or shingles due to Hurricane Andrew was widespread throughout Dade County, FL. Typically, this did not lead to any structural damage, but did allow the penetration of water into the building envelope. It was determined that the majority of the roof sheathing that was lost was due to inadequate attachment to the roof trusses. Erratic fastening patterns were commonly observed and in many cases the nails were not anchored into the truss framing below the sheathing (FEMA, 1993; Keith & Rose, 1994). Failure of building envelope openings such as windows, doors, and garage doors were also observed. Unprotected windows led to glass breakage caused by wind-borne debris while many garage doors failed due to excessive deflections caused by wind suction, that led to the pullout of the glider wheels from their tracks (Suaris & Khan, 1995). The building performance studies that were conducted after Hurricane Andrew ultimately came to the same conclusion that poor quality of construction workmanship and noncompliance with the prescriptive requirements of the governing building code led to many of these failures. General recommendations made in these studies were: Improve the quality of construction Increase the knowledge and training of the workforce in use of proper construction techniques. Increase inspector supervision Increase participation from a licensed design professional during construction inspection (FEMA, 1993). PAGE 21 9 Many specific details were also suggested concerning individual structural components such as the roof framing system, exterior wall openings, and masonry walls (FEMA, 1993; Zollo, 1993). Quality control and inspection of the construction of the roof cladding and roof framing system Design of more aerodynamic building shapes; use of hip roofs other than gable ends Specifications for garage doors should have a factor of safety of at least 2.5 Design and construction of masonry walls must be ensured through code compliance Masonry walls with continuous tie beams/bond beams should be engineered and constructed to support the required loading Provide adequate connections and lateral support for gable trusses Investigate the use of masonry bond beams and vertical wall reinforcement, per SBCCI, as an alternative to the currently prescribed South Florida Building Code wall reinforcement 2.3 Past and Current Research To date, much of the published literature involving the hurricane resistance of single-family residential structures expresses concerns and emphasizes that solutions are needed (Carter & Nichols, 1994; McAllister & Crandell, 2002; Imbert, Drakes, & Prevatt, 1994). These researchers have concluded that the major insufficiencies in the design of single-family residential structures is the inadequacy of connections that provide continuous load paths to resist lateral and uplift loads and the breaching of the building envelope. It is also the consensus of these researchers that the lack of formal engineering and inspection is what leads to these insufficiencies. A study conducted by the St. Petersburg Times reviewed randomly selected â€œsealedâ€ engineered drawings of residential structures. It was determined by the investigator of the study that 90% of the PAGE 22 10 designs proved inadequate relative to the wind-load requirements of the local building codes. It was also determined that most designs were based on â€œengineering judgmentâ€ and few, if any, backup calculations were performed (Minor, 2002). The perception of many researchers that single-family residential structures are considered to be â€œnon-engineeredâ€ structures seems to hold true to this day. Research studies have been conducted on single-family residential structures as a whole along with studies of individual components such as masonry walls and roof systems. Computer simulations and modeling has also been used in the past. Vickery, Twisdale, and Young (2002) used simulation models to replicate characteristics and frequencies of hurricanes of various strengths at the location of a model home. A wind load model was used to estimate the induced wind pressures and windborne debris. Based on a building component resistance model, the vulnerability of the home was determined. Research involving the roof diaphragm has also been conducted. Mizzell (1994) at Clemson University focused on sheathing for residential roofs. The main objective of the study was to determine what parameters, such as panel size and thickness, fastener type and size, fastener schedule, construction procedures, etc., most influenced the uplift capacity of the roof sheathing and to what degree. The author stated that at the time of the study, roof fastener schedules were based on shear and deflection tests along with the withdrawal capacity of a fastener and that very little testing had been done to determine the resistance of roof sheathing exposed to an applied uplift pressure. The results of the project concluded that the governing parameters considering uplift capacity were construction quality and the large variability of wood. The study also suggested that the quality control in workmanship be improved. PAGE 23 11 One analytical study conducted on roof system components was to determine the reliability of light-frame construction subjected to high-wind uplift (Rosowsky & Cheng, 1996). As previously concluded from the hurricane post-damage studies, maintaining the integrity of the roof system will ultimately minimize losses. The reliability analysis only focused on the sheathing to roof framing and the roof to wall connections. The results of the analysis confirmed that there are a relatively small number of sheathing panels and roof-to-wall connections that control the overall roof system capacity, and hence dominate the failure probability. It was determined that the critical sheathing panels are located at the edges of the roof and the critical roof-to-wall connections are located at or near a gable end. The Ten Most Wanted (IBHS, 2001) is a report of a two-day workshop, involving forty-two experts in natural disaster reduction, with the goal to search for solutions and develop recommendations and priorities for future research and development in the mitigation of damage caused by natural hazards. This panel determined that hurricanes and other severe wind events should be given the highest priority of all natural disasters. It was highly suggested that additional research and development be conducted on roofing systems, building envelopes, and structural systems of residential buildings in order to mitigate damage that might be caused in the future. PAGE 24 CHAPTER 3 METHODOLOGY FOR DESIGN OF A SINGLE-FAMILY RESIDENTIAL STRUCTURE One of a residential structureâ€™s primary functions is to provide permanent shelter for one or more persons from the outside elements. Therefore, it is important to identify and understand all aspects of a structure and how it behaves when subjected to its surrounding environment. The following methodology provides a general description of what must be considered in the design of a residential structure. This information is used in the detailed analyses that were performed as part of the evaluation study and presented in Chapter 4. 3.1 Design Loads Typically, residential structures are subjected to their own self-weight, roof live loads, wind loads, and if a flat roof is present, rain loads. Currently, all local governments in the state of Florida have adopted the 1 st Edition of the Florida Building Code (SBCCI, 2001). This code gives the minimum design loads that shall be used when analyzing and designing a residential structure. These minimum design loads are typically categorized as gravity loads and wind loads. 3.1.1 Gravity Loads Loads that act in the vertical direction (downward) are considered gravity loads. Dead load, or the self-weight of the structure, and roof live load are gravity loads. A minimum roof live load is required for design and accounts for activities that occur on the roof during construction such as workers, equipment, and temporary material storage as 12 PAGE 25 13 well as for loads that are applied to the roof after construction is complete. A roof live load of 20 psf is used in the analyses for the three homes in the evaluation study. This roof live load was based on the slope of the roof and on the largest tributary loaded area for any structural member. Dead load accounts for the self-weight of the structural elements and for all material that permanently exists within the structure. Numerous tables exist in building codes giving material weights that are typically used in residential construction. Such materials are used for roof and wall coverings, frame and/or masonry walls, roof truss material, etc. A uniform dead load of 17 psf was used for this study. 3.1.2 Wind Loads Due to large wind events such as hurricanes, Florida has some of the highest wind load requirements in the United States. Wind generates positive and negative or suction pressure that acts on the surfaces of a structure. As shown in Figure 3-1, the direction of the wind current determines which surface of the structure will be subjected to positive pressure or suction pressure. The windward wall of a structure will experience positive wind pressure due to the wind field acting normal to the surface of the wall. The leeward and sidewalls will experience negative pressure or suction. Different sections of the roof will experience either positive or suction pressure depending on the direction of wind, the plan geometry of the house, and slope of the roof. PAGE 26 14 Figure 3-1. Effects of wind acting on the surface of a residential structure. Ultimately, the wind pressures applied to a structure are based on the location, surrounding environment, and the enclosure classification of that structure. The basic wind speed, used to determine the wind pressure, varies depending on the region of the U.S. where the structure is located (see Figure 3-2). All three model homes used in the evaluation study are assumed to be located in Brevard County, FL, east of Interstate 95 and west of Highway A1A. As shown in Figure 3-2, the wind speed used for determining the required design wind pressures used in the analyses was 125 mph (3-second gust). The surrounding environment of that structure determines the required exposure category as defined in ASCE 7 (ASCE, 1998). An Exposure C category was used due to the location of the project structures being near the shoreline of a hurricane prone region. The conservative assumption also was made that any surrounding structures would be destroyed during a severe wind event changing the exposure from B to C. PAGE 27 15 Figure 3-2. Wind speeds used to determine the design loads for the southeastern United States (ASCE, 1998). Wind not only causes external pressure to be applied to the structural elements, but may also cause internal pressure within the structure. The magnitude of the internal pressure is based on the building classification being either open, partially enclosed, or enclosed. An open building is considered to be a building having each wall at least 80% open. A building is considered partially enclosed if it meets the conditions described in Section 6.2 of ASCE 7-98. A building that does not comply with the requirements for open or partially enclosed buildings is considered an enclosed building (ASCE, 1998). The project structures, with the exception of the front entry and the back porch, are considered to be enclosed structures and will remain enclosed (for analysis purposes) because the glazing used was either impact resistant or protected with an impact resistant PAGE 28 16 covering meeting the requirements of Section 1606.1.4 of the Florida Building Code (SBCCI, 2001). Chapter 16 of the Florida Building Code (SBCCI, 2001) states that the provisions of ASCE 7-98 shall be used to determine wind forces on every building or structure unless certain exceptions or limitations are met. One exception states that a simplified procedure within the FBC is permitted for buildings less than or equal to 60 ft in height. This procedure can be used to determine the design wind pressures to be applied to the structure through the use of tables unlike the formulas used by ASCE 7-98. For determining the applied wind pressures that were used in the analyses of the evaluation study, the option of using the provisions of ASCE 7-98 was taken even though the use of the simplified procedure would have been permitted. 3.2 Description of a Residential Structure A one-story, three or four-bedroom house with an attached garage is a typical layout for a typical residential dwelling in Florida. The plan of this home can vary from a single rectangular shape to more complex shapes such as an or . The evaluation study project structures were L-Shaped and T-shaped in plan as shown in Figure 3-3. The walls were constructed with either CMU block or reinforced concrete monolithically placed. In either case, the roof diaphragm consisted of pre-engineered wood roof trusses and plywood sheathing. Figure 3-4 shows the general representation of a residential structure. The numbered structural components in the figure will be described in the following section. PAGE 29 17 STRUCTURE 1 and 2STRUCTURE 3 Figure 3-3. Plan view of project structures of evaluation study. 3.2.1 Structural Components and Assemblies Structural components are what make up a structural system. Certain elements work together to perform a specific structural function. For example, the gravity load resisting system of a structure consists of multiple elements that work together to resist gravity load only. The main wind force resisting system (MWFRS) is an assemblage of structural components whose primary function is to provide support and stability to a structure subjected to wind loading (ASCE, 1998). The components that provide gravity and lateral support are typically called the primary structural system. Most components in typical residential construction, such as the exterior load-bearing walls (Figure 3-4, Items 1 and 2), serve both of these functions. If an element is subjected to wind and is not considered part of the MWFRS, it is considered components and cladding (C&C). For typical residential structures, the roof diaphragm (Figure 3-4, Item 3) and the exterior walls form the MWFRS. C&C consist of the exterior walls treated as an independent structural element and not part of the MWFRS, roof shingles, roof sheathing, wall siding, PAGE 30 18 doors, garage doors, and windows. The shingles and roof sheathing are shown as Items 4 and 5 of Figure 3-4, respectively. The exterior walls of a house support the gravity loads from the roof trusses and provide lateral resistance to the wind. Exterior walls are subjected to axial loads, out-of-plane bending, and in-plane bending. When the walls are subjected to in-plane bending they are called shear walls (Figure 3-4, Item 2). Walls constructed of CMU or reinforced concrete contain vertical steel reinforcement, which helps resist the effects of the wind loads. The roof diaphragm (Figure 3-4, Item 3) consists of pre-engineered roof trusses (Figure 3-4, Item 6) and plywood or oriented strand board (OSB) roof sheathing (Figure 3-4, Item 5). The roof diaphragm acts as a deep beam that transfers the lateral wind loads to the shear walls. The shear wall acts as a cantilever that transfers the roof diaphragm reaction to the foundation. If the structure is constructed of CMU, a bond beam (Figure 3-4, Item 7) is used to tie all of the exterior walls together and provides anchorage support for the roof diaphragm. A single or multi-course bond beam could be used depending on the magnitude of the applied loads. When the wind pressure is acting normal to the walls, the bond beam acts as the compression and tension chord of the roof diaphragm and aids in transferring the lateral load to the shear walls. When the roof is experiencing uplift forces due to wind, it is transferring these forces from the roof trusses into the vertical reinforcement in the walls. Above all door and window openings in a CMU wall are precast lintels (Figure 3-4, Item 8) that provide support for the section of wall that spans PAGE 31 19 above the opening. Figure 3-5 shows an elevation view wall detail of a double course bond beam and precast lintel. The structural elements described above are an integral part of any basic house whether rectangular in plan or more complex. Other structural elements not listed above can also exist in a residential structure, such as an interior load bearing wall or a floor diaphragm of a two-story house. FOUNDATION 6) ROOF TRUSSES 5) PLYWOOD SHEATHING4) ROOF SHINGLES 3) ROOF DIAPHRAGM WIND LOAD DIRECTION2) Exterior WALLS (Shear Walls Due to wind direction: In-Plane Bending) 1) EXTERIOR WALL (Out-of-Plane Bending) 1) EXTERIOR WALL (Out-of-Plane Bending) 2) Exterior WALLS (Shear Walls Due to wind direction: In-Plane Bending) 8) Pre-cast Lintel 7) Bond Beam Figure 3-4. General representation of a residential structure. PAGE 32 20 Figure 3-5. Elevation view of a CMU wall with a bond beam and precast lintel (SBCCI, 1999). 3.2.2 Connections Connections are a vital element that provide a continuous load path and maintain the overall integrity of the structural system. The most vulnerable connection in residential structures are the nails anchoring the plywood sheathing and the truss tie-downs attaching the pre-engineered trusses to the top of the load bearing walls. The suction caused by the wind moving over a roof causes uplift forces that try to peel away the sheathing if it is not adequately attached. The roof sheathing not only helps the roof act as a diaphragm, but also keeps the structure enclosed. The loss of the building enclosure will cause a change in internal pressure that may lead to further structural damage or overall failure. The truss-to-bearing wall connections or truss tie-downs will experience some of the highest reactions due to wind uplift forces. The loss of one or more truss tie-downs could eventually lead to the failure of the entire roof system. In PAGE 33 21 CMU or concrete construction, the truss straps or tie-downs are embedded into the bond beam or the reinforced concrete wall as shown in Figure 3-6. Figure 3-6. Various roof truss connections to CMU wall. PAGE 34 CHAPTER 4 EVALUATION STUDY OF MERCEDES HOMES SINGLE-FAMILY RESIDENTIAL STRUCTURES 4.1 Evaluation Procedure The three homes selected for this study are similar in layout but differ in overall structural strength. ASCE 7 was used to perform a structural analysis of the homes. Basic strength of materials and engineering mechanics were applied to accomplish this along with guidance from the governing building and design codes such as the Florida Building Code (SBCCI, 2001), American Concrete Instituteâ€™s (ACI) Building Code Requirements for Structural Concrete ACI 318-99 (ACI, 1999), Masonry Society Joint Committeeâ€™s (MSJC) Building Code Requirements for Masonry Structures ACI 530/ASCE 5/TMS 402 (MSJC, 1999), the National Design Specification (NDS) for Wood Construction (AF&PA, 1997), and the American Society of Civil Engineerâ€™s (ASCE) Minimum Design Loads for Buildings and Other Structures ASCE 7-98 (ASCE, 1998). All analyses and design checks conformed to the Allowable Stress Design (ASD) methods within the building code requirements. The only design method available for timber and masonry at the project start-date was ASD. The LRFD approaches were not yet available. The ASD load combinations used in the analyses were that of ASCE 7-98 and are listed in Table 4-1. The load reduction allowed per Section 2.4.3 of ASCE 7-98 was not used in the analyses. When permitted, a one-third allowable stress increase was used. 22 PAGE 35 23 Table 4-1. ASCE 7-98 Section 2.4 ASD basic load combinations. 1D2D + L r 3D + W + L r 40.6D + W A Confidence Factor (C.F.) was calculated for each component based on the structural analysis that was performed. A C.F. is defined as the allowable stress/load divided by the calculated stress/applied load. A C.F. 1.0 meant that the structural resistance of a component exceeded the design loads and a C.F. < 1.0 meant the component might not have the strength required to resist the applied loads, according to the governing code or specification. Components with a C.F. < 1.0 are considered â€œweak linksâ€ or critical components and structural design changes or modifications to the existing structure were then recommended. The complete detailed analyses and design checks for the three homes evaluated as part of this study can be found in Single-Family Residential Structure Evaluation: Phase II of the NQDP (Green & Russell, 2003). 4.2 Structure No. 1 â€“ Baseline Home CMU Home This structure was designed in the mid 1990â€™s and met or exceeded the requirements of the Standard Building Code (SBCCI, 1997) for a basic wind speed of 110 mph (fastest mile). The home is no longer constructed but still exists in many residential communities throughout the state. This home had the weakest overall structural strength of the three houses, its design was based on the less stringent requirements of the 1997 Standard Building Code (SBCCI, 1997), and it was considered the baseline home for the evaluation study. The exterior walls of the house consisted of concrete masonry unit (CMU) construction. The height of the walls were 8-0 and were comprised of 8 block with vertical No. 5 Grade 40 steel reinforcing bars with a maximum horizontal spacing of 10-8. This very large reinforcement spacing was the PAGE 36 24 main reason for the baseline homeâ€™s low overall structural strength. The structure had a covered front-entry and back porch that was made up of pre-engineered trusses, timber headers, and CMU columns (see Figure 4-1). The structure had a flexible roof diaphragm that was made up of pre-engineered wood trusses and plywood sheathing. As shown in Figure 4-1, a load-bearing wood stud wall was used inside the structure to support multiple roof trusses that were spaced at 2-0 on-center and spanned from the interior wall to the CMU wall of the back elevation. BACK TRUSSED PORCHFRONT ENTRY INTERIOR LOAD BEARING WALL RIGHT ELEVATIONLEFT ELEVATIONBACK ELEVATIONFRONT ELEVATION 63'-6" 19'-4" 30'-8" 19'-6" 44'-0" 18'-8" 19'-0" 12'-4" EXTERIOR CMU WALLS 9'-8" GARAGE SIDEWALLGARAGE GOAL POST JACK TRUSSESTRANSFER GIRDER Figure 4-1. Plan view of structure No. 1-baseline home and structure No. 2. PAGE 37 25 4.2.1 Structural Analysis Both the uplift, due to wind, and the downward truss support reactions were taken from the truss package supplied by Space Coast Truss, Inc. (SCT, 2002a). This truss package provided maximum enveloped reactions based on an Exposure C category and a wind speed of 125 mph (3-second gust) as appropriate for Brevard Co., FL. For the lighter jack trusses that had small tributary loaded areas, the support reactions ranged from 291 lbs to 532 lbs of uplift and 145 lbs to 366 lbs of gravity load. The much larger transfer girders, which supported the jack trusses, had support reactions that ranged from 3409 lbs to 3811 lbs of uplift and 3479 lbs to 3694 lbs of gravity load. For all other components that were subjected to wind pressure, ASCE 7 (ASCE, 1998) was used to determine the required design loads. The diaphragm and the CMU shear walls of the MWFRS were subjected to the in-plane lateral forces shown in Figure 4-2. The exterior walls acting as part of the MWFRS were subjected to a maximum uplift pressure of 36.1 psf and wind pressure acting normal to the surface of 19.1 psf. A uniform pressure of 35.5 psf acting normal to the surface of the CMU walls was used when considering the walls to be C&C. A uniform uplift pressure of 112 psf was used as the design wind pressure applied to the plywood sheathing. The full detailed wind pressure calculations can be found in Single-Family Residential Structure Evaluation: Phase II of the NQDP (Green & Russell, 2003). PAGE 38 26 5077 lbs2044 lbs705 lbs2108 lbs1052 lbs267 lbs660 lbs280 lbs39 lbs1642 lbs Figure 4-2. Maximum in-plane lateral forces due to the design wind pressure applied to the exterior CMU walls. The exterior CMU were assumed to span vertically and mortar was applied on the face shells only. Initially, the exterior CMU walls were treated as reinforced masonry for out-of-plane bending. The MSJC states that axial and flexural tension must be resisted entirely by steel reinforcement for reinforced masonry (MSJC, 1999). Using the maximum 10-8 spacing of steel reinforcement, the tributary loaded area acting on a wall section generated axial and bending forces that exceeded the load-moment interaction strength as shown in Figure 4-3A. For unreinforced masonry, the MSJC code allows an allowable flexural tension stress for ungrouted hollow CMU of 25 psi. Considering this, the allowable bending strength of the exterior walls could be increased. However, for any given 12 wall section the applied load combination of D + W + L r still fell outside of the load-moment interaction envelope as shown in Figure 4-3B. PAGE 39 27 Therefore, a typical 12 wall section was determined to be inadequate and unable to resist the out-of-plane bending caused by the applied loading. This was due to the high flexure and the low axial load the wall section experienced. Therefore, it could not achieve its full load-moment interaction capacity. Figure 4-3. Load-moment (P-M) interaction diagrams for exterior CMU walls. A) P-M diagram considering walls to be reinforced masonry. B) P-M diagram considering the walls to be unreinforced masonry. PAGE 40 28 As shown in Figure 4-4, a single course 8 bond beam with a No. 5 steel reinforcing bar placed along the top of the section with 2 of clear cover was used in the baseline home. It was assumed that the mortar joint between the bond beam and the CMU wall would separate, therefore, the bond beam was treated as a multiple span continuous beam with the vertical steel reinforcing acting as the supports. The bond beam was modeled using a commercially available software program. The applied loads were taken from the uplift roof truss reactions provided by Space Coast Truss, Inc. (SCT, 2002a). The bond beam in each wall elevation was considered separately. 2" 7.625" #5 bar 7.625" Figure 4-4. Cross section view of the single course bond beam. Capacity of the bond beam to resist positive and negative bending moments and shear forces were determined along with the anchorage forces of the vertical steel reinforcement. From the analysis results, the maximum positive and maximum negative bending moments acting on the beam were 3325 lb-ft and 2597 lb-ft, respectively. The maximum shear force acting on the bond beam was 3956 lbs. The stresses due to the positive bending moment acting on the steel and masonry were 91,910 psi and 4249 psi, respectively. Due to the negative bending moment, the stress in the masonry was 700 psi and the stress in the steel was 22,734 psi. The resulting stress due to the maximum applied shear force was 91 psi. These stresses clearly exceed the flexural stress of 500 PAGE 41 29 psi for the masonry and 20,000 psi for the steel as allowed by the MSJC along with allowable shear stress of 39 psi. The exterior wall sections between all openings in the right and left elevations were considered to be shear walls. These walls were responsible for resisting all lateral load in the front-to-back or back-to-front direction. The wall sections above and below all openings were not considered to add any resistance to the applied lateral load. Due to many large openings in the front and back elevations, the wall sections between and above these openings were considered as part of the lateral load resisting system in the left-to-right or right-to-left direction. The sections between the openings were assumed to behave as slender columns or piers connected by the bond beam and precast lintels. Figure 4-5 shows the computer model of the back elevation used for the analysis. The composite interaction of the bond beam and the lintel was referred to as a coupling beam. Figure 4-5. Structural analysis result showing deflected shape of the back wall elevation of the structure subjected to in-plane lateral and uplift loading. As shown in Table 4-2, it was determined that the shear walls in the left and right elevations were more than sufficient to resist the lateral loads. Shear Wall 4 and the garage sidewall experienced flexural tension and the vertical steel existing in the wall was more than adequate to carry the tensile stresses. Figure 4-6 shows the shear wall (SW), pier (P), and coupling beam (CB) designations used throughout the analysis. Table 4-3 shows the calculated shear stresses in the piers and the applied bending moments PAGE 42 30 within the coupling beams. Multiple piers experienced large bending moments and all results can be found in the complete report (Green & Russell, 2003). SW1SW2SW1SW2SW3SW4P2CB1P1 P1CB1P2P4CB2P3P1P2P6CB5P4P5CB4CB3CB2CB1P3FRONT ELEVATIONFRONT ENTRYGARAGE SIDEWALLGARAGE GOAL POSTLEFT ELEVATIONRIGHT ELEVATIONBACK ELEVATIONSW: shear wallCB: coupling beamP: pier Figure 4-6. Shear wall designations used in the structural analysis. Table 4-2. Shear wall stresses in the left and right elevations. ElevationShear Wall DesignationCalculated Shear Stress Due to Lateral Load (psi)Allowable Shear Stress (psi)SW12.0240.2SW22.7340.0Garage Sidewall6.6247.4SW10.2441.6SW20.7639.0SW31.1339.0SW41.5047.4LEFTRIGHT PAGE 43 31 Table 4-3. Pier analysis results of the front and back elevations. ElevationPier DesignationCalculated Shear Stress Due to Lateral Load (psi)Allowable Shear Stress (psi)P114.3035.0P24.9035.0P316.5035.0P46.2035.0P132.4035.0P232.4035.0P17.6043.0P21.4035.0P31.2035.0P40.0035.0P50.5035.0P63.4035.0ElevationCoupling Beam DesignationMaximum Bending Moment Caused by Lateral Load (lb-ft)Allowable Bending Moment (lb-ft)CB118506185CB213686185FRONT (Garage Goal Post)CB137636185CB132416185CB27366185CB312406185CB43146185CB53236185BACKFRONT (Garage Goal Post)FRONTBACKFRONT The precast lintels above all openings were checked for positive bending caused by the downward reaction of the roof trusses bearing directly above them. The effects of the wind uplift truss reactions acting on the lintels was considered in the pier analyses. The bond beam, which is the course above the lintel, was considered to act compositely with the lintels (see Figure 4-7) and added to its overall bending resistance. The allowable bending resistances of the lintels spanning 4-6, 6-4, and 16-0 were 9531 lb-ft, 10,542 PAGE 44 32 lb-ft, and 29,250 lb-ft, and more than exceeded the applied loads of 3653 lb-ft, 5117 lb-ft, and 6902 lb-ft, respectively. The calculated maximum shear stress of 32 psi did not exceed the allowable stress of 39 psi. #5 bar 16" 7.625" 2" A A #5 bar steel or prestressing strand varies with spanSection A-A Figure 4-7. Cross-section view of the composite beam: precast lintel and bond beam. An assemblage of pre-engineered roof trusses and timber headers supported by CMU columns covers the back porch and the front entry as shown in Figure 4-8. The back trussed-porch consisted of a double 2x12 header that supported the roof trusses. CMU columns were used to support the headers. Using the roof truss reactions, it was determined that the bending stress in the header was 594 psi due to wind uplift and 754 psi due to gravity loads. The bending stresses allowed by the NDS (AF&PA, 1997) for the headers subjected to bending due to uplift and gravity loads were 1560 psi and 1219 psi, respectively. The maximum shear stress in the header was 69 psi, which did not exceed the allowable shear stress of 113 psi given by the NDS. The CMU columns were subjected to a maximum axial compressive force of 3640 lbs and an axial tensile force of 1839 lbs. The allowable axial compressive and tensile forces were 42,666 lbs and 6200 PAGE 45 33 lbs, respectively. It was concluded that the capacities of the timber headers and the CMU columns were more than sufficient to resist the applied loads. Using the roof truss reactions provided by Space Coast Truss (SCT, 2002a), the bending stresses generated in the double 2x8 timber headers of the front entry were 240 psi due to wind uplift and 330 psi due to the gravity loads. The allowable bending stresses for the headers due to uplift and gravity loads were 1920 psi and 1500 psi, respectively. The maximum shear stress in the header was 25 psi, which did not exceed the allowable shear stress of 113 psi given by the NDS. The CMU columns were subjected to a maximum axial compressive force of 3205 lbs and an axial tensile force of 622 lbs. The allowable axial compressive and tensile forces of the CMU columns were 88,625 lbs and 2480 lbs, respectively. It was concluded that the capacities of the timber headers and the CMU columns of the front entry were more than sufficient to resist the applied loads. (2) 2x8 Headerw/ 1/2" of solid spacing CMU Columns (2) 2x12 Headerw/ 1/2" of solid spacingCMU Columns Gable End Truss AB Figure 4-8. Elevation view of back trussed-porch and front entry. A) Back Trussed Porch. B) Front Entry. As shown in Figure 4-1, an 8-0 high interior load-bearing wall was used within Structure No. 1 to support multiple roof trusses. This wall was constructed from timber PAGE 46 34 2x4 vertical studs, a double top plate, and a single base plate. The timber wall was anchored to the foundation and the CMU exterior wall using diameter j-bolt connections. Due to the lack of accurate detailing of the interior wall, assumptions were made about the locations of the vertical studs. The studs were assumed to be in a location that provided the maximum or worst-case loading of the top plate. Based on these locations, it was determined from multiple design checks that the top plate was sufficient to resist all applied bending moments but was not adequate to resist the applied shear forces. The capacity of each vertical stud was sufficient to resist the applied tensile force but insufficient to resist the applied compression force. All calculated and allowable stresses of the elements that make up the interior load-bearing wall are provided in Table 4-4. Table 4-4. Results of multiple design checks of the interior load-bearing wall. Calculated Bending Stress (psi)Allowable Bending Stress (psi)Uplift Bending14792640Gravity Bending12812063Uplift Shear208144Gravity Shear180113Calculated Stress (psi)Allowable Stress (psi)Uplift6801063Gravity663644Calculated Load on Connection (lbs)Allowable Load on Connection (lbs)Uplift723996DOUBLE TOP PLATEVERTICAL STUDSJ-BOLT CONNECTIONS PAGE 47 35 Design checks were conducted on the anchorage of the garage door, doors/sliding glass door, and the windows. The garage door assembly consisted of 2x6x8 timber members standing vertical at the ends of the garage opening and a 2x6x16 member running along the top of the opening as shown in Figure 4-9. It was assumed that only the J-bolts with a 2 washer would carry the applied wind pressure loading of 35.5 psf. The allowable compressive strength of the wood was determined to be the governing element while the strength and the withdrawal capacity of the J-bolts from the concrete were not considered. The applied load on each J-bolt was 694 lbs. Based on the compressive strength of the wood, the load allowed by the NDS on each bolt was 996 lbs. 232.0" 88.0" Prestressed Concrete Lintel 1 2" Dia. J-Bolt with 2" Washer 192.0" Pressure Treated 2x6x16'Attached with TapCons 32.0" Pressure Treated 2x6x8' Each End 32.2" 16.2" 16.0" Bond Beam 32.0" 104.0" 16.2" 32.2" 16.0" Figure 4-9. Elevation view of the garage door and anchorage. As shown in Figure 4-10, all window and door anchorage consists of 1x4 timber bucks connected to the CMU with 2 long 3 / 16 TapCon anchors. It was determined that the maximum applied shear force on each anchor was 242 lbs, which is less than the allowable shear strength of 255 lbs. PAGE 48 36 PT 1x4 Door BuckStrips Anchor toBlock with 3/16" TapCon 2" length@ 24" o.c. Bond BeamP.C. LintelCMU Wall 72.0" 73.5" P.C. LintelBond BeamCMU Pier PT 1x4 Door BuckStrips Anchor toBlock with 3 16" TapCon 2" length@ 24" o.c. 80.0" 72.0" AB Figure 4-10. Details of door and window anchorage. A) Sliding glass door anchorage. B) Window anchorage. The 15 / 32 plywood sheathing of the roof diaphragm had an allowable bending stress of 2640 psi and an allowable shear stress of 77 psi. Based on these stresses, the maximum uniform pressure that can act on the sheathing is 117 psf. The maximum applied design pressure acting on the sheathing was 106 psf. Therefore, the applied design loads did not exceed the capacity of the sheathing. Based on the nail size and schedule shown in Figure 4-11, the maximum tensile or pullout load acting on each nail was 76 lbs and the withdrawal capacity of each nail was calculated to be 98.4 lbs. Therefore, it was concluded that the nail size and the number of nails (i.e. nail pattern) were adequate to anchor the 15 / 32 plywood sheathing. PAGE 49 37 15/32" plywood C-D or7/16" APA rated osb8d gun nails at 4" o.c. on edges and 8" o.c. in fieldwithin 48" of gable end 8d gun nails at 6" o.c. on joints and edges and 12" o.c. in field Figure 4-11. Nail size and schedule anchoring the roof sheathing. An evaluation of the truss-to-bond beam connections along with the connections that assemble the back trussed porch and the front entry was conducted. The maximum enveloped truss reactions provided by Space Coast Truss (SCT, 2002a) were compared to the anchor/connector schedule located within the structural details of the construction plans. Multiple truss reactions and connectors were not adequate to resist the applied loading. For a full listing of the capacities and applied loadings of the anchor/connectors, refer to Appendix A. 4.2.2 Summary of Results As discussed in the Structural Analysis Section 4.2.1, and shown in Table 4-5, the areas of concern for the baseline home are the exterior CMU walls, the bond beam, the interior load bearing wall, and the anchor/connections. These results were not totally unexpected mainly because the applied loading requirements used in all analyses conformed to the FBC (SBCCI, 2001) and the baseline home was designed conforming to PAGE 50 38 the 1997 Standard Building Code (SBCCI, 1997). The complete evaluation summary for the Baseline Home (Structure No.1) can be found in Appendix A. Table 4-5. Confidence factors of baseline home. 1. Exterior CMU Walls (Axial & Out-of-Plane Bending): General wall sections. C.F. 1.0 Areas of concern 2. Exterior CMU Walls (Axial & In-Plane Bending): C.F. 7.2 No design improvements required 3. Exterior CMU Walls â€“ Pier Analysis (Axial & In-Plane Bending): C.F. 1.2 Flexure No immediate design changes required C.F. 1.1 Shear No immediate design changes required C.F. 1.01 P-M Interaction Possible areas of concern 4. Bond Beam and Anchorage: C.F. 1.0 Areas of concern 5. Precast and Prestressed Lintels: C.F. 1.2 No immediate design changes required 6. a) Back Trussed Porch/ b) Front Entry/ c) Interior Load Bearing Wall: a) C.F. 1.6 No immediate design changes required b) C.F. 4.5 No immediate design changes required c) C.F. 1.0 Areas of concern 7. Door and Window Anchorage/Roof Sheathing: C.F. 1.0 Possible areas of concern 8. Connections (truss-to-bond beam, back trussed porch, front entry): C.F. 1.0 Areas of concern 4.3 Structure No. 2 â€“ CMU Home This structure was designed in 2002 and met or exceeded the requirements of the Florida Building Code (SBCCI, 2001) for a basic wind speed of 130 mph (3-second gust). Since the adoption of the FBC, this house design has since replaced that of the Baseline Home (Structure No. 1). The layout and design of Structure No. 2 is identical to the Baseline Home except that the vertical steel reinforcement within the CMU walls has been reduced and the type, quantity and/or location of the anchors/connectors has been revised. The height of the walls were 8-0 and were comprised of 8 block with vertical PAGE 51 39 No. 5 Grade 40 steel reinforcing bars, as were the walls of the Baseline Home. The maximum horizontal spacing of the vertical reinforcement was now 7-8. 4.3.1 Structural Analysis For evaluation purposes, only the CMU exterior walls and bond beam were re-analyzed. The new truss anchor/connector capacities were compared to the applied maximum enveloped truss reactions provided by Space Coast Truss (SCT, 2002a), which were the same as those of the Baseline Home. All design wind pressures determined and used in the analyses of the Baseline Home also applied for Structure No. 2. By observation, the critical exterior CMU wall sections were in the back and left elevations as shown in Figure 4-12. The back elevation contained many openings and due to these openings, an 8 wide section of wall lies between the back sliding glass door and the back windows. This section of wall acted as a beam-column and carried a large axial force and bending moment. The left elevation had the largest spacing of vertical reinforcement. This wall section carried a small axial load and a large bending moment. The tributary areas shown in Figure 4-12 were based on center-to-center spacing of reinforcement and the span of the pre-engineered trusses that acted on a particular section of wall. PAGE 52 40 Tributary width = 7'-8" LEFT ELEVATION Tributary length = 5' Tributary length = 23' Critical Wall Section : 8" wide piers Tributary area applies for only 8" wide piers. Tributary area applies for all wall sections in left elevation. Critical Wall Section largest rebar spacing. Tributary width = 6' 1" BACK ELEVATION Figure 4-12. Critical exterior CMU wall sections of structure No. 2. The 8 beam-column in the back elevation was more than sufficient to resist axial load. However, from the load-moment interaction diagram shown in Figure 4-13 it is clear that when the axial load is combined with a large bending moment, the capacity of the wall section is not adequate. The load combinations of D + W + L r and 0.6D + W fell outside of the load-moment interaction envelope. For the critical wall section in the left elevation, all load combinations fell within the P-M interaction envelope as shown in Figure 4-14. Therefore, it was concluded that all general wall sections were adequate to resist any and all applied loading. PAGE 53 41 05001000150020001104210431044104 P-M Diagram Moment (lbf-ft)Load (lbf)PdPeulerPloadsMdMeulerMloads Figure 4-13. Load-moment interaction diagram for 8 wall section in the back elevation. 010002000300040005000600070008000900021044104610481041105 P-M Diagram Moment (lbf-ft)Load (lbf)PdPeulerPloadsMdMeulerMloads Figure 4-14. Load-moment interaction diagram for critical section in the left elevation. The bond beam in Structure No. 2 was identical to that of the bond beam used in the Baseline Home (see Figure 4-4). However, due to the decrease in the spacing of the PAGE 54 42 vertical steel reinforcement, additional support locations were now provided. A revised bond beam analysis was carried out to determine whether it was adequate. For the bond beam analysis, the same assumptions and procedures used in the Baseline Home were applied. The maximum positive and maximum negative bending moments acting on the beam were 2797 lb-ft and 2084 lb-ft, respectively. The maximum shear force acting on the bond beam was 3956 lbs. The stresses due to positive bending moment acting on the steel and masonry were 76625 psi and 3574 psi, respectively. Due to the negative bending moment, the stress in the masonry was 562 psi and the stress in the steel was 18,243 psi. The resulting stress due to the maximum applied shear force was 91 psi. These stresses still clearly exceeded the allowable flexural stress of 500 psi for the masonry and 20,000 psi for the steel as given by the MSJC along with an allowable shear stress of 39 psi. Since Structure No. 2 was designed for a basic wind speed of 130 mph (3-second gust), the capacities of the truss-to-bond beam anchorage along with the connections that assemble the back trussed porch and the front entry had been increased. The maximum enveloped truss reactions provided by Space Coast Truss (SCT, 2002a), also used for the Baseline Home, were compared to the anchor/connector schedule located within the structural details of the construction plans. The increase in the anchor/connector strength provided enough capacity to resist all applied loading. For the full listing of the capacities and applied loadings of the anchor/connectors, refer to Appendix B. 4.3.2 Summary of Results The components with a C.F. < 1.0 for Structure No. 2 are the exterior CMU walls, the bond beam, and the interior load-bearing wall as shown in Table 4-6. Specifically, the 8 wall section in the back elevation and the bond beamâ€™s lack of resistance for PAGE 55 43 positive bending and shear force are the areas of concern. The complete evaluation summary for Structure No. 2 can be found in Appendix B. Table 4-6. Confidence factors for structure No. 2. 1. Exterior CMU Walls (Axial & Out-of-Plane Bending)*: Wall sections adjacent to openings. C.F. 1.0 Areas of concern 2. Exterior CMU Walls (Axial & In-Plane Bending): C.F. 7.2 No design improvements required 3. Exterior CMU Walls â€“ Pier Analysis (Axial & In-Plane Bending): C.F. 1.2 Flexure No immediate design changes requiredC.F. 1.1 Shear No immediate design changes requiredC.F. 1.01 P-M Interaction Possible Areas of concern 4. Bond Beam and Anchorage: C.F. 1.0 Areas of concern 5. Precast and Prestressed Lintels: C.F. 1.2 No immediate design changes required 6. a) Back Trussed Porch/ b) Front Entry/ c) Interior Load Bearing Wall: a) C.F. 1.6 No immediate design changes required b) C.F. 4.5 No immediate design changes required c) C.F. 1.0 Areas of concern 7. Door and Window Anchorage/Roof Sheathing: C.F. 1.0 Possible areas of concern 8. Connections (truss-to-bond beam, back trussed porch, front entry): C.F. 1.1 No immediate design changes required *Note: Items in bold indicate that new analyses were conducted due to changes in design between Structure 2 and the Baseline Home. 4.4 Structure No. 3 â€“ Concrete Home This structure was designed in 2000 and met or exceeded the requirements of the Standard Building Code (SBCCI, 1997) for a basic wind speed of 110 mph (fastest mile). This structure was considered to be the more structurally sound home of the three considered in this evaluations study. The exterior walls of the house were constructed from monolithically placed reinforced concrete. The height of the walls were 9-0 and were 6 thick. The steel reinforcement within the walls consisted of a vertical single No. PAGE 56 44 5 bar at a spacing of 4-0 on-center along with 6x6 8-gage wire mesh that ran down the middle of the walls. The structure had a back porch that was made up of pre-engineered trusses, timber headers, and timber columns (see Figure 4-15). The structure had a flexible roof diaphragm that was made up of pre-engineered wood trusses and plywood sheathing. As shown in Figure 4-15, load-bearing wood stud walls were used within the interior of the structure to support multiple roof trusses that were spaced at 2-0 on-center and spanned from the interior walls to the concrete wall of the back and left elevations. The alternative design method for reinforced concrete found in Appendix A of ACI 318 (ACI, 1999) was used for the analysis of Structure No. 3. LEFT ELEVATIONGARAGE SIDEWALLGARAGE GOAL POSTFRONT ELEVATIONRIGHT ELEVATIONEXTERIOR CONCRETE WALLSBACK TRUSSED PORCHBACK ELEVATIONINTERIOR LOAD BEARING WALLS 19'-4" 19'-0" 11'-8" 61'-4" 30'-8" 19'-4" TRANSFER GIRDER JACK TRUSSES 8'-0" 44'-0" 9'-4" BACK BEDROOMSIDE WALL Figure 4-15. Plan view of structure No. 3. PAGE 57 45 4.4.1 Structural Analysis The minimum design wind loads were determined for Structure No. 3. Since the geometry and roof slope were different than that of Structures No. 1 and No. 2. Also, an additional truss package was required from Space Coast Truss, Inc. (SCT, 2002b). This truss package provided maximum enveloped reactions based on an Exposure C category and a wind speed of 125 mph (3-second gust) as appropriate for Brevard Co., FL. For the lighter jack trusses that had small tributary loaded areas, the support reactions ranged from 283 lbs to 504 lbs of uplift and 144 lbs to 357 lbs of gravity load. The much larger transfer girders, which supported the jack trusses, had support reactions that ranged from 3574 lbs to 3948 lbs of uplift and 3373 lbs to 3739 lbs of gravity load. For all other components of Structure No. 3 that were subjected to wind pressure, ASCE 7 (ASCE, 1998) was used to determine the required design loads. The roof diaphragm and the concrete shear walls of the MWFRS were subjected to the in-plane lateral forces shown in Figure 4-16. The exterior walls acting as part of the MWFRS were subjected to a maximum uplift pressure of 22.1 psf and wind pressure acting normal to the surface of 20.7 psf. A uniform pressure of 34.1 psf acting normal to the surface of the concrete walls was used when considering the walls to be C&C. A uniform uplift pressure of 112 psf was used as the design wind pressure applied to the plywood sheathing. The full detailed wind pressure calculations can be found in Single-Family Residential Structure Evaluation: Phase II of the NQDP (Green & Russell, 2003). PAGE 58 46 3638 lbs 805 lbs 1815 lbs 1089 lbs 948 lbs 389 lbs 1306 lbs 191 lbs 23 lbs 698 lbs 656 lbs447 lbs2429 lbs 1341 lbs Figure 4-16. Maximum in-plane lateral forces due to the design wind pressure applied to the exterior concrete walls. Of the three project structures, the exterior walls of Structure No. 3 were the strongest. By observation, the critical exterior concrete wall sections were in the back and left side elevations as shown in Figure 4-17. The sliding glass door in the back elevation was the largest opening with the sections of wall immediately adjacent to the sliding glass door that carried the load transferred from the door. This section of wall acted as a beam-column and carried a large axial force and a large bending moment. The largest spacing of vertical steel reinforcement in the wall was 4-0 on-center. The side elevations were critical due to the wall sections being subjected to large bending moments and small axial loads. These wall sections were evaluated on a per foot of wall basis. The tributary areas shown in Figure 4-17 were based on center-to-center spacing PAGE 59 47 of reinforcement and the span of the pre-engineered trusses that acted on a particular section of wall. BACK ELEVATION Tributary length = 22' LEFT ELEVATION Tributary width = 1' Tributary length = 5' Tributary width = 6.25' Figure 4-17. Critical exterior concrete wall sections of structure No. 3. As seen in the P-M diagram (Figure 4-18), the 12 wall section adjacent to the sliding glass door was not adequate to resist the applied loading. The load combination of D + W + L r fell outside of the load-moment interaction envelope. For the critical wall sections in the side elevations, all load combinations fell within the P-M interaction envelope as shown in Figure 4-19. Therefore, it was concluded that all typical wall sections were adequate to resist the applied loading. PAGE 60 48 050010001500200025003000350011042104 P-M Diagram Moment (lbf-ft)Load (lbf)PdPloadsMdMloads Figure 4-18. Load-moment interaction diagram for 12 wall section adjacent to sliding glass door in the back elevation. 0500100015002000250030003500500011041.510421042.5104 P-M Diagram Moment (lbf-ft)Load (lbf)PdPloadsMdMloads Figure 4-19. Load-moment interaction diagram for typical wall section (per foot of wall). The capacity of wall sections above all openings were also determined. The concrete coupling beams consisted of a single No. 5 reinforcing bar at the top and bottom of the section as shown in Figure 4-20. Three critical coupling beams were investigated: PAGE 61 49 the coupling beams over both openings in the back elevation and the garage door. Due to the symmetry of the beam, the sectionâ€™s resistance to bending was equal when considering positive and negative bending. The capacity of the coupling beams to resist bending moment and shear forces was determined. From the analysis results, the maximum bending moment on the coupling beam was 4558 lb-ft. The maximum shear force acting on the coupling beam was 4425lbs. The resulting stress due to the maximum applied shear force was 46 psi. The maximum allowable bending moment was 6503 lb-ft. The shear stress allowed by ACI 318-99 was 55 psi. 6.0" 16.0" 2.0" 2.0" No. 5 Reinforcing Bars Figure 4-20. Cross-section view of the coupling beam. The exterior wall sections between all openings in the right, left, and back elevations were considered to be shear walls. These walls were responsible for resisting all in-plane lateral loads as previously shown in Figure 4-16. The wall sections above and below all openings were not considered to add any resistance to the applied lateral load. Due to many large openings in the front elevation, the wall sections between and above these openings were considered as part of the lateral load resisting system. The sections between the openings were assumed to behave as slender columns or piers PAGE 62 50 connected by the coupling. Figure 4-21 shows the shear wall (SW), pier (P), and coupling beam (CB) designations used throughout the analysis Structure No. 3. As shown in Table 4-7, it was determined that the shear walls in the left, right, and back elevations were more than sufficient to resist the lateral loads. Several shear walls experienced flexural tension and the vertical steel existing in the wall was more than adequate to carry the tensile stresses. Table 4-8 shows the calculated shear stresses in the piers and the applied bending moments within the coupling beams of the front elevation. Multiple piers experienced large bending moments and all results can be found in the complete report (Green & Russell, 2003). SW: shear wallCB: coupling beamP: pierLEFT ELEVATIONFRONT ELEVATIONGARAGE GOAL POSTGARAGE SIDEWALLRIGHT ELEVATIONBACK ELEVATION SW1SW2SW4SW3SW2SW1CB1P1P2P1CB1P2P3CB2P4BEDROOM SIDE WALLSW1SW2SW3SW4 Figure 4-21. Shear designations of structure No. 3 used in the structural analysis. PAGE 63 51 Table 4-7. Shear wall stresses in the left, right, and back elevations. ElevationShear Wall DesignationCalculated Shear Stress Due to Lateral Load (psi)Allowable Shear Stress (psi)SW10.8655SW20.8255Garage Sidewall2.5755Bedroom Sidewall2.1955SW10.0855SW20.2855SW30.3955SW40.5255SW11.3855SW23.7555SW31.7555SW40.5055LEFTBACKRIGHT Table 4-8. Pier analysis results of the front elevation. ElevationPier DesignationCalculated Shear Stress Due to Lateral Load and Uplift (psi)Allowable Shear Stress (psi)P15.8055P22.3055P34.9055P40.5055P14.6055P24.6055ElevationCoupling Beam DesignationMaximum Bending Moment Caused by Lateral Load and Uplift (lb-ft)Allowable Bending Moment (lb-ft)CB112786185CB25196185FRONT (Garage Goal Post)CB114596185FRONTFRONT (Garage Goal Post)FRONT The back porch was covered by an assemblage of pre-engineered roof trusses and timber headers supported by a timber post as shown in Figure 4-22. The back trussed-porch consisted of two double 2x12 headers that supported the roof trusses. A 4x4 timber PAGE 64 52 post column was used to support one end of the headers. Using the roof truss reactions, it was determined that the bending stress in Header 1 was 673 psi due to wind uplift and 473 psi due to gravity loads. The bending stress in Header 2 was 1234 psi due to wind uplift and 821 psi due to gravity loads. The bending stresses allowed by the NDS (AF&PA, 1997) for the headers subjected to bending due to uplift and gravity loads were 1560 psi and 1219 psi, respectively. The maximum shear stress acting in the headers was 88 psi, which did not exceed the allowable shear stress of 144 psi given by the NDS. The 4x4 timber column was subjected to a maximum axial compressive stress of 184 psi and an axial tensile stress of 241 psi. The axial compressive and tensile stresses allowed by the NDS (AF&PA, 1997) for the timber column were 582 psi and 1063 psi, respectively. It was concluded that the capacities of the timber headers and the 4x4 timber column were more than sufficient to resist the applied loads. P.T. 4x4 TypicalAll Posts P.T. 4x4 TypicalAll Posts Typical Concrete Wall Typical Concrete Wall (2) 2x12 Header 1Pre-engineered Trusses Pre-engineered Trusses(2) 2x12 Header 2 A)B) Figure 4-22. Back trussed porch of structure No. 3. A) Side view. B) Elevation view. As shown in Figure 4-15, two 9-0 high interior load-bearing walls were used within Structure No. 3 to support multiple roof trusses. These walls were constructed from timber 2x4 vertical studs, a double top plate, and a single base plate similar to that used in Structures No. 1 and 2. The timber walls were anchored to the foundation and the exterior concrete walls using diameter j-bolt connections. The assumptions made for PAGE 65 53 the design layout of the interior wall in Structures No. 1 and 2 also applied for the analyses for these walls. Multiple design checks concluded that the top plate was sufficient to resist all applied bending moments but was not adequate to resist the applied shear forces. The capacity of the vertical studs were sufficient to resist the applied tensile force but insufficient to resist the applied compression force. All calculated and allowable stresses of the elements that make up the interior load-bearing wall can be seen in Table 4-9. Table 4-9. Results of multiple design checks of the interior load-bearing walls. Calculated Stress (psi)Allowable Stress (psi)Uplift Bending13582640Gravity Bending14542063Uplift Shear213144Gravity Shear228113Calculated Stress (psi)Allowable Stress (psi)Uplift Tension7191063Gravity Compression682515Calculated Load on Connection (lbs)Allowable Load on Connection (lbs)Uplift949996DOUBLE TOP PLATEVERTICAL STUDSJ-BOLT CONNECTIONS Neither the applied design loading nor the design of the roof sheathing changed for Structure No. 3. The design of the anchorage of the garage door, doors/sliding glass door, and the windows did not change and the applied loading only decreased slightly. Therefore, the components of Structure No. 3 were not re-evaluated. PAGE 66 54 Evaluation of the truss-to-bond beam connections along with the connections that assemble the back-trussed porch was conducted. The maximum enveloped truss reactions provided by Space Coast Truss (SCT, 2002b) were compared to the anchor/connector schedule located within the structural details of the construction plans. Multiple truss reactions and connectors were not adequate to resist the applied loading. For the full listing of the capacities and applied loadings of the anchor/connectors, refer to Appendix C. 4.4.2 Summary of Results The components with a C.F. < 1.0 for Structure No. 3 are the exterior concrete walls, the interior load-bearing walls, and the truss-to-wall connections as shown in Table 4-10. The complete evaluation summary is located in Appendix C. Table 4-10. Confidence factors for structure No. 3. 1. Exterior Concrete Walls (Axial & Out-of-Plane Bending)*: Wall sections adjacent to openings. C.F. 1.0 Areas of Concern 2. Exterior Concrete Walls (Axial & In-Plane Bending): C.F. 14.7 No design improvements required 3. Exterior Concrete Walls â€“ Pier Analysis (Axial & In-Plane Bending): C.F. 3.65 Flexure No immediate design changes required C.F. 7.7 Shear No immediate design changes required C.F. 1.47 P-M Interaction Possible area of concern 4. Coupling Beams: C.F. 1.2 No immediate design changes required 5. a) Back Trussed Porch/ b) Interior Load Bearing Wall: a) C.F. 1.26 Immediate design changes required b) C.F. 1.0 Areas of Concern 6. Door and Window Anchorage/Roof Sheathing: C.F. 1.0 Possible area of concern 7. Connections (truss-to-bond beam, back trussed porch): C.F. 1.0 Areas of Concern *Note: Items in bold indicate that new analysis were conducted due to changes in design between Structure 3 and Structures 1 (Baseline) and 2. PAGE 67 CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS 5.1 Conclusions of the Evaluation Study The purpose of this study was to evaluate and compare the overall structural strength of three different single-family residential structures exposed to hurricane-force winds and to identify any critical components that may be present in the structures. The results of the study are to aid in the design of an improved hurricane resistant demonstration home. The extensive analyses and design checks yielded results based on the given layout and design of the structures. Houses 1 and 3 were designed to the 1997 Standard Building Code while house 2 was designed in accordance with the Florida Building Code. The basic wind speed used in the design of the structures also determined the overall structural strength. Structures No. 1 and 3 was designed using a fastest mile wind speed of 110 mph and Structure No. 2 was designed with a 3-second gust wind speed of 130 mph. A 110 mph fastest mile is approximately equal to a 130 3-second gust. The three houses all performed poorly in transferring uplift and lateral load due to wind to the foundation. The critical components for each structure were identified in Chapter 4 and summarized as part of Tables 4-5, 4-6, and 4-10 for the Baseline Home, Structure No. 2 and Structure No. 3, respectively. The structural components that were found to be critical were the following: Truss anchors/connectors 55 PAGE 68 56 o It is determined that design error was the cause for multiple inadequate connections in Structures No. 1 and 3. o The anchors used in Structure No. 2 were sufficient. Exterior concrete and CMU walls o All general walls sections of Structure No. 1 were not in compliance with the governing code. o General wall sections of Structures No. 2 and 3 were sufficient in accordance with the building code; however, the wall sections adjacent to openings were inadequate based on the design assumptions made and the approach taken. Interior wood load bearing walls o Insufficient detailing was provided in the construction plans and â€œworst-caseâ€ loading assumptions were made. o Actual construction of walls on-site could prove to be adequate. Reinforced CMU bond beam o Failure based on large vertical steel spacing of Structure No.1 o Placement of horizontal reinforcement on bond beam is efficient in resisting negative bending moment only. These critical components were identified after a Confidence Factor was determined based on detailed analyses carried out (Green & Russell, 2003). Only components that had C.F. < 1.0 were considered as a possible area of concern that should be evaluated further. The following section gives some recommendations for improving, strengthening, or redesigning the critical components. 5.2 Recommendations for Further Improvements The following recommendations were based on the results obtained from the evaluation study and are only applied to the critical â€œweak linkâ€ component (i.e. C.F. <1.0). PAGE 69 57 5.2.1 General Recommendations Based on the conclusion that designer error was the reason for inadequate truss anchors/connectors, no improvements are recommended. In general, the vertical steel reinforcement spacing of the CMU and concrete walls should be no greater than 6-0. This will provide the strength required to resist out-of-plane bending, however, it is recommended that further investigation be conducted into detailing practice of the wall sections adjacent to openings. It is suggested that accurate detailing be provided within the sealed construction plans in order to determine the true strength of the interior wood load-bearing walls. Based on the assumptions made, improvements are also suggested for the CMU bond beam found in the Baseline Home and Structure No. 2. A double course bond beam would provide a substantial increase in uplift transfer capacity for the masonry walls. 5.2.2 Specific Recommendations Specific to Structures No. 1 and No. 2, a 8x8 concrete column with the appropriate steel reinforcement to resist the applied loading is suggested to replace the 8 CMU pier between openings in the back elevation. The use of reinforced concrete allows for efficient placement of the steel reinforcement as opposed to the limited location of steel in the hollow core of a concrete masonry unit. The suggested section along with the steel reinforcement configuration is shown in Figure 5-1. For the CMU exterior walls, a 16 double course bond beam is recommended. A single #5 steel reinforcement bar should be placed at both the top and bottom of the sections, as shown in Figure 5-2. This would provide a sufficient bending capacity to resist the negative and positive bending moments and shear forces that are induced into the bond beam by wind uplift. Appropriate structural analysis of this suggested bond PAGE 70 58 beam is found in Appendix D. The suggested use of a double course bond beam will lead to an increase in the wall height of the CMU homes. In order to maintain the desired wall height it is suggested that the precast concrete lintel be eliminated and that the applied loads above all openings be resisted exclusively by the bond beam, as shown in Figure 53. Figure 5-1. Suggested reinforced concrete column to replace CMU pier. 8" 8" provide appropriate reinforcement at corners of section 1.5" 1.5" Section A-AAABACK ELEVATION #5 bar 2" 15.625" #5 bar knockout web bond beam unitLintel block unit 2" 7.625" Figure 5-2. Detail of suggested 16 double course bond beam. PAGE 71 59 Double Reinforced Bond Beam 8" CMU Roof Truss and Anchorage Figure 5-3. Suggested continuous bond beam acting as lintel (SBCCI, 1999). 5.3 Future Research It is suggested that further research be conducted based on the suggested recommendations in Section 5.2. The ASD method used for the evaluation study should be compared to a strength approach such as Load and Resistance Factor Design (LRFD) method. The LRFD approach could prove to be beneficial in obtaining an increased capacity of the structural components analyzed. Another suggested future study involves the economics of incorporating the specific recommendations into an improved hurricane resistant house. For instance, a double bond beam will add additional strength to the structure, however it might be uneconomical to build and therefore, a more economical solution needs to be found. Lastly, the conservatism used in the detailed analyses should be reviewed. For example, the option to not use the load reductions allowed by ASCE 7 in the analyses of Chapter 4, were conservative. PAGE 72 60 One of the goals of the evaluation study conducted for Phase II of the NQDP was to aid in the design of an improved hurricane-resistant demonstration home that would be capable of withstanding 140-150 mph hurricane force winds. It is anticipated that this home will be constructed in Brevard County, FL, as this was the location of the project structures. Within this home the critical components identified from the evaluation study will be instrumented as well as those determined to be adequate. The instrumentation will be capable of monitoring the strains, displacements (absolute and relative), and/or rotations of components or between components when subjected to an applied loading (gravity or wind). This data will be used to identify how these loads are actually transferred from the roof of the structure to the foundation and what load paths are being taken. Having this detailed information will enable researchers to clearly understand the behavior of single-family residential structures when subjected to hurricane-force winds and what is required to resist those loads. PAGE 73 APPENDIX A EVALUATION SUMMARY OF STRUCTURE NO. 1 BASELINE HOME A Confidence Factor (C.F.) has been given to each element and is defined as the allowable stress divided by the calculated stress. Any element possessing a C.F. greater than or equal to 1.0 is considered safe and no immediate design improvements are necessary. If a particular element has a C.F. less than 1.0, the calculated stress exceeds the allowable stress and immediate design improvements may be necessary. The C.F. (as defined in this study) is not to be confused with a Factor of Safety (F.S.). A F.S. was already incorporated in the allowable stress of the structural materials and hence included in the calculation of the C.F. The following Sections A1 through A8 summarize the analytical evaluation of the Baseline home (Structure 1) giving the minimum confidence factor for each major element that makes up the Main Wind Force Resisting System (MWFRS) and the Components and Cladding (C&C). 61 PAGE 74 62 A1. Exterior CMU Walls (Axial & Out-of-Plane Bending): Figure A-1 shows the P-M diagram for all exterior CMU walls treated as one foot strips of wall. The critical combination of applied bending moment and axial load is 284lbf-ft/ft and 95lbf/ft, respectively. 05001000150020000500011041.5104 Unreinforced CMU P-M Interaction DiagramMoment (lb-ft)Load (lb)PPcPappliedMMcMapplied Figure A-1. Load-moment interaction diagram for the exterior CMU walls (per foot of wall). Design must satisfy the following relationship. 0.1tabFff 0.1ttFAPFSM 17.13.3330953.338128423 psiinlbfpsiinftlbf Confidence Factor 85.17.11..FC PAGE 75 63 A2. Exterior CMU Walls Shear Walls (Axial & In-Plane Bending): The shear walls of the project structure are more than sufficient to resist the applied lateral forces. RIGHT ELEVATION LEFT ELEVATIONSW 1SW 2SW 3SW 4SW 2SW 1GARAGE SIDEWALL Figure A-2. Shear wall locations in the right and left elevations along with the garage sidewall. LEFT ELEVATION: Shear Wall #1 RIGHT ELEVATION: Shear Wall #1 Allowable Stress: F v = 41.64psi Allowable Stress: F v = 40.2psi Calculated Stress: f v = 0.24psi Calculated Stress: f v = 2.0psi Confidence Factor: C.F. = 51.2 Confidence Factor: C.F. = 20.1 LEFT ELEVATION: Shear Wall #2 RIGHT ELEVATION: Shear Wall #2 Allowable Stress: F v = 38.9psi Allowable Stress: F v = 39.99psi Calculated Stress: f v = 0.76psi Calculated Stress: f v = 2.73psi Confidence Factor: C.F. = 173.5 Confidence Factor: C.F. = 14.6 LEFT ELEVATION: Shear Wall #3 Allowable Stress: F v = 38.9psi Calculated Stress: f v = 1.13psi Confidence Factor: C.F. = 34.4 LEFT ELEVATION: Shear Wall #4 GARAGE SIDEWALL: Allowable Stress: F v = 47.4psi Allowable Stress: F v = 47.4psi Calculated Stress: f v = 1.46psi Calculated Stress: f v = 6.62psi Confidence Factor: C.F. = 32.5 Confidence Factor: C.F. = 7.2 PAGE 76 64 A3. Exterior CMU Walls â€“ Pier Analysis (Axial & In-Plane Bending): GARAGE "GOAL POST" FRONT ELEVATION P 1 BACK ELEVATION P 2P 1P 2P 3P 4CB 1CB 1CB 2P 6P 5P 4P 3P 2P 1CB 5CB 4CB 3CB 2CB 1 Figure A-3. Piers and coupling beams in the front and back elevations along with the garage â€œgoal postâ€. GARAGE â€œGOAL POSTâ€: Piers #1 and #2 Allowable Moment: M allw = 4971lbf-ft Allowable Shear Stress: F v = 35psi Applied Moment: M = 4121lbf-ft Calculated Shear Stress: f v = 32.4psi Confidence Factor: C.F. = 1.2 Confidence Factor: C.F. = 1.1 GARAGE â€œGOAL POSTâ€: Coupling Beam #1 Allowable Pos. Moment: M allw = 6185lbf-ft Allowable Neg. Moment: M allw = 4732lbf-ft Applied Pos. Moment: M = 3734lbf-ft Applied Neg. Moment: M = 3763lbf-ft Confidence Factor: C.F. = 1.6 Confidence Factor: C.F. = 1.3 Allowable Shear Stress: F v = 38.7psi Calculated Shear Stress: f v = 24.5psi Confidence Factor: C.F. = 1.6 PAGE 77 65 FRONT ELEVATION: Figure A-4 shows the P-M diagram for Pier #1. The applied maximum combination of bending moment and tensile axial load is 5673lbf-ft and 1630lbf, respectively. 0200040006000800011041.21041.41041.61041.81042104 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd1P1'Md1M1'. Figure A-4. Tensile load-moment interaction diagram for pier 1 of the front elevation. 0.1tooMMTP 43.0187645673124001630 ftlbfftlbflbflbf Confidence Factor 3.243.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 14.3psi Confidence Factor: C.F. = 2.4 FRONT ELEVATION: Pier # 2 Allowable Moment: M allw = 14697lbf-ft Allowable Shear Stress: F v = 35psi Applied Moment: M = 2542lbf-ft Calculated Shear Stress: f v = 4.9psi Confidence Factor: C.F. = 5.8 Confidence Factor: C.F. = 7.1 PAGE 78 66 FRONT ELEVATION: Figure A-5 shows the P-M diagram for Pier #3. The applied maximum combination of bending moment and tensile axial load is 3881lbf-ft and 2674lbf, respectively. 0200040006000800011041.21041.41041.6104 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd3P3'Md3M3'. Figure A-5. Tensile load-moment interaction diagram for pier 3 of the front elevation. 0.1tooMMTP 48.0146973881124002674 ftlbfftlbflbflbf Confidence Factor 1.248.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 16.5psi Confidence Factor: C.F. = 2.1 FRONT ELEVATION: Pier # 4 Allowable Moment: M allw = 15276lbf-ft Allowable Shear Stress: F v = 35psi Applied Moment: M = 2886lbf-ft Calculated Shear Stress: f v = 6.2psi Confidence Factor: C.F. = 5.3 Confidence Factor: C.F. = 5.6 PAGE 79 67 FRONT ELEVATION: Figure A-6 shows the P-M diagram for Coupling Beams #1 and #2 (negative bending moment). The maximum combination of applied negative bending moment and tensile axial load is 1850lbf-ft and 771lbf, respectively. 0500100015002000250030003500400045005000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdnTMdnM. Figure A-6. Tensile load-moment (negative) interaction diagram for coupling beams 1 and 2. 0.1tooMMTP 45.04732185012400771ftlbfftlbflbflbf Confidence Factor 2.245.01..FC PAGE 80 68 FRONT ELEVATION: Figure A-7 shows the P-M diagram for Coupling Beams #1 and #2 (positive bending moment). The maximum applied positive bending moment and tensile axial load is 1761lbf-ft and 2120lbf, respectively. 01000200030004000500060007000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdpTMdpM. Figure A-7. Tensile load-moment (positive) interaction diagram for coupling beams 1 and 2. 0.1tooMMTP 46.061851761124002120ftlbfftlbflbflbf Confidence Factor 2.246.01..FC Allowable Shear Stress: F v = 38.7psi Calculated Shear Stress: f v = 16.5psi Confidence Factor: C.F. = 2.3 BACK ELEVATION: Pier # 1 Allowable Moment: M allw = 26971lbf-ft Allowable Shear Stress: F v = 42.8psi Applied Moment: M = 3541lbf-ft Calculated Shear Stress: f v = 7.6psi Confidence Factor: C.F. = 7.6 Confidence Factor: C.F. = 5.6 PAGE 81 69 BACK ELEVATION: Figure A-8 shows the P-M diagram for Pier #2. The maximum combination of applied bending moment and tensile axial load is 1702lbf-ft and 3930lbf, respectively. 0500011041.510421042.5104 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd2P2'Md2M2'. Figure A-8. Tensile load-moment interaction diagram for pier 2 of the back elevation. 0.1tooMMTP 39.0234441702124003930ftlbfftlbflbflbf Confidence Factor 6.239.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 1.4psi Confidence Factor: C.F. = 25 PAGE 82 70 BACK ELEVATION: Figure A-9 shows the P-M diagram for Pier #3. The maximum combination of applied bending moment and tensile axial load is 28lbf-ft and 1034lbf, respectively. 050100150200250300350400450 7000 6000 5000 4000 3000 2000 10000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd3P3'Md3M3'. Figure A-9. Tensile load-moment interaction diagram for pier 3 of the back elevation. 0.1tooMMTP 23.04402862001034ftlbfftlbflbflbf Confidence Factor 3.423.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 1.2psi Confidence Factor: C.F. = 29 PAGE 83 71 BACK ELEVATION: Figure A-10 shows the P-M diagram for Pier #4. The maximum combination of applied bending moment and tensile axial load is 5lbf-ft and 1276lbf, respectively. 050100150200250300350400450 7000 6000 5000 4000 3000 2000 10000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd4P4'Md4M4'. Figure A-10. Tensile load-moment interaction diagram for pier 4 of the back elevation. 0.1tooMMTP 22.0440562001276ftlbfftlbflbflbf Confidence Factor 5.422.01..FC Allowable Shear Stress: F v = N/A Calculated Shear Stress: f v = 0psi Confidence Factor: C.F. = N/A PAGE 84 72 BACK ELEVATION: Figure A-11 shows the P-M diagram for Pier #5. The maximum combination of applied bending moment and tensile axial load is 32lbf-ft and 1426lbf, respectively. 02004006008001000 7000 6000 5000 4000 3000 2000 10000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd5P5'Md5M5'. Figure A-11. Tensile load-moment interaction diagram for pier 5 of the back elevation. 0.1tooMMTP 26.09903262001426ftlbfftlbflbflbf Confidence Factor 8.326.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 0.5psi Confidence Factor: C.F. = 70 BACK ELEVATION: Pier # 6 Allowable Moment: M allw = 85898lbf-ft Allowable Shear Stress: F v = 35psi Applied Moment: M = 43490lbf-ft Calculated Shear Stress: f v = 3.4psi Confidence Factor: C.F. = 2.0 Confidence Factor: C.F. = 10.3 PAGE 85 73 BACK ELEVATION: Figure A-12 shows the P-M diagram of Coupling Beams #1 thru #5 (negative bending moment). The maximum combination of applied negative bending moment and tensile axial load is 3241lbf-ft and 3810lbf, respectively. 0500100015002000250030003500400045005000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdnTMdnM. Figure A-12. Tensile load-moment (negative) interaction diagram for coupling beams 1 through 5 0.1tooMMTP 99.047323241124003810ftlbfftlbflbflbf Confidence Factor 01.199.01..FC PAGE 86 74 BACK ELEVATION: Figure A-13 shows the P-M diagram of Coupling Beams #1 thru #5 (positive bending moment). The maximum combination of applied positive bending moment and tensile axial load is 1498lbf-ft and 2056lbf, respectively. 01000200030004000500060007000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdpTMdpM. Figure A-13. Tensile load-moment (positive) interaction diagram for coupling beams 1 through 5. 0.1tooMMTP 41.061851498124002056 ftlbfftlbflbflbf Confidence Factor 4.241.01..FC Allowable Shear Stress: F v = 38.7psi Calculated Shear Stress: f v = 22.6psi Confidence Factor: C.F. = 1.7 PAGE 87 75 A4. Bond Beam (single top course): The flexural and shear capacity of the bond beam along with the vertical reinforcement and anchorage capacity has been determined and the calculated stresses are compared to the stresses caused by the applied loads as described below. RIGHT ELEVATION: Approximately 55% of the bond beam in the right elevation fails due to either positive or negative bending. LEFT ELEVATION: Approximately 54% of the bond beam in the left elevation fails due to positive bending, negative bending, shear forces, and anchorage withdrawal. BACK ELEVATION: Approximately 37% of the bond beam in the back elevation fails due to positive bending, negative bending, shear forces, and anchorage withdrawal. FRONT ELEVATION: (Not including garage â€œgoal postâ€ since no load is applied there.) Approximately 38% of the bond beam in the front elevation fails due to positive bending, negative bending, shear forces, and anchorage withdrawal. GARAGE SIDEWALL: Approximately 59% of the bond beam in the garage sidewall fails due to positive bending, negative bending, and shear forces. GARAGE "GOAL POST" FRONT ELEVATION BACK ELEVATION GARAGE SIDEWALLRIGHT ELEVATIONLEFT ELEVATION Max. + Moment Max. Moment Max. Shear Max. SupportReaction Figure A-14. Shaded areas approximately show the sections of bond beam that fail. PAGE 88 76 FLEXURE: Maximum Applied Positive Bending Moment Allowable Stress: Masonry F b = 500psi Steel F s = 20,000psi Calculated Stress: Masonry b = 4249psi Steel s = 91090psi Confidence Factor: Masonry C.F. = 0.12 Steel C.F. = 0.22 FLEXURE: Maximum Applied Negative Bending Moment Allowable Stress: Masonry F b = 500psi Steel F s = 20,000psi Calculated Stress: Masonry b = 700psi Steel s = 22734psi Confidence Factor: Masonry C.F. = 0.71 Steel C.F. = 0.88 SHEAR: Maximum Applied Shear Force Allowable Stress: F v = 39psi Calculated Stress: f v = 91psi Confidence Factor: C.F. = 0.43 SUPPORT REACTION: Maximum Force Applied to Vertical Reinforcement Allowable Stress: F s = 20,000psi Calculated Stress: s = 18103psi Confidence Factor: C.F. = 1.1 SUPPORT REACTION: Maximum Force Applied to Anchorage Allowable Stress: F anchr = 20000psi Calculated Stress: s = 18103psi Confidence Factor: C.F. = 1.1 PAGE 89 77 A5. Precast (span 16ft) and Prestressed (span 16ft) Lintels: span = 4.5ftspan = 16ftspan = 6.33ftspan = 6.33ft span = 4.5ftspan = 6.0ftspans = 4.5ft Max. Moment 4.5 spanMax. Moment 6.33 span Max. Moment 16 spanMax. Shear Figure A-15. Location of critical lintels in the project structure. LINTEL: Spans of 4.5ft LINTEL: Spans of 6.0ft-6.33ft Allowable Moment M allw = 9531lbf-ft Allowable Moment M allw = 10542lbf-ft Applied Moment M = 6185lbf-ft Applied Moment M = 5117lbf-ft Confidence Factor: C.F. = 1.5 Confidence Factor: C.F. = 2.0 LINTEL: Spans of 16ft ALL LINTELS Allowable Moment M allw = 29250lbf-ft Allowable Shear Stress F v = 38.7psi Applied Moment M = 6902lbf-ft Calculated Shear Stress f v = 32.1psi Confidence Factor: C.F. = 4.2 Confidence Factor: C.F. = 1.2 PAGE 90 78 A6. Back Trussed Porch/Front Entry/ Interior Load Bearing Wall: FRONT ENTRYINTERIOR LOAD BEARING WALLBACK TRUSSED PORCH Figure A-16: Location of the back trussed porch, front entry, and interior load bearing wall. BACK TRUSSED PORCH: The Confidence Factors for the timber headers and masonry columns that frame the back porch are as follows: 2 2x12 HEADERS â€“ DOWNWARD FORCES 2 2x12 HEADERS â€“ UPLIFT FORCES Allowable Bending Stress F b = 1219psi Allowable Bending Stress F b = 1560psi Calculated Bending Stress b = 754psi Calculated Bending Stress b = 594psi Confidence Factor: C.F. = 1.6 Confidence Factor: C.F. = 2.6 2 â€“ 2x12 HEADERS Allowable Shear Stress F v = 113psi Calculated Shear Stress f v = 69psi Confidence Factor: C.F. = 1.6 PAGE 91 79 CMU COLUMNS â€“ DOWNWARD FORCES Allowable Compressive Axial Load P allw = 42666lbf Applied Compressive Axial Load P = 3640lbf Confidence Factor: C.F. = 11.7 CMU COLUMNS â€“ UPLIFT FORCES: Allowable Tensile Axial Load P allw = 6200lbf Applied Tensile Axial Load P = 1839lbf Confidence Factor: C.F. = 3.4 FRONT ENTRY: The Confidence Factors for the timber headers and masonry columns that frame the front entry are as follows: 2 2x8 HEADERS â€“ DOWNWARD FORCES Allowable Bending Stress F b = 1500psi Allowable Shear Stress F v = 113psi Calculated Bending Stress b = 330psi Calculated Shear Stress f v = 25psi Confidence Factor: C.F. = 4.5 Confidence Factor: C.F. = 4.5 2 2x8 HEADERS â€“ UPLIFT FORCES Allowable Bending Stress F b = 1920psi Allowable Shear Stress F v = 144psi Calculated Bending Stress b = 240psi Calculated Shear Stress f v = 18psi Confidence Factor: C.F. = 8.0 Confidence Factor: C.F. = 8.0 CMU COLUMNS â€“ DOWNWARD FORCES Allowable Compressive Axial Load P allw = 88625lbf Applied Compressive Axial Load P = 3205lbf Confidence Factor: C.F. = 28 CMU COLUMNS â€“ UPLIFT FORCES Allowable Tensile Axial Load P allw = 24800lbf Applied Tensile Axial Load P = 622lbf Confidence Factor: C.F. = 40 PAGE 92 80 INTERIOR LOAD BEARING WALL: DOUBLE TOP PLATE â€“ DOWNWARD FORCES Allowable Bending Stress F b = 2063psi Allowable Shear Stress F v = 113psi Calculated Bending Stress b = 1281psi Calculated Shear Stress f v = 180psi Confidence Factor: C.F. = 1.6 Confidence Factor: C.F. = 0.63 DOUBLE TOP PLATE â€“ UPLIFT FORCES Allowable Bending Stress F b = 2640psi Allowable Shear Stress Fv = 144psi Calculated Bending Stress b = 1479psi Calculated Shear Stress fv = 208psi Confidence Factor: C.F. = 1.8 Confidence Factor: C.F. = 0.70 2x4 VERTICAL STUD â€“ DOWNWARD FORCES Allowable Axial Compressive Stress F b = 644psi Calculated Axial Compressive Stress b = 663psi Confidence Factor: C.F. = 0.97 2x4 VERTICAL STUD â€“ UPLIFT FORCES Allowable Axial Tensile Stress F b = 1063psi Calculated Axial Tensile Stress b = 680psi Confidence Factor: C.F. = 1.6 J-BOLT CONNECTIONS Allowable Connection Load (based on crushing stress of wood) P allw = 996lbf Applied Connection Load (maximum of two design checks) P = 1521lbf Confidence Factor: C.F. = 0.65 PAGE 93 81 A7. Doors and Window Anchorage/Roof Sheathing: Door/Sliding Glass Door, Window, and Garage Door Anchorage: WINDOW ANCHORAGE â€“ TapCon CONNECTION Allowable Shear Load V allw = 255lbf Applied Shear Load V = 213lbf Confidence Factor: C.F. = 1.2 DOOR/SLIDING GLASS DOOR ANCHORAGE â€“ TapCon CONNECTION Allowable Shear Load V allw = 255lbf Applied Shear Load V = 242lbf Confidence Factor: C.F. = 1.0 GARAGE DOOR ANCHORAGE â€“ J-BOLT CONNECTION Allowable Connection Load (based on crushing stress of wood) P allw = 996lbf Applied Connection Load P = 694lbf Roof Sheathing: Due to the applied wind pressure, the sheathing was checked for bending, shear, and deflection. SHEATHING Allowable Wind Pressure (with allowable stresses for bending and shear) p allw = 117psf Applied Design Wind Pressure p w = 106 Confidence Factor: C.F. = 1.1 NAIL WITHDRAWAL Allowable Uplift Force Per Nail P allw = 98.4lbf Applied Uplift Force Per Nail P u = 76lbf Confidence Factor: C.F. = 1.3 PAGE 94 82 A8. Connections (truss-to-bond beam, back trussed porch, front entry): See Tables A-1 through A-3 for all calculated Confidence Factors. LEFT ELEVATION: Confidence Factor: C.F. = 1.2 RIGHT ELEVATION: Confidence Factor: C.F. = 2.2 GARAGE SIDEWALL: Confidence Factor: C.F. = 1.2 FRONT ELEVATION: Confidence Factor: C.F. = 0.98 BACK ELEVATION: Confidence Factor: C.F. = 0.64 BACK TRUSSED PORCH: Confidence Factor: C.F. = 1.3 FRONT ENTRY: Confidence Factor: C.F. = 1.5 Table A-1. Confidence factors for the truss-to-bond beam anchors. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss ( lb ) Anchor IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionLeft ElevationT2GE281101Hughes/TA1811694.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT21002101Hughes/TA1811691.2OKLeft ElevationAT2A1009101Hughes/TA1811691.2OKLeft ElevationAT2A1009101Hughes/TA1811691.2OKLeft ElevationAT2A1009101Hughes/TA1811691.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OK PAGE 95 83 Table A-1 cont. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss ( lb ) Anchor IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationJ8532101Hughes/TA1811692.2OKLeft ElevationBJ6476101Hughes/TA1811692.5OKLeft ElevationBJ4395101Hughes/TA1811693.0OKLeft ElevationBJ2291101Hughes/TA1811694.0OKCorner of Left and Back Elev.CJ8412101Hughes/TA1811692.8OKBack ElevationBJ2291101Hughes/TA1811694.0OKBack ElevationBJ4395101Hughes/TA1811693.0OKBack ElevationBJ6476101Hughes/TA1811692.5OKBack ElevationMH81S3409102Hughes/ (2) TA1823380.7Back ElevationH101S1640101Hughes/TA1811690.7Back ElevationH121S1675101Hughes/TA1811690.7Back ElevationH141S1122101Hughes/TA1811691.0OKBack ElevationH161S1746101Hughes/TA1811690.7Back ElevationH181S1098101Hughes/TA1811691.1OKBack ElevationSH201S1631101Hughes/TA1811690.7Back ElevationS11010101Hughes/TA1811691.2OKBack ElevationS11010101Hughes/TA1811691.2OKBack ElevationS11010101Hughes/TA1811691.2OKBack ElevationS11010101Hughes/TA1811691.2OKBack ElevationSH201A1023101Hughes/TA1811691.1OKBack ElevationSH181SP986101Hughes/TA1811691.2OKBack ElevationSH161SP999101Hughes/TA1811691.2OKBack ElevationSH141SP1638101Hughes/TA1811690.7Back ElevationH1211585101Hughes/TA1811690.7Back ElevationH1011834101Hughes/TA1811690.6Back ElevationH813811104Hughes/ (2) HTA2040001.0OKBack ElevationBJ6476101Hughes/TA1811692.5OKBack ElevationBJ4395101Hughes/TA1811693.0O K Back ElevationBJ2291101Hughes/TA1811694.0OKCorner of Back and Right Elev.CJ8412101Hughes/TA1811692.8OKRight ElevationBJ2291101Hughes/TA1811694.0OKRight ElevationBJ4395101Hughes/TA1811693.0OKRight ElevationBJ6476101Hughes/TA1811692.5OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OK FAILSFAILSFAILSFAILSFAILSFAILSFAILSFAILS PAGE 96 84 Table A-1 cont. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss ( lb ) Anchor IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationJ8532101Hughes/TA1811692.2OKRight ElevationBJ6476101Hughes/TA1811692.5OKRight ElevationBJ4395101Hughes/TA1811693.0OKRight ElevationBJ2291101Hughes/TA1811694.0OKCorner of Right and Front Elev.CJ8412101Hughes/TA1811692.8OKFront ElevationBJ2291101Hughes/TA1811694.0OKFront ElevationBJ4395101Hughes/TA1811693.0OKFront ElevationBJ6476101Hughes/TA1811692.5OKFront ElevationH813493104Hughes/ (2) HTA2040001.1OKFront ElevationH1011834101Hughes/TA1811690.6Front ElevationH1211537101Hughes/TA1811690.8Front ElevationSH141SP1568101Hughes/TA1811690.7Front ElevationSH161SP1043101Hughes/TA1811691.1OKFront ElevationSH181SP1029101Hughes/TA1811691.1OKFront ElevationSH201A1209101Hughes/TA1811691.0Front ElevationS11196101Hughes/TA1811691.0Front ElevationS11196101Hughes/TA1811691.0Front ElevationS11196101Hughes/TA1811691.0Front ElevationS11196101Hughes/TA1811691.0Front ElevationJG5601022101Hughes/TA1811691.1OKGarage Side WallAT21002101Hughes/TA1811691.2OKGarage Side WallAT31002101Hughes/TA1811691.2OKGarage Side WallAT41002101Hughes/TA1811691.2OKGarage Side WallAT51002101Hughes/TA1811691.2OKGarage Side WallAT91002101Hughes/TA1811691.2OKGarage Side WallAT101002101Hughes/TA1811691.2OKGarage Side WallT2GE281101Hughes/TA1811694.2OK FAILSFAILSFAILSFAILSFAILSFAILSFAILSFAILS PAGE 97 85 Table A-2. Confidence factors for the anchors/connectors of the back trussed porch. A) Truss-to-header connection. B) Header-to-bond beam and column connections. Connection DescriptionTruss IDMaximum Uplift Reaction of Truss ( lb ) Connection IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionTruss-to-headerT19GE629603Hughes/ LSTA18*12702.0OKTruss-to-headerT19629603Hughes/HC1010121.6OKTruss-to-headerT19629603Hughes/HC1010121.6OKTruss-to-headerT19629603Hughes/HC1010121.6OKTruss-to-headerT19629603Hughes/HC1010121.6OKTruss-to-headerT19629603Hughes/HC1010121.6OKTruss-to-headerT19629603Hughes/HC1010121.6OKConnection DescriptionGravity Reaction (lb)Uplift Reaction (lb)Manufacturer Part No.Capacity Gravity (lb)Capacity Uplift (lb)C.F.ConclusionHeader-to-bond beam23071839Hughes/NFM 35x12U595534501.9OKHeader-to-columnNot Critical1839Hughes/ HTA20Not Critical23751.3OKA)* Construction plans actually call out Hughes RT18112. The capacity of this connection is no longer available in the USP catalog. Therefore, the connection used in Project Structure No. 2 was used.B) Table A-3. Confidence factors for the anchors/connectors of the front entry. A) Truss-to-header connection. B) Header-tocolumn connections. Connection DescriptionTruss IDMaximum Uplift Reaction of Truss ( lb ) Connection IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionTruss-to-heade r T3GE1206N/AHughes/HCDP4950.4FAILSTruss-to-heade r T31206N/AHughes/HCDP4950.4FAILSTruss-to-heade r T31206N/AHughes/HCDP4950.4FAILSConnection DescriptionGravity Reaction (lb)Uplift Reaction (lb)Manufacturer Part No.Capacity Gravity (lb)Capacity Uplift (lb)C.F.ConclusionHeader-to-columnNot Critical2394Hughes/TA18Not Critical11690.5FAILSB)A) PAGE 98 APPENDIX B EVALUATION SUMMARY OF STRUCTURE NO. 2 IMPROVED CMU HOME A Confidence Factor (C.F.) has been given to each element and is defined as the allowable stress divided by the calculated stress. Any element possessing a C.F. greater than or equal to 1.0 is considered safe and no immediate design improvements are necessary. If a particular element has a C.F. less than 1.0, the calculated stress exceeds the allowable stress and immediate design improvements may be necessary. The C.F. (as defined in this study) is not to be confused with a Factor of Safety (F.S.). A F.S. was already incorporated in the allowable stress of the structural materials and hence included in the calculation of the C.F. The following Sections A1 through A8 summarize the analytical evaluation of Structure 2 giving the minimum confidence factor for each major element that makes up the Main Wind Force Resisting System (MWFRS) and the Components and Cladding (C&C). 86 PAGE 99 87 B1. Exterior CMU Walls (Axial & Out-of-Plane Bending): New design check conducted. Figure B-1 shows the P-M diagram for the 8â€ pier in the back elevation. The critical combination of applied bending moment and tensile axial load is 1704lbf-ft and 324lbf, respectively. 05001000150020001104210431044104 P-M Diagram Moment (lbf-ft)Load (lbf)PdPeulerPloadsMdMeulerMloads Figure B-1. Load-moment interaction diagram for 8â€ pier in the back elevation. 0.1tooMMTP 35.1129717048267324 ftlbfftlbflbflbf Confidence Factor 74.035.11..F C PAGE 100 88 Figure B-2 shows the P-M diagram for the most critical wall section located in the left elevation. The critical combination of applied bending moment and axial load is 2175lbf-ft and 314lbf, respectively. 010002000300040005000600070008000900021044104610481041105 P-M Diagram Moment (lbf-ft)Load (lbf)PdPeulerPloadsMdMeulerMloads Figure B-2. Load-moment interaction diagram for most critical wall section in left elevation Confidence Factor 0.11)2/(2/tocotooMMMMPP 04.10.12420)9350(2420217554201314.. ftlbfftlbfftlbfftlbflbflbfFC PAGE 101 89 Figure B-3 shows the P-M diagram for the 8â€ supporting the load transferred from the critical window in the front elevation. The critical combination of applied bending moment and tensile axial load is 1112lbf-ft and 174lbf, respectively. 0500100015002000110421043104 P-M Diagram Moment (lbf-ft)Load (lbf)PdPeulerPloadsMdMeulerMloads Figure B-3. Load-moment interaction diagram for 8â€ pier in the front elevation 0.1tooMMTP 86.0133311128267174 ftlbfftlbflbflbf Confidence Factor 16.186.01..F C PAGE 102 90 B2. Exterior CMU Walls Shear Walls (Axial & In-Plane Bending): The shear walls of the project structure are more than sufficient to resist the applied lateral forces. RIGHT ELEVATION LEFT ELEVATIONSW 1SW 2SW 3SW 4SW 2SW 1GARAGE SIDEWALL Figure B-4. Shear wall locations in the right and left elevations along with the garage sidewall. LEFT ELEVATION: Shear Wall #1 RIGHT ELEVATION: Shear Wall #1 Allowable Stress: F v = 41.64psi Allowable Stress: F v = 40.2psi Calculated Stress: f v = 0.24psi Calculated Stress: f v = 2.0psi Confidence Factor: C.F. = 51.2 Confidence Factor: C.F. = 20.1 LEFT ELEVATION: Shear Wall #2 RIGHT ELEVATION: Shear Wall #2 Allowable Stress: F v = 38.9psi Allowable Stress: F v = 39.99psi Calculated Stress: f v = 0.76psi Calculated Stress: f v = 2.73psi Confidence Factor: C.F. = 173.5 Confidence Factor: C.F. = 14.6 LEFT ELEVATION: Shear Wall #3 Allowable Stress: F v = 38.9psi Calculated Stress: f v = 1.13psi Confidence Factor: C.F. = 34.4 LEFT ELEVATION: Shear Wall #4 GARAGE SIDEWALL: Allowable Stress: F v = 47.4psi Allowable Stress: F v = 47.4psi Calculated Stress: f v = 1.46psi Calculated Stress: f v = 6.62psi Confidence Factor: C.F. = 32.5 Confidence Factor: C.F. = 7.2 PAGE 103 91 B3. Exterior CMU Walls â€“ Pier Analysis (Axial & In-Plane Bending): GARAGE "GOAL POST" FRONT ELEVATION P 1 BACK ELEVATION P 2P 1P 2P 3P 4CB 1CB 1CB 2P 6P 5P 4P 3P 2P 1CB 5CB 4CB 3CB 2CB 1 Figure B-5. Piers and coupling beams in the front and back elevations along with the garage â€œgoal postâ€. GARAGE â€œGOAL POSTâ€: Piers #1 and #2 Allowable Moment: M allw = 4971lbf-ft Allowable Shear Stress: F v = 35psi Applied Moment: M = 4121lbf-ft Calculated Shear Stress: f v = 32.4psi Confidence Factor: C.F. = 1.2 Confidence Factor: C.F. = 1.1 GARAGE â€œGOAL POSTâ€: Coupling Beam #1 Allowable Pos. Moment: M allw = 6185lbf-ft Allowable Neg. Moment: M allw = 4732lbf-ft Applied Pos. Moment: M = 3734lbf-ft Applied Neg. Moment: M = 3763lbf-ft Confidence Factor: C.F. = 1.6 Confidence Factor: C.F. = 1.3 Allowable Shear Stress: F v = 38.7psi Calculated Shear Stress: f v = 24.5psi Confidence Factor: C.F. = 1.6 PAGE 104 92 FRONT ELEVATION: Figure B-6 shows the P-M diagram for Pier #1. The applied maximum combination of bending moment and tensile axial load is 5673lbf-ft and 1630lbf, respectively. 0200040006000800011041.21041.41041.61041.81042104 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd1P1'Md1M1'. Figure B-6. Tensile load-moment interaction diagram for pier 1 of the front elevation. 0.1tooMMTP 43.0187645673124001630 ftlbfftlbflbflbf Confidence Factor 3.243.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 14.3psi Confidence Factor: C.F. = 2.4 FRONT ELEVATION: Pier # 2 Allowable Moment: M allw = 14697lbf-ft Allowable Shear Stress: F v = 35psi Applied Moment: M = 2542lbf-ft Calculated Shear Stress: f v = 4.9psi Confidence Factor: C.F. = 5.8 Confidence Factor: C.F. = 7.1 PAGE 105 93 FRONT ELEVATION: Figure B-7 shows the P-M diagram for Pier #3. The applied maximum combination of bending moment and tensile axial load is 3881lbf-ft and 2674lbf, respectively. 0200040006000800011041.21041.41041.6104 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd3P3'Md3M3'. Figure B-7. Tensile load-moment interaction diagram for pier 3 of the front elevation. 0.1tooMMTP 48.0146973881124002674 ftlbfftlbflbflbf Confidence Factor 1.248.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 16.5psi Confidence Factor: C.F. = 2.1 FRONT ELEVATION: Pier # 4 Allowable Moment: M allw = 15276lbf-ft Allowable Shear Stress: F v = 35psi Applied Moment: M = 2886lbf-ft Calculated Shear Stress: f v = 6.2psi Confidence Factor: C.F. = 5.3 Confidence Factor: C.F. = 5.6 PAGE 106 94 FRONT ELEVATION: Figure B-8 shows the P-M diagram for Coupling Beams #1 and #2 (negative bending moment). The maximum combination of applied negative bending moment and tensile axial load is 1850lbf-ft and 771lbf, respectively. 0500100015002000250030003500400045005000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdnTMdnM. Figure B-8. Tensile load-moment (negative) interaction diagram for coupling beams 1 and 2. 0.1tooMMTP 45.04732185012400771ftlbfftlbflbflbf Confidence Factor 2.245.01..FC PAGE 107 95 FRONT ELEVATION: Figure B-9 shows the P-M diagram for Coupling Beams #1 and #2 (positive bending moment). The maximum applied positive bending moment and tensile axial load is 1761lbf-ft and 2120lbf, respectively. 01000200030004000500060007000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdpTMdpM. Figure B-9. Tensile load-moment (positive) interaction diagram for coupling beams 1 and 2. 0.1tooMMTP 46.061851761124002120ftlbfftlbflbflbf Confidence Factor 2.246.01..FC Allowable Shear Stress: F v = 38.7psi Calculated Shear Stress: f v = 16.5psi Confidence Factor: C.F. = 2.3 BACK ELEVATION: Pier # 1 Allowable Moment: M allw = 26971lbf-ft Allowable Shear Stress: F v = 42.8psi Applied Moment: M = 3541lbf-ft Calculated Shear Stress: f v = 7.6psi Confidence Factor: C.F. = 7.6 Confidence Factor: C.F. = 5.6 PAGE 108 96 BACK ELEVATION: Figure B-10 shows the P-M diagram for Pier #2. The maximum combination of applied bending moment and tensile axial load is 1702lbf-ft and 3930lbf, respectively. 0500011041.510421042.5104 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd2P2'Md2M2'. Figure B-10. Tensile load-moment interaction diagram for pier 2 of the back elevation. 0.1tooMMTP 39.0234441702124003930ftlbfftlbflbflbf Confidence Factor 6.239.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 1.4psi Confidence Factor: C.F. = 25 PAGE 109 97 BACK ELEVATION: Figure B-11 shows the P-M diagram for Pier #3. The maximum combination of applied bending moment and tensile axial load is 28lbf-ft and 1034lbf, respectively. 050100150200250300350400450 7000 6000 5000 4000 3000 2000 10000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd3P3'Md3M3'. Figure B-11. Tensile load-moment interaction diagram for pier 3 of the back elevation. 0.1tooMMTP 23.04402862001034ftlbfftlbflbflbf Confidence Factor 3.423.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 1.2psi Confidence Factor: C.F. = 29 PAGE 110 98 BACK ELEVATION: Figure B-12 shows the P-M diagram for Pier #4. The maximum combination of applied bending moment and tensile axial load is 5lbf-ft and 1276lbf, respectively. 050100150200250300350400450 7000 6000 5000 4000 3000 2000 10000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd4P4'Md4M4'. Figure B-12. Tensile load-moment interaction diagram for pier 4 of the back elevation. 0.1tooMMTP 22.0440562001276ftlbfftlbflbflbf Confidence Factor 5.422.01..FC Allowable Shear Stress: F v = N/A Calculated Shear Stress: f v = 0psi Confidence Factor: C.F. = N/A PAGE 111 99 BACK ELEVATION: Figure B-13 shows the P-M diagram for Pier #5. The maximum combination of applied bending moment and tensile axial load is 32lbf-ft and 1426lbf, respectively. 02004006008001000 7000 6000 5000 4000 3000 2000 10000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd5P5'Md5M5'. Figure B-13. Tensile load-moment interaction diagram for pier 5 of the back elevation. 0.1tooMMTP 26.09903262001426ftlbfftlbflbflbf Confidence Factor 8.326.01..FC Allowable Shear Stress: F v = 35psi Calculated Shear Stress: f v = 0.5psi Confidence Factor: C.F. = 70 BACK ELEVATION: Pier # 6 Allowable Moment: M allw = 85898lbf-ft Allowable Shear Stress: F v = 35psi Applied Moment: M = 43490lbf-ft Calculated Shear Stress: f v = 3.4psi Confidence Factor: C.F. = 2.0 Confidence Factor: C.F. = 10.3 PAGE 112 100 BACK ELEVATION: Figure B-14 shows the P-M diagram of Coupling Beams #1 thru #5 (negative bending moment). The maximum combination of applied negative bending moment and tensile axial load is 3241lbf-ft and 3810lbf, respectively. 0500100015002000250030003500400045005000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdnTMdnM. Figure B-14. Tensile load-moment (negative) interaction diagram for coupling beams 1 through 5 0.1tooMMTP 99.047323241124003810ftlbfftlbflbflbf Confidence Factor 01.199.01..FC PAGE 113 101 BACK ELEVATION: Figure B-15 shows the P-M diagram of Coupling Beams #1 thru #5 (positive bending moment). The maximum combination of applied positive bending moment and tensile axial load is 1498lbf-ft and 2056lbf, respectively. 01000200030004000500060007000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdpTMdpM. Figure B-15. Tensile load-moment (positive) interaction diagram for coupling beams 1 through 5. 0.1tooMMTP 41.061851498124002056 ftlbfftlbflbflbf Confidence Factor 4.241.01..FC Allowable Shear Stress: F v = 38.7psi Calculated Shear Stress: f v = 22.6psi Confidence Factor: C.F. = 1.7 PAGE 114 102 B4. Bond Beam (single top course): New design check conducted. The flexural and shear capacity of the bond beam along with the vertical reinforcement and anchorage capacity has been determined and the calculated stresses are compared to the stresses caused by the applied loads as described below. RIGHT ELEVATION: Less than 1% of the bond beam in the right elevation fails due to positive bending. LEFT ELEVATION: Approximately 25% of the bond beam in the left elevation fails due to positive bending, negative bending, shear forces, and anchorage withdrawal. BACK ELEVATION: Approximately 30% of the bond beam in the back elevation fails due to positive bending, negative bending, shear forces, and anchorage withdrawal. FRONT ELEVATION: (Not including garage â€œgoal postâ€ since no load is applied there.) Approximately 38% of the bond beam in the front elevation fails due to positive bending, negative bending, shear forces, and anchorage withdrawal. GARAGE SIDEWALL: Approximately 59% of the bond beam in the garage sidewall fails due to positive bending, negative bending, and shear forces. GARAGE "GOAL POST" FRONT ELEVATION BACK ELEVATION GARAGE SIDEWALLRIGHT ELEVATIONLEFT ELEVATION Max. + Moment Max. Moment Max. Shear Max. SupportReaction Figure B-16. Shaded areas approximately show the sections of bond beam that fail. PAGE 115 103 FLEXURE: Maximum Applied Positive Bending Moment Allowable Stress: Masonry F b = 500psi Steel F s = 20,000psi Calculated Stress: Masonry b = 3574psi Steel s = 76625psi Confidence Factor: Masonry C.F. = 0.14 Steel C.F. = 0.26 FLEXURE: Maximum Applied Negative Bending Moment Allowable Stress: Masonry F b = 500psi Steel F s = 20,000psi Calculated Stress: Masonry b = 562psi Steel s = 18243psi Confidence Factor: Masonry C.F. = 0.89 Steel C.F. = 1.1 SHEAR: Maximum Applied Shear Force Allowable Stress: F v = 39psi Calculated Stress: f v = 91psi Confidence Factor: C.F. = 0.43 SUPPORT REACTION: Maximum Force Applied to Vertical Reinforcement Allowable Stress: F s = 20,000psi Calculated Stress: s = 18103psi Confidence Factor: C.F. = 1.1 SUPPORT REACTION: Maximum Force Applied to Anchorage Allowable Stress: F anchr = 20000psi Calculated Stress: s = 18103psi Confidence Factor: C.F. = 1.1 PAGE 116 104 B5. Precast (span 16ft) and Prestressed (span 16ft) Lintels: span = 4.5ftspan = 16ftspan = 6.33ftspan = 6.33ft span = 4.5ftspan = 6.0ftspans = 4.5ft Max. Moment 4.5 spanMax. Moment 6.33 span Max. Moment 16 spanMax. Shear Figure B-17. Location of critical lintels in the project structure. LINTEL: Spans of 4.5ft LINTEL: Spans of 6.0ft-6.33ft Allowable Moment M allw = 9531lbf-ft Allowable Moment M allw = 10542lbf-ft Applied Moment M = 6185lbf-ft Applied Moment M = 5117lbf-ft Confidence Factor: C.F. = 1.5 Confidence Factor: C.F. = 2.0 LINTEL: Spans of 16ft ALL LINTELS Allowable Moment M allw = 29250lbf-ft Allowable Shear Stress F v = 38.7psi Applied Moment M = 6902lbf-ft Calculated Shear Stress f v = 32.1psi Confidence Factor: C.F. = 4.2 Confidence Factor: C.F. = 1.2 PAGE 117 105 B6. Back Trussed Porch/Front Entry/ Interior Load Bearing Wall: FRONT ENTRYINTERIOR LOAD BEARING WALLBACK TRUSSED PORCH Figure B-18: Location of the back trussed porch, front entry, and interior load bearing wall. BACK TRUSSED PORCH: The Confidence Factors for the timber headers and masonry columns that frame the back porch are as follows: 2 2x12 HEADERS â€“ DOWNWARD FORCES 2 2x12 HEADERS â€“ UPLIFT FORCES Allowable Bending Stress F b = 1219psi Allowable Bending Stress F b = 1560psi Calculated Bending Stress b = 754psi Calculated Bending Stress b = 594psi Confidence Factor: C.F. = 1.6 Confidence Factor: C.F. = 2.6 2 â€“ 2x12 HEADERS Allowable Shear Stress F v = 113psi Calculated Shear Stress f v = 69psi Confidence Factor: C.F. = 1.6 PAGE 118 106 CMU COLUMNS â€“ DOWNWARD FORCES Allowable Compressive Axial Load P allw = 42666lbf Applied Compressive Axial Load P = 3640lbf Confidence Factor: C.F. = 11.7 CMU COLUMNS â€“ UPLIFT FORCES: Allowable Tensile Axial Load P allw = 6200lbf Applied Tensile Axial Load P = 1839lbf Confidence Factor: C.F. = 3.4 FRONT ENTRY: The Confidence Factors for the timber headers and masonry columns that frame the front entry are as follows: 2 2x8 HEADERS â€“ DOWNWARD FORCES Allowable Bending Stress F b = 1500psi Allowable Shear Stress F v = 113psi Calculated Bending Stress b = 330psi Calculated Shear Stress f v = 25psi Confidence Factor: C.F. = 4.5 Confidence Factor: C.F. = 4.5 2 2x8 HEADERS â€“ UPLIFT FORCES Allowable Bending Stress F b = 1920psi Allowable Shear Stress F v = 144psi Calculated Bending Stress b = 240psi Calculated Shear Stress f v = 18psi Confidence Factor: C.F. = 8.0 Confidence Factor: C.F. = 8.0 CMU COLUMNS â€“ DOWNWARD FORCES Allowable Compressive Axial Load P allw = 88625lbf Applied Compressive Axial Load P = 3205lbf Confidence Factor: C.F. = 28 CMU COLUMNS â€“ UPLIFT FORCES Allowable Tensile Axial Load P allw = 24800lbf Applied Tensile Axial Load P = 622lbf Confidence Factor: C.F. = 40 PAGE 119 107 INTERIOR LOAD BEARING WALL: DOUBLE TOP PLATE â€“ DOWNWARD FORCES Allowable Bending Stress F b = 2063psi Allowable Shear Stress F v = 113psi Calculated Bending Stress b = 1281psi Calculated Shear Stress f v = 180psi Confidence Factor: C.F. = 1.6 Confidence Factor: C.F. = 0.63 DOUBLE TOP PLATE â€“ UPLIFT FORCES Allowable Bending Stress F b = 2640psi Allowable Shear Stress Fv = 144psi Calculated Bending Stress b = 1479psi Calculated Shear Stress fv = 208psi Confidence Factor: C.F. = 1.8 Confidence Factor: C.F. = 0.70 2x4 VERTICAL STUD â€“ DOWNWARD FORCES Allowable Axial Compressive Stress F b = 644psi Calculated Axial Compressive Stress b = 663psi Confidence Factor: C.F. = 0.97 2x4 VERTICAL STUD â€“ UPLIFT FORCES Allowable Axial Tensile Stress F b = 1063psi Calculated Axial Tensile Stress b = 680psi Confidence Factor: C.F. = 1.6 J-BOLT CONNECTIONS Allowable Connection Load (based on crushing stress of wood) P allw = 996lbf Applied Connection Load (maximum of two design checks) P = 1521lbf Confidence Factor: C.F. = 0.65 PAGE 120 108 B7. Doors and Window Anchorage/Roof Sheathing: Door/Sliding Glass Door, Window, and Garage Door Anchorage: WINDOW ANCHORAGE â€“ TapCon CONNECTION Allowable Shear Load V allw = 255lbf Applied Shear Load V = 213lbf Confidence Factor: C.F. = 1.2 DOOR/SLIDING GLASS DOOR ANCHORAGE â€“ TapCon CONNECTION Allowable Shear Load V allw = 255lbf Applied Shear Load V = 242lbf Confidence Factor: C.F. = 1.0 GARAGE DOOR ANCHORAGE â€“ J-BOLT CONNECTION Allowable Connection Load (based on crushing stress of wood) P allw = 996lbf Applied Connection Load P = 694lbf Roof Sheathing: Due to the applied wind pressure, the sheathing was checked for bending, shear, and deflection. SHEATHING Allowable Wind Pressure (with allowable stresses for bending and shear) p allw = 117psf Applied Design Wind Pressure p w = 106 Confidence Factor: C.F. = 1.1 NAIL WITHDRAWAL Allowable Uplift Force Per Nail P allw = 98.4lbf Applied Uplift Force Per Nail P u = 76lbf Confidence Factor: C.F. = 1.3 PAGE 121 109 B8. Connections (truss-to-bond beam, back trussed porch, front entry): New design check conducted. See Tables B-1 through B-3 for all calculated Confidence Factors. LEFT ELEVATION: Confidence Factor: C.F. = 1.5 RIGHT ELEVATION: Confidence Factor: C.F. = 2.9 GARAGE SIDEWALL: Confidence Factor: C.F. = 1.5 FRONT ELEVATION: Confidence Factor: C.F. = 1.2 BACK ELEVATION: Confidence Factor: C.F. = 1.1 BACK TRUSSED PORCH: Confidence Factor: C.F. = 1.3 FRONT ENTRY: Confidence Factor: C.F. = 3.6 Table B-1. Confidence factors for the truss-to-bond beam anchors. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss ( lb ) Anchor IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionLeft ElevationT2GE281101USP/TA1815205.4OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT21002101USP/TA1815201.5OKLeft ElevationAT2A1009101USP/TA1815201.5OKLeft ElevationAT2A1009101USP/TA1815201.5OKLeft ElevationAT2A1009101USP/TA1815201.5OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OK PAGE 122 110 Table B-1. Continued. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss (lb)Anchor IDManufacturer Part No.Capacity of Connection (lb)Confidence Factor (C.F.)ConclusionLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationJ8532101USP/TA1815202.9OKLeft ElevationBJ6476101USP/TA1815203.2OKLeft ElevationBJ4395101USP/TA1815203.8OKLeft ElevationBJ2291101USP/TA1815205.2OKCorner of Left and Back Elev.CJ8412101USP/TA1815203.7OKBack ElevationBJ2291102USP/ (2) TA1823758.2OKBack ElevationBJ4395102USP/ (2) TA1823756.0OKBack ElevationBJ6476102USP/ (2) TA1823755.0OKBack ElevationMH81S3409104Simpson/MGT42001.2OKBack ElevationH101S1640102USP/ (2) TA1823751.4OKBack ElevationH121S1675102USP/ (2) TA1823751.4OKBack ElevationH141S1122102USP/ (2) TA1823752.1OKBack ElevationH161S1746102USP/ (2) TA1823751.4OKBack ElevationH181S1098102USP/ (2) TA1823752.2OKBack ElevationSH201S1631102USP/ (2) TA1823751.5OKBack ElevationS11010102USP/ (2) TA1823752.4OKBack ElevationS11010102USP/ (2) TA1823752.4OKBack ElevationS11010102USP/ (2) TA1823752.4OKBack ElevationS11010102USP/ (2) TA1823752.4OKBack ElevationSH201A1023102USP/ (2) TA1823752.3OKBack ElevationSH181SP986102USP/ (2) TA1823752.4OKBack ElevationSH161SP999102USP/ (2) TA1823752.4OKBack ElevationSH141SP1638102USP/ (2) TA1823751.4OKBack ElevationH1211585102USP/ (2) TA1823751.5OKBack ElevationH1011834102USP/ (2) TA1823751.3OKBack ElevationH813811104Simpson/MGT42001.1OKBack ElevationBJ6476102USP/ (2) TA1823755.0OKBack ElevationBJ4395102USP/ (2) TA1823756.0OKBack ElevationBJ2291102USP/ (2) TA1823758.2OKCorner of Back and Right Elev.CJ8412101USP/TA1815203.7OKRight ElevationBJ2291101USP/TA1815205.2OKRight ElevationBJ4395101USP/TA1815203.8OKRight ElevationBJ6476101USP/TA1815203.2OK PAGE 123 111 Table B-1. Continued. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss ( lb ) Anchor IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationJ8532101USP/TA1815202.9OKRight ElevationBJ6476101USP/TA1815203.2OKRight ElevationBJ4395101USP/TA1815203.8OKRight ElevationBJ2291101USP/TA1815205.2OKCorner of Right and Front Elev.CJ8412101USP/TA1815203.7OKFront ElevationBJ2291102USP/ (2) TA1823758.2OKFront ElevationBJ4395102USP/ (2) TA1823756.0OKFront ElevationBJ6476102USP/ (2) TA1823755.0OKFront ElevationH813493104Simpson/MGT42001.2OKFront ElevationH1011834102USP/ (2) TA1823751.3OKFront ElevationH1211537102USP/ (2) TA1823751.5OKFront ElevationSH141SP1568102USP/ (2) TA1823751.5OKFront ElevationSH161SP1043102USP/ (2) TA1823752.3OKFront ElevationSH181SP1029102USP/ (2) TA1823752.3OKFront ElevationSH201A1209102USP/ (2) TA1823752.0OKFront ElevationS11196102USP/ (2) TA1823752.0OKFront ElevationS11196102USP/ (2) TA1823752.0OKFront ElevationS11196102USP/ (2) TA1823752.0OKFront ElevationS11196102USP/ (2) TA1823752.0OK PAGE 124 112 Table B-1. Continued. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss (lb)Anchor IDManufacturer Part No.Capacity of Connection (lb)Confidence Factor (C.F.)ConclusionFront ElevationJG5601022102USP/ (2) TA1823752.3OKGarage Side WallAT21002101USP/TA1815201.5OKGarage Side WallAT31002101USP/TA1815201.5OKGarage Side WallAT41002101USP/TA1815201.5OKGarage Side WallAT51002101USP/TA1815201.5OKGarage Side WallAT61002101USP/TA1815201.5OKGarage Side WallAT71002101USP/TA1815201.5OKGarage Side WallAT81002101USP/TA1815201.5OKGarage Side WallAT91002101USP/TA1815201.5OKGarage Side WallAT101002101USP/TA1815201.5OK Table B-2. Confidence factors for the anchors/connectors of the back trussed porch. A) Truss-to-header connection. B) Header-to-bond beam and column connections. Connection DescriptionTruss IDMaximum Uplift Reaction of Truss (lb)Connection IDManufacturer Part No.Capacity of Connection (lb)Confidence Factor (C.F.)ConclusionTruss-to-headerT19GE629N/AUSP/LSTA1812702.0OKTruss-to-headerT19629605USP/MSTA 2414272.3OKTruss-to-headerT19629603USP/MSTA 2414272.3OKTruss-to-headerT19629603USP/MSTA 2414272.3OKTruss-to-headerT19629603USP/MSTA 2414272.3OKTruss-to-headerT19629603USP/MSTA 2414272.3OKTruss-to-headerT19629603USP/MSTA 2414272.3OKConnection DescriptionGravity Reaction (lb)Uplift Reaction (lb)Manufacturer Part No.Capacity Gravity (lb)Capacity Uplift (lb)C.F.ConclusionHeader-to-bond beam23071839USP/UMH538 520047852.2OKHeader-to-columnNot Critical1839USP/ (2) TA18Not Critical23751.3OKA)B) PAGE 125 113 Table B-3. Confidence factors for the anchors/connectors of the front entry. A) Truss-to-header connection. B) Header-to-column connections. Connection DescriptionTruss IDMaximum Uplift Reaction of Truss (lb)Connection IDManufacturer Part No.Capacity of Connection (lb)Confidence Factor (C.F.)ConclusionTruss-to-headerT3GE320603USP/HC1011403.6OKTruss-to-headerT3320603USP/HC1011403.6OKTruss-to-headerT3320603USP/HC1011403.6OKConnection DescriptionGravity Reaction (lb)Uplift Reaction (lb)Manufacturer Part No.Capacity Gravity (lb)Capacity Uplift (lb)C.F.ConclusionHeader-to-columnNot Critical622USP/ (2) TA18Not Critical23753.8OKB)A) PAGE 126 APPENDIX C EVALUATION SUMMARY OF STRUCTURE NO. 3 CONCRETE HOME A Confidence Factor (C.F.) has been given to each element and is defined as the allowable stress divided by the calculated stress. Any element possessing a C.F. greater than or equal to 1.0 is considered safe and no immediate design improvements are necessary. If a particular element has a C.F. less than 1.0, the calculated stress exceeds the allowable stress and immediate design improvements may be necessary. The C.F. (as defined in this study) is not to be confused with a Factor of Safety (F.S.). A F.S. was already incorporated in the allowable stress of the structural materials and hence included in the calculation of the C.F. The following Sections A1 through A8 summarize the analytical evaluation of the Structure 3 giving the minimum confidence factor for each major element that makes up the Main Wind Force Resisting System (MWFRS) and the Components and Cladding (C&C). 114 PAGE 127 115 C1. Exterior Concrete Walls (Axial & Out-of-Plane Bending): New design check conducted. Figure C-1 shows the P-M diagram for the 1â€™ wall section in the back elevation. The critical combination of applied bending moment and compression axial load is 2158lbf-ft and 283lbf, respectively. 05001000150020002500300035004000450011042104 P-M Diagram Moment (lbf-ft)Load (lbf)PdPloadsMdMloads Figure C-1. Load-moment interaction diagram for 1â€™ section of wall in the back elevation. Confidence Factor 0.11)(tocotooMMMMPP 89.00.11542)6750(1542215827070283.. ftlbfftlbfftlbfftlbflbflbfFC PAGE 128 116 Figure C-2 shows the P-M diagram for the most critical wall section located in the left elevation. The critical combination of applied bending moment and axial load is 315lbf-ft and 202lbf, respectively. 0500100015002000250030003500 5000500011041.510421042.5104 P-M Diagram Moment (lbf-ft)Load (lbf)PdPloadsMdMloads Figure C-2. Load-moment interaction diagram for most critical wall section (per foot of wall) in left elevation. Confidence Factor 0.11)2/(2/tocotooMMMMPP 03.10.1363)3375(36331513535202.. ftlbfftlbfftlbfftlbflbflbfFC PAGE 129 117 C2. Exterior Concrete Walls Shear Walls (Axial & In-Plane Bending): New design check conducted. The shear walls of the project structure are more than sufficient to resist the applied lateral forces. GARAGE SIDEWALLRIGHT ELEVATIONSW 1SW 2SW 4SW 3SW 2SW 1LEFT ELEVATIONBACK BEDROOM SIDEWALLRIGHT ELEVATIONSW 1SW 2SW 3SW 4 Figure C-3. Shear wall locations in the back, right, and left elevations along with the garage back bedroom sidewalls. LEFT ELEVATION: Shear Wall #1 RIGHT ELEVATION: Shear Wall #1 Allowable Stress: F v = 55psi Allowable Stress: F v = 55psi Calculated Stress: f v = 0.08psi Calculated Stress: f v = 0.86psi Confidence Factor: C.F. = 687.5 Confidence Factor: C.F. = 64 LEFT ELEVATION: Shear Wall #2 RIGHT ELEVATION: Shear Wall #2 Allowable Stress: F v = 55psi Allowable Stress: F v = 55psi Calculated Stress: f v = 0.28psi Calculated Stress: f v = 0.82psi Confidence Factor: C.F. = 196.4 Confidence Factor: C.F. = 67 LEFT ELEVATION: Shear Wall #3 BACK BEDROOM SIDEWALL: Allowable Stress: F v = 55psi Allowable Stress: F v = 55psi Calculated Stress: f v = 0.39psi Calculated Stress: f v = 2.19psi Confidence Factor: C.F. = 141 Confidence Factor: C.F. = 25.1 PAGE 130 118 LEFT ELEVATION: Shear Wall #4 GARAGE SIDEWALL: Allowable Stress: F v = 55psi Allowable Stress: F v = 55psi Calculated Stress: f v = 0.52psi Calculated Stress: f v = 2.57psi Confidence Factor: C.F. = 106 Confidence Factor: C.F. = 21.4 BACK ELEVATION: Shear Wall #1 Allowable Stress: F v = 55psi Calculated Stress: f v = 1.38psi Confidence Factor: C.F. = 39.8 BACK ELEVATION: Shear Wall #2 Allowable Stress: F v = 55psi Calculated Stress: f v = 3.75psi Confidence Factor: C.F. = 14.7 BACK ELEVATION: Shear Wall #3 Allowable Stress: F v = 55psi Calculated Stress: f v = 1.75psi Confidence Factor: C.F. = 31.4 BACK ELEVATION: Shear Wall #4 Allowable Stress: F v = 55psi Calculated Stress: f v = 0.50psi Confidence Factor: C.F. = 110 PAGE 131 119 C3. Exterior Concrete Walls â€“ Pier Analysis (Axial & In-Plane Bending): New design check conducted FRONT ELEVATION P 1P 2P 3P 4CB 1CB 2P 1CB 1P 2GARAGE "GOAL POST" Figure C-4. Piers and coupling beams in the front elevation along with the garage â€œgoal postâ€. GARAGE â€œGOAL POSTâ€: Piers #1 and #2 Allowable Moment: M allw = 8160lbf-ft Allowable Shear Stress: F v = 55psi Applied Moment: M = 2235lbf-ft Calculated Shear Stress: f v = 4.6psi Confidence Factor: C.F. = 3.65 Confidence Factor: C.F. = 12 PAGE 132 120 GARAGE â€œGOAL POSTâ€: Figure C-5 shows the P-M diagram for Coupling Beam #1). The maximum combination of applied bending moment and tensile axial load is 1655lbf-ft and 2115lbf, respectively. 01000200030004000500060007000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdTMdM Figure C-5. Tensile load-moment interaction diagram for coupling beam 1. 0.1aoMMTP 425.065031655124002115 ftlbfftlbflbflbf Confidence Factor 35.2425.01..FC Allowable Shear Stress: F v = 55psi Calculated Shear Stress: f v = 7.1psi Confidence Factor: C.F. = 7.7 PAGE 133 121 FRONT ELEVATION: Figure C-6 shows the P-M diagram for Pier #1. The applied maximum combination of bending moment and tensile axial load is 3295lbf-ft and 5170lbf, respectively. 0200040006000800011041.21041.4104 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd1P1'Md1M1' . Figure C-6. Tensile load-moment interaction diagram for pier 1 of the front elevation 0.1aoMMTP 68.0125193295124005170 ftlbfftlbflbflbf Confidence Factor 47.168.01..FC Allowable Shear Stress: F v = 55psi Calculated Shear Stress: f v = 5.8psi Confidence Factor: C.F. = 9.5 PAGE 134 122 FRONT ELEVATION: Figure C-7 shows the P-M diagram for Pier #2. The applied maximum combination of bending moment and tensile axial load is 11454lbf-ft and 352lbf, respectively. 0500011041.510421042.51043104 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd2P2'Md2M2' . Figure C-7. Tensile load-moment interaction diagram for pier 2 of the front elevation. 0.1aoMMTP 44.0275981145412400352ftlbfftlbflbflbf Confidence Factor 27.244.01..FC Allowable Shear Stress: F v = 55psi Calculated Shear Stress: f v = 2.3psi Confidence Factor: C.F. = 24 PAGE 135 123 FRONT ELEVATION: Figure C-8 shows the P-M diagram for Pier #3. The applied maximum combination of bending moment and tensile axial load is 7650lbf-ft and 4280lbf, respectively. 0500011041.510421042.510431043.5104 2104 1.5104 1104 50000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTd3P3'Md3M3' . Figure C-8. Tensile load-moment interaction diagram for pier 3 of the front elevation. 0.1aoMMTP 48.0306297650186004280 ftlbfftlbflbflbf Confidence Factor 1.248.01..FC Allowable Shear Stress: F v = 55psi Calculated Shear Stress: f v = 4.9psi Confidence Factor: C.F. = 11.2 FRONT ELEVATION: Pier # 4 Allowable Moment: M allw = 19737lbf-ft Allowable Shear Stress: F v = 55psi Applied Moment: M = 1929lbf-ft Calculated Shear Stress: f v = 0.5psi Confidence Factor: C.F. = 10.2 Confidence Factor: C.F. = 110 PAGE 136 124 FRONT ELEVATION: Figure C-9 shows the P-M diagram for Coupling Beams #1 and #2. The maximum combination of applied bending moment and tensile axial load is 1278lbf-ft and 811lbf, respectively. 01000200030004000500060007000 1.4104 1.2104 1104 8000 6000 4000 20000 Load Moment Interaction DiagramMoment lbf-ftAxial Load lbfTdTMdM Figure C-9. Tensile load-moment (negative) interaction diagram for Coupling Beams 1 and 2. 0.1aoMMTP 26.06503127812400811 ftlbfftlbflbflbf Confidence Factor 84.326.01..FC Allowable Shear Stress: F v = 55psi Calculated Shear Stress: f v = 4.2psi Confidence Factor: C.F. = 13.1 PAGE 137 125 C4. Coupling Beams (Gravity Loads): New design check conducted Figure C-10. Location of critical coupling beams in the project structure. Allowable Moment M allw = 6305lbf-ft Max. Applied Moment M = 4558lbf-ft Confidence Factor: C.F. = 1.4 Allowable Shear Stress F v = 55psi Max. Calculated Shear Stress f v = 46psi Confidence Factor: C.F. = 1.2 PAGE 138 126 C5. Back Trussed Porch / Interior Load Bearing Wall: New design check conducted INTERIOR LOAD BEARING WALLS BACK TRUSSED PORCH Figure C-11. Location of the back trussed porch and interior load bearing wall. BACK TRUSSED PORCH: The Confidence Factors for the timber headers and 4x4 post that frame the back porch are as follows: 2 2x12 HEADERS â€“ DOWNWARD FORCES 2 2x12 HEADERS â€“ UPLIFT FORCES Allowable Bending Stress F b = 1219psi Allowable Bending Stress F b = 1560psi Calculated Bending Stress b = 821psi Calculated Bending Stress b = 1234psi Confidence Factor: C.F. = 1.5 Confidence Factor: C.F. = 1.26 2 â€“ 2x12 HEADERS Allowable Shear Stress F v = 144psi Calculated Shear Stress f v = 88psi Confidence Factor: C.F. = 1.64 4x4 POSTS â€“ DOWNWARD FORCES Allowable Compressive Axial Load P allw = 582lbf Applied Compressive Axial Load P = 184lbf Confidence Factor: C.F. = 3.16 PAGE 139 127 4x4 POSTS â€“ UPLIFT FORCES Allowable Tensile Axial Load P allw = 1063lbf Applied Tensile Axial Load P = 241lbf Confidence Factor: C.F. = 4.4 INTERIOR LOAD BEARING WALL: DOUBLE TOP PLATE â€“ DOWNWARD FORCES Allowable Bending Stress F b = 2063psi Allowable Shear Stress F v = 113psi Calculated Bending Stress b = 1454psi Calculated Shear Stress f v = 228psi Confidence Factor: C.F. = 1.42 Confidence Factor: C.F. = 0.49 DOUBLE TOP PLATE â€“ UPLIFT FORCES Allowable Bending Stress F b = 2640psi Allowable Shear Stress Fv = 144psi Calculated Bending Stress b = 1358psi Calculated Shear Stress fv = 213psi Confidence Factor: C.F. = 1.94 Confidence Factor: C.F. = 0.68 2x4 VERTICAL STUD â€“ DOWNWARD FORCES Allowable Axial Compressive Stress F b = 515psi Calculated Axial Compressive Stress b = 682psi Confidence Factor: C.F. = 0.76 2x4 VERTICAL STUD â€“ UPLIFT FORCES Allowable Axial Tensile Stress F b = 1063psi Calculated Axial Tensile Stress b = 719psi Confidence Factor: C.F. = 1.48 J-BOLT CONNECTIONS Allowable Connection Load (based on crushing stress of wood) P allw = 996lbf Applied Connection Load (maximum of two design checks) P = 1576lbf Confidence Factor: C.F. = 0.63 PAGE 140 128 C6. Doors and Window Anchorage/Roof Sheathing: Door/Sliding Glass Door, Window, and Garage Door Anchorage: WINDOW ANCHORAGE â€“ TapCon CONNECTION Allowable Shear Load V allw = 255lbf Applied Shear Load V = 213lbf Confidence Factor: C.F. = 1.2 DOOR/SLIDING GLASS DOOR ANCHORAGE â€“ TapCon CONNECTION Allowable Shear Load V allw = 255lbf Applied Shear Load V = 242lbf Confidence Factor: C.F. = 1.0 GARAGE DOOR ANCHORAGE â€“ J-BOLT CONNECTION Allowable Connection Load (based on crushing stress of wood) P allw = 996lbf Applied Connection Load P = 694lbf Confidence Factor: C.F. = 1.4 Roof Sheathing: Due to the applied wind pressure, the sheathing was checked for bending, shear, and deflection. SHEATHING Allowable Wind Pressure (with allowable stresses for bending and shear) p allw = 117psf Applied Design Wind Pressure p w = 106 Confidence Factor: C.F. = 1.1 NAIL WITHDRAWAL Allowable Uplift Force Per Nail P allw = 98.4lbf Applied Uplift Force Per Nail P u = 76lbf Confidence Factor: C.F. = 1.3 PAGE 141 129 C7. Connections (truss-to-bond beam, back trussed porch, front entry): New design check conducted. See Tables C-1 through C-2 for all calculated Confidence Factors. LEFT ELEVATION: Confidence Factor: C.F. = 0.9 BACK ELEVATION: Confidence Factor: C.F. = 0.7 BACK BEDROOM SIDEWALL: Confidence Factor: C.F. = 0.7 RIGHT ELEVATION: Confidence Factor: C.F. = 2.3 FRONT ELEVATION: Confidence Factor: C.F. = 0.6 GARAGE SIDEWALL: Confidence Factor: C.F. = 0.8 BACK TRUSSED PORCH: Confidence Factor: C.F. = 0.6 Table C-1. Confidence factors for the truss-to-bond beam anchors. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss ( lb ) Anchor IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionLeft ElevationCJ6292101USP/TA1811694.0OKLeft ElevationBJ2282101USP/TA1811694.1OKLeft ElevationBJ4372101USP/TA1811693.1OKLeft ElevationH621250101USP/TA1811690.9Left ElevationH82958101USP/TA1811691.2OKLeft ElevationT2766101USP/TA1811691.5OKLeft ElevationT2766101USP/TA1811691.5OKLeft ElevationT2766101USP/TA1811691.5OKLeft ElevationT2766101USP/TA1811691.5OKLeft ElevationT2766101USP/TA1811691.5OKLeft ElevationT2766101USP/TA1811691.5OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OK FAILS PAGE 142 130 Table C-1. Continued. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss (lb)Anchor IDManufacturer Part No.Capacity of Connection (lb)Confidence Factor (C.F.)ConclusionLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationJ8503101USP/TA1811692.3OKLeft ElevationBJ6449101USP/TA1811692.6OKLeft ElevationBJ4372101USP/TA1811693.1OKLeft ElevationBJ2282101USP/TA1811694.1OKCorner of Left and Back Elev.CJ8389101USP/TA1811693.0OKBack ElevationBJ2282101USP/TA1811694.1OKBack ElevationBJ4372101USP/TA1811693.1OKBack ElevationBJ6449101USP/TA1811692.6OKBack ElevationMH813573102USP/ (2) TA1823380.7Back ElevationMH1011630101USP/TA1811690.7Back ElevationMH1211645101USP/TA1811690.7Back ElevationH141A1114101USP/TA1811691.0OKBack ElevationH161A1698101USP/TA1811690.7Back ElevationH181A1095101USP/TA1811691.1OKBack Bedroom Side WallMH43960102USP/ (2) TA1823382.4OKBack Bedroom Side WallMH631681101USP/TA1811690.7Back Bedroom Side WallMH831713101USP/TA1811690.7Back ElevationH2011026101USP/TA1811691.1OKBack ElevationT11013101USP/TA1811691.2OKBack ElevationT11013101USP/TA1811691.2OKBack ElevationT11013101USP/TA1811691.2OKBack ElevationT11013101USP/TA1811691.2OKBack ElevationH2011026101USP/TA1811691.1OKBack ElevationH1811040101USP/TA1811691.1OKBack ElevationH161987101USP/TA1811691.2OKBack ElevationH1411000101USP/TA1811691.2OKBack ElevationH1211695101USP/TA1811690.7Back ElevationH1011829101USP/TA1811690.6Back ElevationH813947102USP/ (2) TA1823380.6Back ElevationBJ6449101USP/TA1811692.6OKBack ElevationBJ4372101USP/TA1811693.1OKBack ElevationBJ2282101USP/TA1811694.1OKCorner of Back and Right Elev.CJ8389101USP/TA1811693.0OKRight ElevationBJ2282101USP/TA1811694.1OKRight ElevationBJ4372101USP/TA1811693.1OKRight ElevationBJ6449101USP/TA1811692.6OKRight ElevationJ8503101USP/TA1811692.3OK FAILSFAILSFAILSFAILSFAILSFAILSFAILSFAILSFAILS PAGE 143 131 Table C-1. Continued. Truss Connection LocationTruss IDMaximum Uplift Reaction of Truss ( lb ) Anchor IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationJ8503101USP/TA1811692.3OKRight ElevationBJ6449101USP/TA1811692.6OKRight ElevationBJ4372101USP/TA1811693.1OKRight ElevationBJ2282101USP/TA1811694.1OK C orner o f Ri g h t an d F r o n t El e v . CJ8389101USP/TA1811693.0OKFront ElevationBJ2282101USP/TA1811694.1OKFront ElevationBJ4372101USP/TA1811693.1OKFront ElevationBJ6449101USP/TA1811692.6OKFront ElevationH813624102USP/ (2) TA1823380.6Front ElevationH1011829101USP/TA1811690.6Front ElevationH1211695101USP/TA1811690.7Front ElevationH1411011101USP/TA1811691.2OKFront ElevationH161996101USP/TA1811691.2OKFront ElevationH1811040101USP/TA1811691.1OKFront ElevationH2011200101USP/TA1811690.97Front ElevationT11187101USP/TA1811690.98 FAILSFAILSFAILSFAILSFAILS PAGE 144 132 Table C-2. Confidence factors for the anchors/connectors of the back trussed porch. A) Truss-to-header connections. B) Header-to-bond beam and column connections. Connection DescriptionTruss IDMaximum Uplift Reaction of Truss ( lb ) Connection IDManufacturer Part No.Capacity of Connection ( lb ) Confidence Factor ( C.F. ) ConclusionTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerJ4363603HUGHES HC1012103.3OKTruss-to-headerBJ2282603HUGHES HC1012104.3OKTruss-to-headerCJ4250603HUGHES HC1012104.8OKTruss-to-headerBJ2282603HUGHES HC1012104.3OKTruss-to-headerMH431057605HUGHES RT2411214321.4OKTruss-to-headerMH631875603HUGHES HC1012100.6FAILSTruss-to-headerMH831881603HUGHES HC1012100.6FAILSConnection Descri p tionGravity ReactiUplift Reaction ( lb ) Manufacturer Part No.Capacity Gravit y Capacity U p lift C.F.ConclusionHeader-to-bond beam19443850NFM 35x12U583334820.9FAILSHeader-to-columnNot Critical2955USP/ (2) TA18Not Critical28640.97FAILSA)B) PAGE 145 APPENDIX D ANALYSIS OF RECOMMENDED BOND BEAM National Quality Demonstration Project Spring 2003Recommended Bond Beam Design Check_____________________________________________________________________________Bond Beam Analysis: The bond beam must carry all of the wind uplift forces and transfer the load to the existing vertical steel in the walls. Cracking of the mortar joint will occur.Location: top 2 courses of wall Bond Beam size: 16 inchReinforcement: one No. 5 reinforcing bar placed at top and bottomFigures of Typical Double Course Bond Beam and Section Properties 133 PAGE 146 134 Em1350ksimodulus of elasticity of masonrycc2.0inclear coverdb0.625indiameter of barFbfm'3 Fb500psinet allowable cpmressive stress due to bending onlyFs20000psiGrade 40allowable tensile and compressive stress of steelAs4 db2fy40ksiyield strength of grade 40 steelnEsEm n21.48modular ratioTypical 16" (double course) bond beam. See Visual Analysis 3.5 model for spacing of reinforcing bars in project structure. Note: Flexural reinforcement within the bond beam is not shown.Typical Bond Beam Section ______________________________________________________________________________Section PropertiesDefine Unitsksi1000psikip1000lbfSection Properties Allowable Stresses h16inheight of beamfm'1500psicompressive strength masonryb7.625inwidth of beamEs29000ksimodulus of elasticity of steelEm900fm' PAGE 147 135 Analysis of Bond BeamAnalyze all sections of the bond beam in the structure to determine the maximum negative bending moment, positive bending moment, and shear using the truss reactions provided in the Space Coast Truss Inc. Truss Engineering Specifications Package (Structure 2) and Visual Analysis 3.5.The following were taken from the results of the Visual Analysis 3.5 models. See attached. Use the above maximum moments and shear force and determine if the bond beam is adequate. Moment: Shear: Mpos2797lbfft Vmax3946lbf Mneg2084lbfft Support Reaction: Rmax5612lbf PAGE 148 136 SUMMARY: As shown above, the actual stresses in the masonry and steel due to the positive and negative bending moment does not exceed the stresses that are allowed according to the MSJC. Therefore, for the given spacing of the grouted cells within the walls of the structure, a double course (16") bond beam is adequate. _________________________________________________________________________ s9162psi snIt Mposddb2 kd m175psi mMposkdIt Calculated stresses in masonry and steel _ ____________________________________________________________________________ _ It780.9in4Itbkd312 bkdkd2 2Astdkd()2 _ ____________________________________________________________________________ _ kd4.076inkdFindkdikdi22 bAstdAstkdi0 Giveninitial guesskdi2inequation solvertransformed sectionAstnAsd13.7indhccdb2 Determine neutral axis POSITIVE and NEGATIVE BENDING MOMENTDetermine the Flexural Capacity of the Bond Beam PAGE 149 137 conclusion"vertical reinforcement is adequate" conclusion"vertical reinforcement is adequate"TsRmaxif"increase bar size"otherwise Ts6136lbf TsFsAscapacity of vertical steel barsgrade 40 steelFs20000psiAllowable tensile stress in steelmaximum reaction that must be carried by vertical # 5 bar.Rmax5612lbfDetermine if the Vertical Reinforcement is Adequate to Carry the Applied Loads. _ ____________________________________________________________________________ _ SUMMARY: The allowable shear strength of the bond beam is adequate. Conclusion"No Shear Reinforcing Required" Conclusion"Shear Reinforcing Required"fvminFv50psiif"No Shear Reinforcing Required"otherwise allowable shear stressFv38.73psiFvfm'psi ACI 530: states where reinforcement is not provided to resist all of the calculated shear, fv shall not exceed Fv or 50psifv37.81psifvVmaxbd d13.688indhccdb2 shear stress in masonry:Vmax3946lbfDetermine the Shear Capacity of the Bond Beam PAGE 150 138 conclusion"anchorage is adequate" Ta6136lbfconclusion"anchorage is adequate"TaRmaxif"anchorage fails"otherwise TaFsAsCapacity of Anchorage: Vertical reinforcement is fully developed Typical detail of 90 deg standard hook w/ No. 5 bar_____________________________________________________________________________ 5db3.125inNo. 5 bar shall have a minimum diameter bend of 5dble7.03inld18.75inequivalent development length developed by the standard hook: Fs = 7500 psile11.25dbrequired embedment lengthfor full developmentld0.0015dbFs1psi length of extension to free end12db7.5inallowable stress for steelFs20000psiRmax5612lbfdiameter # 5 bardb0.625inmaximum reaction in vertical reinforcementStandard Hook: A 90 degree turn plus extension of at least 12 bar diameters at free end of bar.Grade 40 bar minimum diameter of 5 bar diametersDetermine if the Anchorage of the Vertical Reinforcement to the Bond Beam is Adequate. PAGE 151 LIST OF REFERENCES American Concrete Institute (ACI). (1999). â€œBuilding code requirement for structural concrete (318-99) and commentary (318R-99).â€ ACI, Farmington Hills, MI. American Forest & Paper Association (AF&PA). (1997). â€œNational design specification for wood construction (NDS-97).â€ AF&PA/AWC, Washington, DC. American Society of Civil Engineers (ASCE). (1998). â€œMinimum design loads for buildings and other structures (ASCE 7-98).â€ ASCE, Reston, VA. Anderson, L.O., and Smith, W.R. (1965) â€œHouses can resist hurricanes FPL 33â€ U.S. Forest Service Department of Agriculture (USDA), Washington, DC. Carter, L.E., and Nichols, G.G. (1994) â€œAre building codes and/or enforcement adequate for hurricane protection.â€ Hurricanes of 1992, ASCE , New York, 626-631. Cope, A., Gurley, K., Pinelli, J., Hamid, S. (2003). â€œA simulation model for wind damage predictions in Florida.â€ 11th International Conference on Wind Engineering, Lubbock Texas, June 2-5. 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(1988). â€œGuide to the use of the wind load provisionsANSI A58.1.â€ Institute for Disaster Research, Texas Tech University TX. ery, P.J., Twisdale, L.A., and Young, M.A. (2002) â€œMitigation of hurric V in residential construction through the residential construction mitigation program.â€ Solutions to Coastal Disasters , ASCE, Reston, VA, 997-1012. Zollo, R.F. (1993). â€œHurricane Andrew, August 24, 1992, Structural performance obuildings in Dade County, Florida.â€ Dept. of Civil and Architectural EngineeUniv. of Miami, Coral Gables, FL. PAGE 154 BIOGRAPHICAL SKETCH earlyfrom f Science in Ciin e Dnd Coastal Engineering. He plans to receive his Master of of the meivil Engineering Honor hig buildings and other structures. The author was born on February 19, 1978, in New Brunswick, New Jersey. In his childhood, he lived in Alabama and later moved to Stuart, Florida. After graduating high school, he enrolled at the University of Central Florida, Orlando, FL, in the fall of 1996. In May of 2001, the author graduated from UCF earning a Bachelor ovil Engineering. In the fall of 2001, the author began working towards earning a masterâ€™s degree in structural engineering at the University of Florida, Gainesville, FL epartment of Civil a th Engineering degree in May 2003, with a concentration in structural engineering. Throughout his undergraduate and graduate career the author was a member rican Society of Civil Engineers, Chi Epsilon National C A Society, the American Concrete Institute, and Sigma Phi Epsilon Fraternity. After graduation in May 2003, the author plans to relocate to Chicago, Illinois, where he will start a new career with Halvorson Kaye Structural Engineers designing low h-rise to 142 |