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The Homebuilders' Guide to Earthquake-Resistant Design and Construction (FEMA 232) presents seismic design and construction guidance for one- and two- family houses in a manner that can be utilized by homebuilders, knowledgeable homeowners, and other non-engineers. The manual includes prescriptive building detail plans based on the state-of-the-art earthquake-resistant design for use by homebuilders and others in the construction of a non-engineered residential structure. Further, the manual also uses the results of recent loss investigations as well as current research and analysis results to identify a number of specific above-code measures for improved earthquake performance along with their associated costs.
A typical modern house is used to illustrate the application and benefits of above-code measures.
This manual replaces the Home Builders Guide to Seismic Resistant Construction (FEMA 232) published by FEMA in 1998.
From the Preface
The Federal Emergency Management Agency (FEMA), which is part of the Department of Homeland Security, works to reduce the ever-increasing cost that disasters inflict on the nation. Preventing losses before they occur by designing and constructing buildings and their components to withstand anticipated forces from various hazards is one of the key components of mitigation and is one of the most effective ways of reducing the cost of future disasters.
The National Earthquake Hazards Reduction Program (NEHRP) is the federal program established to address the nation's earthquake threat. NEHRP seeks to resolve two basic issues: how will earthquakes affect us and how do we best apply our resources to reduce their impact on our nation. The program was established by Congress under the Earthquake Hazards Reduction Act of 1977 (Public Law 95-124) and was the result of years of examination of the earthquake hazard and possible mitigation measures. Under the NEHRP, FEMA is responsible for supporting program implementation activities, including the development, publication, and dissemination of technical design and construction guidance documents.
Generally, there has not been much technical guidance addressing residential buildings unless they are located in areas of high seismicity or exceed a certain size of height. This is because most residential buildings were thought to perform fairly well in earthquakes due to their low mass and simple construction. While buildings may not normally experience catastrophic collapse, they can still suffer significant amounts of damage, rendering them uninhabitable. This is especially true when construction techniques are less than adequate. What is particularly important from FEMA's point of view is that, given the sheer number of this type of building, even minor damage represents a significant loss potential and temporary housing demand that would need to be addressed after an earthquake by all levels of government.
After the San Francisco earthquake in 1971, a study of residential buildings and the damage they suffered was conducted by a team of experts under funding from the Department of Housing and Urban Development (HUD) and the National Science Foundation (NSF). HUD utilized these data to develop a non-engineering document entitled Home Builder's Guide to Earthquake Design. This manual, originally published in 1980, provided easy-to-follow information to the average homebuilder on steps for reducing potential earthquake damage. In July 1992 it was reprinted as a joint FE
Since that time, there have been several significant changes that needed to be incorporated into this document to keep it current. The first and most important change was the completion of the FEMA-funded Consortium of Universities for Research in Earthquake Engineering (CUREE) - Caltech Woodframe Project. This project was funded using FEMA Hazard Mitigation Grant Program funds available after the Northridge earthquake and was designed to address the unexpected amount of damage suffered by wood frame residential structures. Similar to the successful FEMA/SAC Steel Moment Frame Buildings Project, this effort combined academic research and testing of wood frame buildings and components with the development of engineering-based design guidance for future construction. The project yielded some interesting findings that needed to be captured in a guidance document.
A second change was the development and publication of the 2000 International Residential Code (IRC) by the International Code Council. This model residential building code replaced the Council of American Building Officials (CABO) One-and Two-Family Dwelling Code, which did not adequately address earthquake loads. The IRC reflects the NEHRP Recommended Provisions and is intended to adequately address the earthquake hazard.
This publication presents seismic design and construction guidance for one- and two-family houses in a manner that can be utilized by homebuilders, knowledgeable homeowners, and other non-engineers. It incorporates and references the prescriptive provisions of the 2003 International Residential Code as well as the results of the FEMA-funded CUREE-Caltech Woodframe Project. The manual includes prescriptive building detail plans based on state-of-the-art earthquake-resistant design for use by homebuilders and others in the construction of a non-engineered residential structure. Further, the manual also uses the results of recent loss investigations as well as current research and analysis results to identify a number of specific above-code measures for improved earthquake performance along with their associated costs. A typical modern house is used to illustrate the application and benefits of above-code measures. This manual replaces the Home Builders Guide to Seismic Resistant Construction (FEMA 232) published by FEMA in August 1998 as well as earlier FEMA and HUD versions.
Contents
Preface. Acknowledgements. Executive Summary. Chapter 1: Introduction. Chapter 2: Earthquake-Resistance Requirements. Chapter 3: Foundations and Foundation Walls. Chapter 4: Floor Construction. Chapter 5: Walls. Chapter 6: Roof-Ceiling Systems. Chapter 7: Chimneys, Fireplaces, Balconies, and Decks. Chapter 8: Anchorage of Home Contents. Chapter 9: Existing Houses. Appendix A: Analysis of Model House Used in this Guide. Appendix B: Earthquake Provisions Checklist for Builders and Designers. Appendix C: Earthquake Provisions Checklist for Designers and Plan Checkers. Appendix D: Significant Changes for the 2006 International Residential Code. Appendix E: References and Additional Resources. Appendix F: Homebuilder's Guide Project Participants. |
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