|CUREE-Caltech Woodframe Project
Element 5 - Education & Outreach
Project Manager: Jill Andrews - Caltech (formerly with SCEC)
One of the keys to mitigation is to educate owners and residents so that they initiate actions to reduce the risks to life and property posed by hazardous types of existing wood buildings. Specific targets here include older houses on cripple-wall foundations and multi-story apartment or condominium buildings with "tuck-under" parking. For new construction, engineers must be taught the techniques that will be forthcoming from the Building Codes and Standards Element's efforts, and contractors must be instructed in the basics of the components of lateral load resisting systems and why each component is important. Vehicles to meet these goals will include comprehensive eye-catching publications that hold the reader's attention, traveling exhibits at home-care shows and county fairs, and seminars accompanied by carefully prepared notes and videos. Resolution of discrepancies among the messages being given to the public will be a key objective. For example, a common perception is that if one merely retrofits a house with anchor bolts, it follows that it will then have above average seismic performance (e.g., just a few easily repairable cracks after experiencing a severe earthquake), that more extensive measures or diagnoses are not necessary, and that it may not be worth it to purchase insurance. These quick conclusions, or misconceptions, are in conflict with both expert engineering opinion and the Northridge data.
An important part of this effort to mitigate the risk to life and property posed by woodframe buildings is to communicate the problems and their solutions to owners, contractors, engineers, architects, building officials and other persons with concerns in this area. Development of the educational products will be coordinated by the Southern California Earthquake Center, and a wide variety of people who will use the results ("users," "end users," "implementation community") will be involved. Note that separate-but-related products of the Education and Outreach Element are aimed at specific markets or audiences, based on the assumption that the type of information and the way it is presented must be different for people of different backgrounds and needs. For example, structural engineers can understand and must use analytical methods in their work, whereas contractors do not engage in structural analysis but are central to the quality control of the as-built structure. Architects belong to different organizations and read different periodicals than engineers, and so on, and the project will attempt to look at the world through each audience's eyes to devise education and outreach efforts that are effective. At a minimum, the following are key audiences: owners; building inspectors; contractors and construction industry workers; architects; engineers. ("Building inspectors" here refers to state or local government building department employees; in addition, there is a large private consulting field providing pre-purchase house inspection services, for seismic as well as the many non-seismic characteristics of a building, which is another important audience). The project also will organize its informational activities according to the type of building, because there is a major difference between houses as compared to multi-unit residential buildings, both in terms of audience and in the technical aspects involved.
Various materials for educating homeowners on why and how to retrofit their woodframe houses already exist. Notable is the information being prepared by the City of San Leandro, which includes seminar materials, and various packages of information disseminated by California OES over the past 15 years. The text Peace of Mind in Earthquake Country by Peter Yanev, and the recently revised HUD Homebuilders Guide also deal with the subject. However, in spite of these and other sources of information, homeowners are still not undertaking seismic retrofits of their homes in adequate numbers. So, as part of this project, a review of existing educational materials will be made from the perspective of motivating home owners to take effective action, and various products will be designed to meet this need.
One option is to devote project resources to the revision of others' existing educational materials or training programs via subcontracts. For example, the Association of Bay Area Governments (ABAG) has successfully run a training course on Earthquake Retrofit of Wood-Frame Houses.
One possible project will be a portable traveling exhibit that can be set up at home products conventions and county fairs. Included in the exhibit will be lengths of cripple walls, braced and unbraced, with sills (bolted and unbolted) and simulated foundations.
Results pertinent to house retrofitting developed in the Testing and Analysis and Field Investigations Elements will be used to prepare a new retrofit guide on hillside houses, a topic that is currently treated inadequately or not at all.
The new chapter 92 of the City of Los Angeles Building Code contains retrofit provisions for cripple walls that would be understandable to many homeowners. It will be useful as a guide to the owner who has already decided to retrofit. What is envisaged here is a more complete document that presents the benefits of retrofit and thereby convinces homeowners to act. Photos would be included from the Coalinga, Whittier, Loma Prieta and Northridge Earthquakes of houses that suffered collapse of their cripple walls. Cases would be presented of retrofitted houses that performed well, contrasted with unretrofitted houses nearby whose cripple walls failed. Other sections of the document, all professionally illustrated, would include an elementary treatment of the seismic hazard with estimates of the potential for strong shaking in various areas, the basics of sill-plate bolting and cripple-wall bracing, how to adapt to a variety of geometric and foundation conditions, choices of materials and hardware, cost estimates for a range of retrofit solutions, a do-it-yourself guide, and how to choose a contractor. In addition, nonstructural items such as chimneys, water heaters and gas valves would be covered. Another section would be devoted to special problems of hillside houses.
Retrofit of Multi-Story Residences
There are approximately 20,000 multi-story wood apartment or condominium buildings in the Los Angeles area containing "tuck-under" parking in the first story that could suffer partial collapse in this first story in a strong earthquake. The Northridge Meadows Apartments where 16 people died is one of many examples of such collapses that occurred during the Northridge Earthquake. The Testing and Analysis and the Field Investigation Elements of this project address retrofits of soft-story wood buildings, and results of this work, along with all other relevant information, will be source material for two documents, one directed at building owners and residents, and the other at engineers carrying out retrofit designs.
The document for building owners and residents would be similar in purpose and scope to the one described above targeting home owners, i.e., it would have a clear description of the hazard and how to abate it. There would be an additional section which spells out the legal responsibilities of owners and the rights of residents as well as actions that residents who are concerned about their building could take to bring about an engineering assessment and possible subsequent retrofit. Case studies of multi-residential buildings damaged in the Loma Prieta and Northridge earthquakes, including repair and legal actions, will be included.
For practicing engineers, appropriate retrofit design examples for typical conditions found in the field will either be included in the Engineering Procedures document (3.3) or a separate report for this Element.
Wood Engineering Seminars
Engineers typically do not apply ductile design concepts in a rational way to wood structures. Developing such information is a goal of the structural testing and field investigation of the wood project. It is anticipated that ductile design procedures are going to progress rapidly as a result of the Testing and Analysis and Field Investigations Elements, reflected in building codes and standards. In order to transfer this knowledge to the engineering design community, code writers, and building officials, seminars will be held. A major feature of the seminars will be a carefully prepared set of design examples covering a wide range of structures, both new construction and retrofit. A unique feature of the presentations will be edited videos of structural testing to show firsthand what works and what does not, and what types of damage occur for various combinations of shaking intensity and design force level. Quality control for seismic safety will also be addressed with emphasis.
Similar seminars will be conducted for architects and architectural educators. The focus of these seminars will be on simplified methods and intuitive interpretations of the new ductile design procedures, as well as approximate design methods appropriate for architects in a typical structures curriculum in schools of architecture. Seismic seminars for architectural educators are currently being conducted by the American Institute of Architects. These seminars could be further developed, including new and emerging seismic design methods resulting from this study. An example is computerized teaching and design tools, such as the software "LDG" developed by Prof. Schierle, Associate Project Manager for Field Investigations, that has been used to allow university architecture and engineering students to explore various seismic design alternatives that are difficult to compare by laborious hand calculations. ("Computer Aided Design for Wind and Seismic Forces," Computer Supported Design in Architecture, Association for Computer Aided Design in Architecture, 1992) Visual aids, such as the edited testing videos, and quality control issues will also be introduced.
SEAOSD (Structural Engineers Association of San Diego) has recently produced a seismic detailing manual, containing standard terminology and details, that should be complemented by the proposed seminars: Information from our project may imply revisions to future editions of the SEAOSD booklet, and that publication may be a useful text in the engineering seminars.
Poor quality of construction was a major contributor to the damage in the Northridge Earthquake, accounting for up to a third of the total damage cost according to some estimates. To address this problem, there have been efforts to bring about more inspection at the job site and to involve the design engineer in these inspections. While this can have much positive benefit, it would also be desirable to develop an educational program aimed at contractors because it is believed that if the contractor understands better the role and importance of the components of the lateral load resisting system, better construction quality will result. This project will include a seminar series and an accompanying document that deals with the structural system in an understandable way.
Examples of poor construction and their consequences from the Northridge earthquake, including damage caused and subsequent claims and legal actions, will be included. The seminar series will be designed to be of benefit to inspectors as well as contractors.
Element 5 Report: January 2001
Education Modules: Timber Web Modules