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This webinar was co-sponsored by ASCE's Structural Engineering Institute (SEI) and ASCE Continuing Education
Instructor: John Lawson, C.E., S.E., M.ASCE
Course Length: 1 Hour
Purpose and Background
Buildings with large wood diaphragms supporting heavy concrete or masonry walls are very common in seismically active portions of the United States. The current seismic design approach is based on the equivalent lateral force (ELF) method whose underlying assumptions significantly differ from the actual dynamic response of these buildings. The seismic behavior of rigid wall-flexible roof diaphragm (RWFD) buildings is dominated by the wood diaphragm's response instead of the walls' in-plane response. Furthermore, the diaphragm's ductility and overstrength capacity is unique to its own construction. Yet the current design methodology employed by practitioners directly ties the wood diaphragm shears and overstrength to the characteristics of the seismic force-resisting system's (SFRS) concrete or masonry vertical elements. This webinar evaluates the shortcomings of past practices in both the seismic design of the main diaphragm as well as the out-of-plane anchorage of the perimeter heavy walls to the diaphragm. It also discusses a proposal for a new design methodology, providing a rational approach to improving performance in these wood diaphragms.
Primary Discussion Topics
- Past performance issues
- Origins of current building code provisions
- Actual diaphragm and building behavior
- Ideas to improve performance
- Implications for future building code provisions
Learning Outcomes
Upon completion of this course, you will be able to:
- Recognize the historical seismic performance problems of this building type
- Become familiar with the origins of anchoring heavy walls to wood diaphragms
- Decide how to apply the various code provisions to diaphragm and wall anchorage design
- Determine the limitations of current diaphragm design practices
- Identify a new approach to increase diaphragm performance
Webinar Benefits
- Gain an appreciation for the origins of current code provisions
- Find out the latest understanding in wood diaphragm seismic behavior
- Get a glimpse of the possible direction of the seismic code provisions
- Obtain a variety of tools to evaluate the seismic performance of wood diaphragms
Assessment of Learning Outcomes
Students' achievement of the learning outcomes will be assessed via a short post-assessment (true-false, multiple choice and fill in the blank questions).
Intended Audience
- Structural engineers
- Civil engineers
- Building officials
- Building code developers
- Seismic hazard mitigation specialists
Webinar Outline
- Characteristics of Rigid Wall - Flexible Diaphragm (RWFD) buildings
- Past performance of wood diaphragms in RWFD buildings
- Evaluation of past and current building design practices
- Development of a new diaphragm design methodology
- Evaluation of a new design methodology
- Conclusions
- Questions
How to Earn your CEUs/PDHs and Receive Your Certificate of Completion
To receive your certificate of completion, you will need to complete a short on-line post-test and receive a passing score of 70% or higher within 1 year of purchasing the course.
How do I convert CEUs to PDHs?
1.0 CEU = 10 PDHs [Example: 0.1 CEU = 1 PDH]