The seismic and wind design provisions for engineered wood structures in Canada have to be enhanced to be compatible with those already available for structures built according to other material standards. Such design provisions are of vital importance for ensuring the competitive position of timber structures relative to reinforced concrete and steel structures. This report provides information on the framework needed for development of such enhanced provisions for design of lateral load resisting systems in engineered wood buildings. Although the framework presented here is suggested for implementation in the Canadian wood design standard (CSAO86) in correlation with the National Building Code of Canada (NBCC - the Canadian model design code), the information provided can be used as a template for other national and international codes and standards.
In the beginning, a comprehensive review on the development of the seismic design procedures in Canada and the US is presented. This is followed by the information on seismic design principles and methods of seismic analysis throughout the world. In addition, a state-of-the-art survey is included on the development and current activities related to the performance based design procedures throughout the world. This is followed by the details that should form the new design section on lateral load resisting systems (LLRS) to be developed in CSAO86 during the next code cycle. It is suggested that in response to the changes already in place in the 2005 edition of the NBCC, besides systems such as shearwalls and diaphragms, the section should include subsections for braced frames and moment resisting frames. It is also suggested that a strong link should be made between the design section on connections and the new one on LLRS. Future editions of the CSAO86 should also be encouraged to use the reliability and performance based design provisions, as the codes in the area of seismic design worldwide are moving in that direction.
There are several ongoing research activities in the field of wood-based lateral load resisting systems and connections throughout Canada and the US. Cooperation between researchers, engineering community and regulatory representatives is vital for successful delivery of the design guidelines mentioned above.