Lepper, M. and Jones, E.
2000 World Conference on Timber Engineering, Whistler Resort, British Columbia, Canada, July 31 - August 3
Lepper, M. and Jones, E., (2000), "Objective-based codes for wood frame construction", World Conference on Timber Engineering, Whistler Resort, British Columbia, Canada, July 31 - August 3.
Abstract:
The National Building Code of Canada (NBCC) is undergoing a transition to a new "Objective-based" framework. The Objective-based format is being adopted to address the increasing complexity of codes, clarify the intent of the code requirements, allow for innovative design and rationalize the existing code structure. The transition process includes analysis of existing requirements for underlying intents, and review of th e basic objectives in the Code.
This conversion presents a challenge to experience-based contents of the existing Code such as the wood-frame structural provisions for houses and small buildings. Many of these provisions are embedded in prescriptive clauses and tables that are deemed to satisfy Code requirements. The prescriptive approach makes it difficult to implement new products and innovative designs. The increasing complexity of house design and other small buildings has led engineers and building officials to question the scope of t he prescriptive requirements.
The vast majority of one and two family dwellings in Canada are built using the wood frame prescriptive requirements in the National Building Code. Using traditional engineering designs, the resistance of these buildings to wind and earthquake lateral loads cannot be calculated although history has illustrated that this type of construction has excellent resistance to lateral loads. The Canadian Wood Council has developed a Guide for Wood Frame Construction. The Guide provides structural design solutions for buildings that fall outside the basic objectives of the prescriptive requirements in the National Building Code of Canada and gives guidelines for determining when engineering solutions should be used instead of traditional prescriptive requirements. In order to help explain how wood frame construction resists lateral loads, the Canadian Wood Council has also sponsored a number of research projects. Two of these projects - The Performance of Wood Buildings with 4:12 Pitched Roofs Under Extreme Wind Loads and Analysis of Lateral Resistance of Wood Framed Diaphragms - will be described in this paper.