Probabilistic Models for Performance-based Engineering, Applied to Tall Wood Buildings

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The safety and economic security of Canadians depend on the integrity of the built environment. Inadequate performance of structural components in buildings and infrastructure can lead to dramatic consequences and devastating losses. Recent events abroad have served notice to Canadian municipalities. One example is the 2011 earthquake in Christchurch, New Zealand, which caused casualties, monetary losses in excess of $20 billion, and long-term impacts on businesses and regional growth. Similar impacts have been observed when other earthquakes have struck modern urban regions around the world. On this background the increasing urbanization of Canada, particularly in the seismically active regions around Vancouver and Montreal, raises important concerns that are addressed in this proposal. **Structural engineers must balance many concerns, ranging from potential damage and deterioration of buildings to environmental impacts of construction. In fact, a life-cycle viewpoint must be adopted, which considers several direct and indirect costs in conjunction with an array of hazards. A key concern in this proposal is damage due to earthquakes, but the objective is not to seek zero damage. This is because the cost of improving new and existing designs is substantial, both in monetary terms and also in terms of environmental impacts. Moreover, many sources of uncertainty prevent deterministic predictions of what will happen in the future in terms of hazards, structural performance, and costs. As a result, the goal is rather to help engineers identify and communicate the optimum allocation of resources based on a holistic consideration of risk. While this is a broadly accepted ideal, it requires an array of models, many of which are either unavailable or employed only in academic research. Substantial work is therefore required to complement conservative code equations with predictive models. Thus, 375 years since Galileo's first efforts to predict the load capacity of beams, efforts by structural engineers to improve their models are as important as ever. **The vision leading this proposal is that engineers in the future will use computer simulation models of the built environment as a basis for the quantification, mitigation, and communication of risk. The simulations will comprehensively model the hazards that the buildings and infrastructure are subjected to during their life cycle, and the results will quantify the ensuing costs. To address this challenge, an extensive research program is proposed with the aims of improving existing computer models, developing new ones, and unifying both in a holistic analysis framework. Building on the applicant's expertise and a newly developed software platform, particular attention will be devoted to probabilistic analysis. The research outcomes will have broad applicability but the testbed application will be tall wood buildings. Prompted by initiatives in British Columbia, as well as a renaissance in tall wood buildings worldwide, this research will contribute to the safe and sustainable re-introduction of such buildings into seismic regions. The material of choice is cross-laminated timber (CLT), which is a new product with a growing market-share in multi-storey construction. The introduction of CLT comes as building code committees in Canada and around the world are seeking to amend prescriptive design rules with a more performance-based approach. For that reason, and because there is limited experience with tall CLT buildings in seismic regions, this type of construction represents an ideal opportunity to use performance predictions and a holistic consideration of risk as design bases. The development of computer models and tools for this purpose is the principal objective of this proposal.