Probabilistic Modeling of Spatio-temporally Varying Natural Hazard and Risk

大地震、强风和大雪会造成人员伤亡，破坏建筑物和基础设施系统，并中断业务。结构设计规范用于确保结构在自然荷载作用下的破坏概率低于可容忍水平。然而，公众对极端自然事件下多个建筑物倒塌的反应表明，仅考虑单个结构的安全性的设计是重要的，但对于空间分布的建筑物组合和空间扩展的基础设施来说，可能不符合最佳的社会利益。气候和构造特征的不均匀性导致自然灾害和作用于房屋和建筑物的荷载具有时空变化和相关性。风险的概率量化影响着风险评估和设计规范的更新。需要评估灾害对建筑物组合或空间分布式基础设施系统（如输电塔线系统）的影响，以成功实施减轻和减少灾难性损失的政策。该评估促进卓越的设计规范制定，优化资源分配，以减少自然灾害，维持我们的生活水平，并提高社会弹性。***建议的研究项目涉及由极端风、雪和地震事件引起的时空变化的灾害和风险的概率建模。更具体地说，该项目是：A)绘制加拿大的风雪灾害地图和加拿大的设计实践，并开发极端风和地面雪荷载的空间相关模型；B)以实际地震动记录和匹配目标空间相关性和相干性为条件，对三维地震地震动场进行建模和模拟；C)估算地理上不同自然灾害对空间分布的建筑物和基础设施的风险；D)根据一组结构的可靠性和风险校准已编纂的设计准则。该提案的新颖之处包括使用先进技术为加拿大开发新的风和雪灾害地图，推进新的模型和算法，以模拟具有现实空间相关性和一致性的条件三维地面运动场，在现实的时间和地理变化的自然灾害下，对结构组或空间分布式基础设施系统进行定量可靠性和风险评估。并结合先进的不确定性决策理论制定结构设计规范。***本研究项目旨在支持和培养在时空变化的自然灾害威胁下，为社会减少自然灾害，建立和维持一个有弹性的社会做出贡献的研究生。

Large earthquakes, strong winds and heavy snowfalls can cause fatalities, damage to structures and infrastructure systems, and interrupt business. The structural design codes are used to ensure that the failure probability of a structure due to natural loads is below a tolerable level. However, public reaction to collapse of multiple buildings under extreme natural events indicates that design by considering safety of a single structure alone is important, but may not be in the best societal interest for a portfolio of spatially distributed buildings and for infrastructure with spatially extended footprint. Inhomogeneity in climate and tectonic characteristics results in the natural hazards and loads acting on houses and buildings being spatio-temporally varying and correlated. Probabilistic quantification of the hazards influences the assessed risk and the design code updating. The impact of hazards on the portfolio of buildings or spatially distributed infrastructure systems, such as a power transmission tower-line system, needs to be appraised for successful implementation of policies to mitigate and reduce catastrophic losses. The appraisal promotes excellence in design code making, and optimal resource allocation to reduce natural disasters, maintain our standard of living, and improve societal resilience.***The proposed research program deals with probabilistic modeling of spatio-temporally varying hazards and risk due to extreme wind, snow and earthquake events. More specifically, the program is to: A) map wind and snow hazards for Canada and Canadian design practice, and develop spatial correlation models for extreme winds and ground snow loads; B) Model and simulate tri-directional (3D) seismic ground motions fields conditioned on actual ground motion records and matching target spatial correlation and coherency; C) Estimate the risk to spatially distributed buildings and infrastructure under geographically varying natural hazards; and D) calibrate codified design criteria based on reliability and risk of a group of structures. The novelties of the proposal include the development of new wind and snow hazard maps for Canada using advanced techniques, the advancement of new models and algorithms for simulating conditional 3D ground motion fields with realistic spatial correlation and coherency, the quantitative reliability and risk assessment of groups of structures or spatially distributed infrastructure system under realistic temporally and geographically varying natural hazards, and the incorporation of advanced decision theory under uncertainty for making structural design codes.***The funding requested for the research program is to support and train graduate students who will contribute to the society's effort to reduce natural disasters, and to build and maintain a resilient society under the threat of spatio-temporally varying natural hazards.