Probabilistic Models for Infrastructure Risk Assessment and Management in the Changing Climate

基础设施是每个加拿大人日常生活的核心——从建筑、桥梁、供水到交通网络和能源系统，所有这些都对我们社区的经济增长、健康和安全以及生活质量至关重要。现有基础设施大多建于20世纪中期，对其老化的担忧促使人们研究结构可靠性和风险评估方法，以指导基础设施更新战略。否则，如果不及时缓解恶化，失败的风险必然会增加，如佛罗里达州迈阿密多层建筑倒塌（2021年6月）、意大利热那亚莫兰迪大桥倒塌（2018年8月）和蒙特利尔交通隧道混凝土板倒塌（2011年8月）。气候变化的加速加剧了极端天气事件的强度和频率，威胁到现有的基础设施，影响其有效性，缩短寿命，并增加了维修和更新的成本。例如，德克萨斯州（2021年2月）的严重冰暴、不列颠哥伦比亚省利顿创纪录的热浪（2021年6月）将气温推至近50摄氏度的危险水平、西欧（2021年7月15日）前所未有的降雨和洪水以及美国飓风“艾达”（2021年8月31日）造成的降雨和洪水造成许多人死亡并造成巨大财产损失。因此，日益严重的极端天气加剧了老化基础设施失效的风险。为了应对这种累积的威胁，下一阶段的研究建议是通过对加拿大基础设施资产的设计和生命周期管理，在对气候变化带来的风险进行强有力的评估的基础上，提高安全性和弹性。该提案的科学核心是基于概率论和随机过程，这些过程可以模拟由气候变化和各种形式的老化相关结构退化引起的不确定和非平稳载荷。这些模型将预测未来的可靠性和风险，并通过优化系统生命周期的投资来评估维护和修复对安全性和弹性的影响。由于气候变化的“非平稳”性质与现有结构设计规范所使用的平稳假设不相容，本研究将产生知识库，以修订与极端荷载分布、可靠性指标、设计因素和荷载组合规则相关的许多规定，并引导下一代规范的发展。总之，该研究计划的下一个五年阶段将继续建立在先前研究工作的成功基础上，并为基础设施的风险分析和管理发现新的方法和工具。在概率风险和可靠性的高级领域培训七名研究生将是拟议计划的重要成果。

Infrastructure is central to the daily life of every Canadian - from buildings, bridges, and water supply to transportation networks and energy systems, all are vital to the economic growth, health and safety, and quality of life of our communities. Concerns over the aging of existing infrastructure, largely built in the mid-20th century, have prompted research into structural reliability and risk assessment methods for guiding infrastructure renewal strategies. Otherwise, in the absence of timely mitigation of deterioration, the risk of failures is bound to increase, as evidenced by the collapse of a multistorey building in Miami, Florida (June 2021), the collapse of the Morandi bridge in Genoa, Italy (August 2018), and the failure of a concrete slab in a traffic tunnel in Montreal (August 2011). The increasing pace of climate change aggravates the intensity and frequency of extreme weather events, threatening the existing infrastructure, impacting its effectiveness, reducing lifespan, and adding to the cost of repair and renewal. For example, a crippling ice storm in Texas (February 2021), a record-setting heatwave that pushed temperatures to dangerous levels of nearly 50 C in Lytton, BC (June 2021), and unprecedented rainfall and floods in Western Europe (15 July 2021) and those caused by hurricane Ida in the United States (31 August 2021) killed many people and caused huge property damage. Thus, the increased severity of weather extremes exacerbates the risk of failure of aging infrastructure. To respond to this cumulative threat, the next phase of research is proposed to improve safety and resilience through design and life cycle management of Canadian infrastructure assets founded on a robust assessment of risks posed by the changing climate. The scientific core of this proposal is based on the probability theory and stochastic processes that can model uncertain and non-stationary loads resulting from climate change and various forms of aging-related degradation of structures. These models will predict future reliability and risk and evaluate the effects of maintenance and rehabilitation on safety and resilience through optimized investments over the life cycle of a system. As the "non-stationary" nature of the changing climate is incompatible with the assumption of stationarity used by existing structural design codes, the proposed research will generate the knowledge base to revise many provisions related to extreme load distributions, reliability metrics, design factors, and load combination rules, and lead the development of the next generation of codes. In summary, the next five-year phase of this research program will continue to build on the success of the previous research work and discover new methods and tools for risk analysis and management of infrastructure. The training of seven graduate students in the advanced areas of probabilistic risk and reliability will be a significant outcome of the proposed program.