SGER: A Feasibility Study of Estimation of Structural Systems Reliability Under Hurricane Hazard

PI：Rajagopalan Balaji；科罗拉多大学在飓风面前对结构系统可靠性的评估和预测对我们国家来说是非常重要的。一些公共和私营规划和灾害管理机构需要这些信息来制定发展规划和减灾战略。此外，保险机构也对结构可靠性估计感兴趣，以评估和设定保费水平。结构风险和可靠性模型存在于私营部门，但它们不是公共领域，而且往往是临时性质的。此外，这些模型独立于对飓风频率、强度及其相关特征(如风、降水和洪水)的实际似然估计来评估结构可靠性。因此，确实需要开发一种综合框架，该框架具有现实的飓风轨迹模拟模型和结构风险/可靠性模型，以产生静态(长期)和动态(时变)结构风险，并能够根据其可靠性对结构进行分类。这项研究的目标以需要一个全面和综合框架为动机，拟议研究的目的是论证综合框架的可行性。为此，目标是：1.使用历史飓风轨迹数据来计算在任何所需位置发生事件的概率(事件由超过风速和降雨量的阈值来定义，因为风速是建筑物上的关键载荷因素)。还要根据气候指标估计这些概率[例如，厄尔尼诺南方涛动、北大西洋涛动等]。2.开发不同类别结构(如木材、砖石、混凝土等)的结构荷载概率。基于.Event。概率是从上面发展出来的。3.建立以荷载概率为条件的结构可靠性估计(包括平稳和时变)。这些结果将有助于我们通过飓风轨迹模拟模型来实施这一框架。这项建议试图为面对飓风的结构风险/可靠性评估制定跨学科的框架。这种方法的独特之处在于，它汇集了以下知识：(A)大西洋飓风的可变性(飓风数量和路径)；(B)估计相关组成部分(降水、风、洪水等)的概率。使用非参数函数估计技术，(C)概率结构载荷估计，和(D)结构风险/可靠性评估的贝叶斯技术，以制定长期和时变的风险估计。这种对实际问题的独特和综合的方法是这一建议的主要智力优点。更广泛的影响这项研究的结果将大大有助于将这一框架与随机飓风轨迹模拟模型一起应用于整个美国海岸和不同的结构群。这也将补充联邦应急管理局的HAZUS倡议，以加强国家在自然灾害下的风险评估能力。这些成果将极大地有助于它们对民用基础设施评估领域的知识基础和知识增长的贡献，以及减少飓风造成的风险。

PI: Rajagopalan Balaji; University of ColoradoThe assessment and prediction of structural system reliability in the face of hurricanes are of great interest to our nation. Several public and private planning and disaster management agencies need such information for developmental planning and disaster mitigation strategies. Also, insurance agencies are interested in the structural reliability estimates to evaluate and set premium levels. Models for structural risk and reliability exist in the private sector but they are not public domain, and often they are adhoc in nature. Furthermore, these models evaluate structural reliability in isolation of realistic likelihood estimates of hurricane frequencies, magnitudes and their associated characteristics (such as winds, precipitation and floods). Thus, there is a real need for the development of an integrative framework that has a realistic hurricane track simulation model coupled with a structural risk/reliability model, to generate static (long term) and dynamic (time varying) structural risks and also the capability to classify structures as per their reliability. Objectives of the study With the need for a comprehensive and integrated framework as the motivation, the aim of the proposed study is to demonstrate the feasibility of the integrative framework. To this end the objectives are: 1. Use the historical hurricane track data to compute probabilities of occurrences of .events at any desired location (events are defined by threshold exceedence of wind speed and precipitation, as wind speed are the key loading factors on structures). Also estimate these probabilities conditioned on climate indications [e.g., El-Nino Southern Oscillation, North Atlantic Oscillation etc.]. 2. To develop structural load probabilities on different class of structures (e.g., timber, masonary, concrete etc.) based on .event. probabilities developed from above. 3. To develop structural reliability estimates (both stationary and time varying) conditioned upon the load probabilities. These outcomes will help us in implementing this framework with hurricane track simulation models. Intellectual Merit This proposal attempts to develop cross-disciplinary framework for structural risk/reliability assessment in the face of hurricanes. The approach is unique in that it brings together the knowledge of (a) Atlantic hurricane variability (both in terms of the number of hurricanes and the tracks); (b) Estimating probabilities of associated components (precipitation, winds, flooding etc.) using nonparametric functional estimation techniques, (c) probabilistic structural load estimation, and (d) Bayesian techniques for structural risk/reliability assessment to develop long term and time varying risk estimates. This unique and integrative approach to a practical problem is the main intellectual merit of this proposal. Broader Impacts The outcomes from this study will significantly help in developing applying this framework in conjunction with a stochastic hurricane track simulation model, for the entire US coast and for different structural groups. This will also supplement the HAZUS initiative by FEMA for enhancing the nation.s risk assessment capabilities under natural hazards. These outcomes will be extremely helpful for their contributions to the knowledge base and intellectual growth in the area of civil infrastructure assessment as well as the reduction of risks induced by hurricanes.