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

PI: Rajagopalan Balaji；面对飓风时结构系统可靠性的评估和预测是我国非常感兴趣的问题。一些公私规划和灾害管理机构需要这类信息来制定发展规划和减灾战略。此外，保险机构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，但不属于公共领域，而且往往是临时性的。此外，这些模型在不考虑飓风频率、震级及其相关特征（如风、降水和洪水）的现实可能性估计的情况下评估结构可靠性。因此，确实需要开发一个综合框架，该框架具有真实的飓风轨迹模拟模型和结构风险/可靠性模型，以生成静态（长期）和动态（时变）结构风险，并具有根据其可靠性对结构进行分类的能力。以需要一个全面和整合的框架为动机，拟议研究的目的是证明整合框架的可行性。为此目的，目标是：使用历史飓风轨迹数据来计算发生的概率。任何期望位置的事件（事件由风速和降水的阈值超过定义，因为风速是对结构的关键载荷因素）。还要根据气候指示估计这些概率[例如，厄尔尼诺-南方涛动、北大西洋涛动等]。2. 开发基于.event的不同类型结构（如木结构、砖石结构、混凝土等）的结构荷载概率。概率从上面发展而来。3. 建立基于荷载概率的结构可靠度估计（包括平稳和时变）。这些结果将有助于我们在飓风路径模拟模型中实施这一框架。本提案试图开发面对飓风的结构风险/可靠性评估的跨学科框架。这种方法的独特之处在于，它汇集了以下方面的知识：(a)大西洋飓风的可变性（飓风的数量和路径）；(b)使用非参数函数估计技术估计相关组件（降水，风，洪水等）的概率，(c)概率结构负载估计，以及(d)用于结构风险/可靠性评估的贝叶斯技术，以开发长期和时间变化的风险估计。这种解决实际问题的独特而综合的方法是这一建议的主要智力优点。更广泛的影响本研究的结果将极大地有助于将该框架与随机飓风路径模拟模型结合起来，用于整个美国海岸和不同的结构群体。这也将补充联邦应急管理局的HAZUS倡议，以增强国家。自然灾害下的风险评估能力。这些成果将非常有助于为民用基础设施评估领域的知识库和智力增长以及减少飓风造成的风险作出贡献。

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.