Wave Loads and Structural Fragility Behind Impermeable and Permeable Obstacles

风暴潮和海啸造成的洪水给美国和世界各地的建筑物和基础设施造成了巨大的破坏。减少损害和降低整体风险仍然是沿海社区现在和未来的优先事项，但这些目标在某种程度上受到工程设计和分析工具的限制。众所周知，风暴和海啸造成的破坏会在建筑物或植被后面减弱，但事实证明，将这一普遍知识转化为工程师和规划人员的具体指导方针和标准是非常困难的。该项目将使用理论、数值模型以及现场和实验室测量的结果来调查遮蔽结构后面的损害减少程度。该分析的两个显著特征是在事件期间考虑遮挡障碍物的退化，以及允许针对不同风险级别进行设计的概率分析框架。对避风结构的载荷进行有效的量化将消除对洪水事件进行准确设计和规划的主要障碍。这个项目将有助于改善负荷估算，这将直接适用于许多工程设计实例。与地震等灾害不同，风暴波或海啸的淹没事件（IE）负荷可以在0（10米）的尺度上变化，并且受到周围自然和建筑环境的极大影响。计算局部危险和局部荷载的不确定性仍然是确定规划和结构设计脆弱性的最大障碍：与裸地条件相比，障碍物后面的荷载已显示出显着减少，但这些减少尚不能对一般条件进行量化。当考虑到一些障碍物可能会渗透到流动（植被），或者在IE过程中可能会降解，从而改变负载时，预测变得更加困难。该项目将使用(1)缩放和理论分析来检查位于单排障碍物后面的结构的IE危险强度、载荷和脆弱性；(2)计算流体力学模拟；(3)结构分析；(4)现有的现场和实验室数据。分析将使用障碍物本身的脆弱性模型进一步考虑障碍物退化的影响。结果将考虑使用代理建模的不确定性，这将阐明负载和脆弱性不确定性的主要因素，并将提出改进结果的途径。

Inundation from storm waves and tsunamis has caused great damage to buildings and infrastructure both in the United States and worldwide. Reduction of damage and overall risk mitigation remain priorities for coastal communities now and in the future, but these goals are in some ways limited by engineering design and analysis tools. Damage from storm waves and tsunamis is well known to be diminished behind structures or vegetation, but it has proven surprisingly difficult to translate this general knowledge to specific guidelines and standards for engineers and planners. This project will use theory, numerical models, and results from field and laboratory measurements to investigate the degree of damage reduction behind sheltering structures. Two notable features of this analysis will be the consideration of sheltering obstacle degradation during an event, and a framework for probabilistic analysis that will allow design for different levels of risk. Useful quantification of loading for sheltered structures will remove a major impediment to accurate design and planning for inundation events. This project will help to improve load estimates in ways that will be directly applicable to many instances of engineering design.Unlike hazards such as earthquakes, Inundation Event (IE) loading from storm waves or tsunamis can vary on scales of O(10m), and is greatly affected by the surrounding natural and built environments. Uncertainty in computing the local hazard and local loading remains the greatest obstacle in determining fragility for planning and structural design: Loads behind obstacles have been shown to decrease significantly when compared those from bare-earth conditions, but these decreases cannot yet be quantified for general conditions. Prediction becomes even more difficult when considering that some obstacles may be permeable to flow (vegetation), or may degrade over the course of the IE, changing loading. This project will examine IE hazard intensities, loading, and fragility for structures located behind a single row of obstacles using (1) Scaling and theoretical analyses; (2) Computational fluid dynamics simulations; (3) Structural analyses; (4) Existing field and laboratory data. Analyses will further consider the effects of obstacle degradation using fragility modeling of the obstacle itself. Results will consider uncertainties using surrogate modeling, which will both illuminate the major factors in loading and fragility uncertainties, and will suggest avenues through which results might be improved.