Performance-based Multi-Hazard Engineering for Seismic and Wind Loads

该项目的总体目标是在地震和风暴的多重危险分析的背景下，探索和推进基于性能的工程的最新技术。基于性能的工程是一个成熟的概念，要求结构满足特定的目标，具体取决于地震/风暴荷载的强度。如果没有有效的方法来量化结构荷载中的不确定性并将这种不确定性传播到响应统计中，这一概念的实际实施是不可能的。在过去的二十年里，荷载不确定性的量化及其在结构系统中的传播都取得了重大进展。然而，还需要研究以概率方式描述地震/风荷载，量化材料/结构的不确定性，并计算响应统计。这项拟议的研究将加强首席调查员在之前的国家科学基金会资助下所做的初步工作。该项目将解决不确定性的量化和传播问题，并将它们整合到一种实用的多危险分析方法中。任务1将为地震/风力灾害和负荷开发新的概率模型，这些模型以所有现有信息为基础，能够更准确地捕捉这些负荷的基本特征。灾害和荷载将通过两个参数进行概率描述：地震荷载的力矩震级和震源到场地的距离，以及风力荷载的速度和方向。任务2将开发概念上简单、准确、非侵入性和计算高效的方法，用于计算线性/非线性区域中结构系统在高斯/非高斯载荷下的响应统计、易损性和损伤/成本/停机时间概率分布。该方法基于随机降阶模型，可以看作是一种智能的蒙特卡罗模拟。任务3将利用前两项任务的结果，为地震和风荷载的基于性能的多种危险工程实施一种实用方法。该任务将计算损坏、成本、停机时间、健壮性、恢复和其他性能/恢复指标的概率分布。稳健性和恢复性是结构/非结构系统承受极端事件而功能损失有限的能力，以及将这些系统的功能恢复到事件前水平所需的时间。将使用概率分布，而不是预期，因为它们为决策提供了改进的工具。

The overall objective of the project is to explore and advance the state-of-the-art in performance-based engineering in the context of multi-hazard analysis for earthquakes and windstorms. Performance-based engineering is a maturing concept requiring structures to meet specified objectives depending on the intensity of earthquake/windstorm loads. Practical implementation of this concept is not possible without the availability of efficient methods for quantifying the uncertainty in structural loads and propagating this uncertainty into response statistics. The last two decades have seen significant developments in both the quantification of load uncertainty and its propagation through structural systems. However, research is needed to describe earthquake/wind loads probabilistically, quantify material/structural uncertainties, and calculate response statistics. The proposed research will enhance preliminary work done by the Principal Investigator under a previous NSF grant.The project will address uncertainty quantification and propagation and integrate them in a practical methodology for multi-hazard analysis. Task 1 will develop novel probabilistic models for seismic/wind hazards and loads that are based on all available information and are capable of capturing with increased accuracy the essential features of these loads. Hazards and loads will be characterized probabilistically by two parameters: moment magnitude and source-to-site distance for seismic loads and speed and direction for wind loads. Task 2 will develop conceptually simple, accurate, non-intrusive, and computationally efficient methods for calculating response statistics, fragility and damage/cost/downtime probability distributions, for structural systems in the linear/nonlinear regime under Gaussian/non-Gaussian loads. The method is based on stochastic reduced order models, and can be viewed as a smart Monte Carlo simulation. Task 3 will use results from previous two tasks to implement a practical methodology for performance-based multi-hazard engineering for seismic and wind loads. The task will calculate probability distributions for damage, cost, downtime, robustness, recovery, and other performance/resilience metrics. Robustness and recovery characterize the ability of structural/non-structural systems to withstand extreme events with limited loss of function and the time needed to restore the functionality of these systems to their pre-event level. Probability distributions, rather than expectations, will be used since they provide refined tools for decision making.