Development of Fragility Curves for Problems in Geotechnical Earthquake Engineering

本研究项目的目标是为岩土地震工程中的各种问题开发脆弱性曲线，特别是地基、边坡和挡土墙。脆弱性曲线提供了某种类型结构超过规定破坏水平（例如轻微、中度、重大、完全）的概率，作为地震事件严重程度的函数。 从工程应用的角度来看，脆弱性曲线是非常重要的，因为实践工程师可以直接使用它们，而不必执行任何复杂的计算，因为它们构成了民用基础设施系统的所有风险分析/损失估计/风险降低的基础。 虽然已经为建筑物和桥梁等结构建立了脆弱性曲线，但还没有任何系统的努力来开发岩土结构（例如基础，斜坡，挡土墙）的此类曲线。 这样的任务是特别重要的，因为这些结构的损坏是相当广泛的，在大地震事件。经验的脆弱性曲线将计算从最近的地震事件，如：洛马普列塔，北岭，科比，日本，伊兹米特，土耳其和集集，台湾地震可用的损坏数据。 在完成建立经验脆弱性曲线的任务的同时，将使用蒙特卡罗模拟技术计算分析脆弱性曲线。 其中一项重要任务是比较“经验”和“分析”脆弱性曲线，以提高其准确性和可靠性。 将讨论与建立此类岩土结构的脆弱性曲线有关的几个问题，包括每种结构的不同损伤状态的定义和地震事件强度的测量。 将考虑不同的机制，以造成所考虑的岩土结构的损坏。 特别强调土壤液化、由于超过抗剪强度而导致的边坡破坏以及基础和基础系统的倾斜。为一系列岩土结构建立脆弱性曲线将成为此类结构遭受地震时风险分析/损失估计/风险降低的基础。 这些脆弱性曲线将允许公共和私人组织对1）地震对民用基础设施系统的潜在破坏、2）改造策略、3）保险费以及4）指导应急管理团队识别高风险系统进行合理评估。该项目涉及普林斯顿大学和布法罗的纽约州立大学的研究人员之间的合作。

The objective of this research project is to develop fragility curves for a wide range of problems in geotechnical earthquake engineering; specifically, for foundations, slopes, and retaining walls.Fragility curves provide the probability of exceeding a prescribed damage level (e.g. minor, moderate, major, complete) for a certain type of structure, as a function of the severity of the seismic event. Fragility curves are extremely significant from the engineering applications point of view as practicing engineers can use them directly without having to perform any complex computations, and because they form the basis for all risk analysis/loss estimation/risk reduction of civil infrastructure systems. Although fragility curves have been established for structures such as buildings and bridges, there hasn't been any systematic effort to develop such curves for geotechnical structures (e.g. foundations, slopes, retaining walls). Such a task is particularly important, as damage to these structures is quite extensive during major earthquake events.Empirical fragility curves will be computed using available damage data from recent seismic events such as: the Loma Prieta, the Northridge, the Kobe, Japan, the Izmit, Turkey and the Chi-Chi, Taiwan earthquakes. In parallel with the task of establishing the empirical fragility curves, analytical fragility curves will be computed using Monte Carlo simulation techniques. One of the important tasks is to compare the "empirical" and "analytical" fragility curves so as to improve their accuracy and reliability. Several issues related to the establishment of fragility curves for such geotechnical structures will be addressed, including the definition of the different damage states for each type of structure and the measure of the intensity of the earthquake event. Different mechanisms will be considered to cause damage to the geotechnical structures considered. Particular emphasis will be given to soil liquefaction, to slope failure due to exceeding the shear strength, and to tilting of foundations and foundation systems.The establishment of fragility curves for a range of geotechnical structures will form the basis for the risk analysis/loss estimation/risk reduction of such structures, when subjected to earthquakes. These fragility curves will allow public and private organizations to make rational assessment of 1) the potential damage to civil infrastructure systems from earthquakes, 2) retrofitting strategies, 3) insurance premiums, and 4) guide emergency management teams to identify high-risk systems.This project involves a collaboration between researchers at Princeton University and the State University of New York at Buffalo.