Life-Cycle Damage and Downtime Cost Estimates for Structural Systems Subjected to Seismic Loads

该奖项的主要目标是开发一种准确、高效、概念简单的方法来评估实际结构系统的生命周期抗震性能。这项研究的动机是它有可能为基于性能的抗震设计概念的实际实施做出贡献。研究的第一步是建立一个描述特定地点地震危险性的概率模型。该模型将根据美国地质调查局提供的数据进行校准。该模型将提供在特定时间间隔内可能在特定地点发生的地震事件序列的到达时间、震级和震中位置，以及这些事件期间的地面运动。研究的第二步是在一个地点开发描述概率地震地面加速度记录的降阶模型。由此产生的降阶模型将用于计算系统脆弱性作为地震震级和震中到站点距离的函数，而不是单一的地震烈度参数。这些发展将用于估算实际结构系统的寿命损坏和停机成本，以及评估设计方案的抗震性能。完成的研究将提供一种准确且概念简单的方法来估计结构系统的寿命损坏和停机成本，这是开发基于性能的设计程序的基本要素。除了为基于性能的设计相关研究提供有用的输入外，该项目还可能为分析随机行动下具有不确定特性的复杂、大规模动态系统开辟新的研究方向。本研究中建立的降阶模型可用于设计测试设备和其他随机激励系统的有效协议。这些方案将通过选择这些激励的代表性样本，从指定数量的测试中提取最大的信息。工程专业的研究生和本科生将通过课堂教学、作为研究小组成员参与项目以及项目中开发的软件包，从拟议的研究成果中受益。

The main objective of this award is the development of an accurate, efficient, and conceptually simple methodology for assessing the life-cycle seismic performance of realistic structural systems. The research is motivated by its potential to contribute to the practical implementation of performance-based seismic design concepts. A first step of the research is the development of a probabilistic model describing the seismic hazard at a particular site. The model will be calibrated with the data available from the United States Geological Survey. The model will deliver arrival times, magnitudes, and epicenter locations for the sequence of seismic events likely to occur at a particular site during a specified time interval, as well as ground motions during these events. A second step of the research is the development of reduced order models characterizing probabilistically seismic ground acceleration records at a site. Resulting reduced order model will be used to calculate system fragilities as functions of earthquake magnitudes and epicenter-to-site distances, rather than a single seismic intensity parameter. These developments will be applied to estimate life-time damage and downtime costs for realistic structural systems and construct metrics rating the seismic performance of design alternatives.The completed research will provide an accurate and conceptually simple methodology for estimating life-time damage and downtime costs for structural systems, which are essential ingredients for the developments performance-based design procedures. In addition to providing useful input to performance-based design-related studies, the project is likely to open new research directions on the analysis of complex, large scale dynamic systems with uncertain properties subjected to random actions. The reduced order models developed in this study can be used to design efficient protocols for testing equipments and other systems subjected to random excitations. These protocols will extract maximum information from a specified number of tests by selecting representative samples of these excitations. Graduate and undergraduate engineering students will benefit from results of the proposed research through classroom instruction, participation in the project as members of the research team, and software packages to be developed in the project.