Quantifying the seismic fragility, risk, and resilience of structures is a computationally demanding step in the performance-based earthquake engineering framework as it commonly requires a large number of nonlinear dynamic analyses. The Endurance Time Method (ETM), which leverages just a small number of intensifying dynamic loads to obtain full responses of structures from elastic to collapse, has been increasingly used recently for efficient estimates of seismic responses. However, when applied to fragility analyses, ETM may produce imprecise fragility medians and under-estimated dispersions in fragility curves, which thereby results in biased estimates of risk and resilience. To solve this problem, the present study develops an Enhanced ETM (EETM) specialized for accurate and efficient seismic fragility analyses, which further boost accurate and efficient assessment of structural risk and resilience. The developed method is demonstrated using a computationally intensive deep water-bridge model under earthquakes considering the fluid-structure interaction. Merits of EETM on efficiency and accuracy are demonstrated by comparison with ETM and Incremental Dynamic Analysis (IDA) method.

量化结构的地震脆性、风险和弹性是基于性能的地震工程框架中计算要求高的步骤，因为它通常需要大量非线性动力分析。耐久时间法 (ETM) 仅利用少量强化动态载荷来获得结构从弹性到倒塌的完整响应，最近越来越多地用于有效估计地震响应。然而，当应用于脆弱性分析时，ETM 可能会产生不精确的脆弱性中位数和脆弱性曲线的低估离散度，从而导致对风险和恢复力的估计有偏差。为了解决这个问题，本研究开发了一种增强型 ETM (EETM)，专门用于准确有效的地震脆性分析，这进一步促进了对结构性风险和弹性的准确和有效评估。所开发的方法在考虑流固耦合的地震下使用计算密集型深水桥模型进行了演示。通过与 ETM 和增量动态分析 (IDA) 方法的比较，证明了 EETM 在效率和准确性方面的优点。