An integrated framework for 3D time history analysis of steel special moment-resisting frame buildings under sequential flood and earthquake hazards

With climate change intensifying risks of extreme precipitation and riverine flooding, reassessing building resilience under multi-hazard scenarios, particularly those involving earthquakes, has become increasingly important. This study proposes an integrated framework for three-dimensional (3D) nonlinear time history analysis (NLTHA) to evaluate structural performance under sequential earthquake and flood events. By coupling advanced Computational Fluid Dynamics (CFD) simulations with earthquake engineering methods, the framework captures the time-dependent interaction of seismic and hydrodynamic forces. This overcomes limitations of previous research that relied on oversimplified flood-earthquake interaction models. The analysis focuses on steel special moment-resisting frame (SMRF) buildings in Los Angeles, California. Thirteen seismic hazard levels and four flood inundation depths are analysed, producing detailed engineering demand parameters (EDPs) for both earthquake-only and combined hazard scenarios. Structural vulnerability is evaluated through ductility and plastic hinge rotation in columns and beams. Results show flooding significantly amplifies EDPs, especially in lower stories and front-facing elements, emphasising the need to revise design and assessment strategies for buildings in flood-prone areas. Furthermore, vortex shedding and asymmetric water flow patterns around corners and side columns increase localised hydrodynamic pressures. This integrated approach provides engineers with a comprehensive framework for analysing structures to withstand future climate-driven multi-hazard events.

随着气候变化加剧极端降水与河流洪水风险，在多灾害场景（尤其是涉及地震的场景）下重新评估建筑抗灾能力已愈发重要。本研究提出了一套用于三维（3D）非线性时程分析（NLTHA）的集成框架，以评估地震与洪水相继发生场景下的结构性能。通过将先进的计算流体动力学（CFD）模拟与地震工程方法相结合，该框架能够捕捉地震力与流体力随时间变化的相互作用，弥补了过往研究依赖过于简化的震洪相互作用模型所存在的局限。本次分析聚焦于美国加利福尼亚州洛杉矶市的钢特制抗弯框架（SMRF）建筑，共分析了13种地震危险等级与4种洪水淹没深度，为纯地震灾害场景与复合灾害场景分别生成了详细的工程需求参数（EDPs）。研究通过柱与梁的延性及塑性铰转角评估结构脆弱性，结果表明洪水会显著放大工程需求参数，尤其在低层结构与临街构件中，这凸显了针对易受洪水影响区域的建筑修订其设计与评估策略的必要性。此外，建筑拐角与侧柱周围的涡旋脱落与非对称水流模式会加剧局部流体力荷载。该集成方法为工程师提供了一套全面的分析框架，用于评估建筑抵御未来气候驱动型多灾害事件的能力。