Regional seismic loss assessment is crucial for developing earthquake emergency plans, which can significantly reduce casualties and socioeconomic losses in urban communities. Due to the complex types of building structures in a region, it is not possible to accurately measure the damage state of building structures using a single scalar ground motion intensity measure (IM). To more accurately reflect the responses of structures under earthquake excitations, the seismic fragility surface models for 4 typical RC frame structures are developed based on the vector ground motion IMs. The results indicate that the fragility surface model offers a superior level of precision in capturing the inherent uncertainty of ground motion and subsequently determines a more precise probability of structural failure, outperforming traditional single scalar ground motion IM fragility curve models. This enhanced accuracy holds significant implications for regional loss assessment. To fully consider the spatial cross-correlation of vector ground motion IMs, based on the established ground motion database of 8778 records, principal component analysis (PCA) and geostatistical analysis methods are used to construct a spatial cross-correlation influence field that simultaneously considers multiple ground motion IMs to simulate more realistic earthquake scenarios. Considering the impact of uncertainty in loss ratio on earthquake-induced direct economic loss estimation results, the maximum entropy technique is used in conjunction with an improved Latin Hypercube Sampling (LHS) to achieve spatially uniform sampling of loss ratio (LR). This study proposes an assessment framework for regional seismic direct economic loss for portfolio buildings based on the seismic fragility surface model considering spatial cross-correlation and uncertainty of loss ratio. The proposed framework is verified by numerical examples, and it is proven that the regional portfolio buildings considering multiple ground motion IMs is more reliable and robust than those merely considering a single ground motion IM, and when spatial cross-correlation is not considered, the probability of serious economic losses will be underestimated.

中文翻译：

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基于地震脆性表面的投资组合建筑地震引起的直接经济损失估算


区域地震损失评估对于制定地震应急计划至关重要，这可以显著减少城市社区的伤亡和社会经济损失。由于一个地区建筑结构类型复杂，无法使用单个标量地震动强度测量 （IM） 准确测量建筑结构的损伤状态。为了更准确地反映结构在地震激励下的响应，基于矢量地震动 IM 开发了 4 种典型 RC 框架结构的地震脆性面模型。结果表明，脆性表面模型在捕获地震动的固有不确定性方面提供了卓越的精度，并随后确定了更精确的结构失效概率，优于传统的单标量地震动 IM 脆弱性曲线模型。这种提高的准确性对区域损失评估具有重要意义。为充分考虑矢量地震动IMs的空间互相关，基于已建立的8778条地震动数据库，采用主成分分析（PCA）和地统计分析方法构建同时考虑多个地震动IMs的空间互相关影响场，以模拟更真实的地震情景。考虑到损失率的不确定性对地震引起的直接经济损失估计结果的影响，将最大熵技术与改进的拉丁超立方体采样 （LHS） 结合使用，以实现损失率 （LR） 的空间均匀采样。 本研究提出了一个基于考虑空间互相关和损失率不确定性的地震脆性面模型的投资组合建筑区域地震直接经济损失评估框架。所提出的框架通过数值算例进行了验证，证明考虑多个地震动 IM 的区域组合建筑比仅考虑单个地震动 IM 的区域组合建筑更可靠、更鲁棒，当不考虑空间互相关时，严重经济损失的可能性将被低估。