Funding information ReLUIS, Grant/Award Number: ReLUISDPC 2019-2021 project; Presidenza del Consiglio dei Ministri—Dipartimento della Protezione Civile (DPC) SUMMARY In performance-based seismic design, as adopted by several building codes worldwide, the structural performance is verified against ground motions that have predetermined exceedance return periods at the site of interest. Such a return period is evaluated by means of probabilistic seismic hazard analysis (PSHA), and the corresponding ground motion is often represented by the uniform hazard spectrum (UHS). The structural performance for ground motions larger than those considered in this design approach is, typically, not explicitly controlled under the assumption that they are sufficiently rare. On one hand, this does not achieve uniform safety at sites characterized by different design ground motions corresponding to the same return period; on the other hand, exceedances of the design spectra are systematically observed over large areas, for example in Italy. The latter issue is because of the nature of UHS, the exceedance of which is likely-to-almost-certain when the construction site is in the epicentral area of moderate-to-high magnitude earthquakes (ie, the design spectrum may be not conservative at these locations), especially if PSHA is based on seismic source zones. The former is partially because of the systematic difference of ground motions for return periods larger than the design one at the different sites. Quantification of the expected ground motion given the exceedance of the design ground motions (ie, the recently introduced as the expected peak-over-threshold or POT) can be of help in quantitatively assessing these issues. In the study, a procedure to compute the POT distribution is derived first; second, POT spectra are introduced and used to help understanding why and how seismic structural reliability of code-conforming structures decreases as the seismic hazard of the site increases; third, expected and 95 percentile POT maps are shown for Italy to discuss how much high hazard sites are exposed to much larger peak-over-threshold with respect to mid-hazard and low-hazard sites; finally the POT is discussed with respect to the slope of the hazard curve (in log-log scale) at the threshold, a known proxy for ground motion beyond design. All data presented in the maps are made available for the interested reader as a supplemental archive.

中文翻译：

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峰值超过阈值：量化超出设计的地面运动

资金信息 ReLUIS，Grant/Award Number：ReLUISDPC 2019-2021 项目；Presidenza del Consiglio dei Ministri—Dipartimento della Protezione Civile (DPC) 总结 在全球多个建筑规范采用的基于性能的抗震设计中，结构性能根据在相关地点具有预定超标重现期的地面运动进行验证。这样的重现期是通过概率地震危险分析（PSHA）来评估的，相应的地震动通常用均匀危险谱（UHS）表示。比这种设计方法中考虑的更大的地面运动的结构性能通常不会在它们足够罕见的假设下明确控制。一方面，在具有与相同重现期相对应的不同设计地面运动特征的场地，这无法实现统一的安全；另一方面，在大范围内系统地观察到超出设计光谱的情况，例如在意大利。后一个问题是由于 UHS 的性质，当建筑工地位于中到高震级地震的震中区时，超标的可能性几乎是肯定的（即，设计频谱可能不保守在这些位置），特别是如果 PSHA 基于震源区。前者部分是因为不同地点的地震动的系统差异大于设计的重现期。给定超出设计地面运动的预期地面运动的量化（即，最近引入的预期峰值超过阈值或 POT）可以帮助定量评估这些问题。在研究中，首先推导出计算 POT 分布的程序；第二，POT 谱被引入并用于帮助理解为什么以及如何随着场地地震危险性的增加符合规范的结构的抗震结构可靠性降低；第三，显示了意大利的预期和 95 个百分点的 POT 地图，以讨论有多少高危地点暴露于相对于中等危险和低危险地点而言更大的峰值超过阈值；最后，根据阈值处的危险曲线斜率（以对数-对数标度）讨论 POT，阈值是超出设计的地面运动的已知代理。地图中显示的所有数据都作为补充档案提供给感兴趣的读者。