Current seismic design requirements were established considering mainly (almost exclusively) ground motions caused by shallow crustal earthquakes, hence they might lead to different-from-intended risk levels when applied at locations prone to large-magnitude subduction (i.e. megathrust) earthquakes. In this study, the seismic behavior of 40 modern steel special moment frames (SSMFs) subjected to both megathrust and crustal ground motions is evaluated. Three analyses are performed: (1) a hazard-consistent analysis; (2) a comparative collapse risk evaluation; and (3) a performance evaluation following the approach indicated in Federal Emergency Management Agency (FEMA) P695. Results indicate that the collapse probability of mid- and high-rise SSMFs subjected to megathrust ground motions is indeed larger than that under crustal ground motions. Modifications to the current design criteria are then suggested, intended not only for United States but also for countries, such as Ecuador, where the US seismic design requirements for steel structures were adopted and seismic ground motions are actually caused by megathrust earthquakes.

中文翻译：

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超强地震作用下钢特殊力矩框架的地震表征

当前的抗震设计要求主要（几乎完全是）考虑由浅地壳地震引起的地面运动，因此当它们应用于容易发生大强度俯冲（即超逆冲）地震的位置时，可能会导致与预期不同的风险水平。在这项研究中，评估了 40 种现代钢特殊力矩框架 (SSMF) 承受超强推力和地壳地面运动的地震行为。进行了三种分析：(1) 危害一致性分析；(2) 比较倒塌风险评估；(3) 按照联邦紧急事务管理局 (FEMA) P695 中指明的方法进行的绩效评估。结果表明，中高层SSMF在超强地震动作用下的倒塌概率确实大于地壳地震作用下的倒塌概率。