Assessment of UBC Seismic Design Provisions Using Recorded Building Motions From Loma Prieta and other Earthquakes

这是一个事后调查项目，旨在从1989年10月洛马普列塔地震中吸取工程教训。这次地震的反应数据，连同其他地震的记录运动，为统一建筑规范（UBC）中的抗震设计程序评估提供了良好的基础。考虑到这一目标，该项目考虑了几座建筑（一座在沃森维尔，三座在圣何塞），这些建筑都有这样的强震记录。一种系统识别方法（称为MODE-ID）将被应用于估计振动的正常模态。对于每座建筑，模型力、倾覆力矩、层间漂移、横向力和扭转力矩的最佳估计将在整个建筑的每层水平进行。这些量的变化，连同模态周期和阻尼比，在激励水平范围内将被评估。这些结果将与：(1)建筑物抗侧力体系的类型有关；(2)建筑的竖向不规则；(3)每次地震时建筑物的观测抗震性能。这些信息将用于评估当前（1988年）UBC和建筑原始设计中使用的UBC版本的程序和设计参数。这项工作将根据实际现场性能数据，对现有UBC地震设计规定的有效性进行关键评估。

This is a post-event investigation project to learn engineering lessons from the Loma Prieta earthquake (October 1989). Response data from this earthquake, together with recorded motions from other earthquakes, provides an excellent basis for evaluating seismic design procedures in the Uniform Building Code (UBC). With this objective in mind, this project considers several buildings (one in Watsonville and three in San Jose) where such strong motion records are available. A system identification method (named MODE-ID) will be applied to estimate normal modes of vibration. For each building, the optimal estimates of the model forces, overturning moments, interstory drifts, and lateral forces and torsional moments at each floor level throughout the building will be made. The variation of these quantities, together with the modal periods and damping ratios, over the range of excitation levels will be assessed. These results will be correlated with: (1) the building's type of lateral force resisting system; (2) the vertical irregularities in the building; and (3) the building's observed seismic performance during each earthquake. This information will be used to assess procedures and design parameters in the current (1988) UBC and the version of the UBC that was used in the building's original design. This effort will provide a critical assessment of the validity of the existing UBC seismic design provisions based on the real-world field performance data.