2022年泸定地震某隔震建筑隔震层及上部结构地震反应分析

Seismic Response Analysis of the Isolation Layer and Superstructure of a Base-Isolated Building in the 2022 Luding Earthquake,China

在2022年9月5日四川泸定6.8级地震中,位于震中附近的一栋地上6层地下1层的隔震建筑的隔震层黏滞阻尼器、穿越隔离缝的管线、隔离缝附属非结构构件等发生破坏。在介绍该建筑主要震害的基础上,通过基于简化分析模型和邻近台站实际强震记录的非线性地震反应分析,推测该建筑的最大地震反应,为分析破坏原因提供定量讨论的基础。分析结果表明,该建筑的隔震层在地震中启动工作并在沿结构短边方向发生了逾200 mm的水平变形,对减小上部结构的地震反应发挥了积极作用。隔震层中的12个黏滞阻尼器对于减小隔震层和上部结构反应的减震效果非常有限。由于黏滞阻尼器及其锚固连接的实际力学性能不明,尚无法对其大量破坏的原因得出确定性结论,可能的原因涉及设计、产品、施工等环节。

During the M6.8 Luding earthquake in Sichuan Province,China,on September 5,2022,a multi-story base-isolated building near the epicenter sustained extensive damage to its viscous dampers in the isolation layer,the pipelines crossing the isolation gap,and the nonstructural elements of the isolation joint. This study summarizes the results of nonlinear time-history assessments of the building under the excitation of the strong ground vibrations observed near the site during the Luding earthquake. The estimated seismic responses are related to the in-field observations to provide a quantitative reference for further investigation of the phenomena. The results confirmed that the isolation layer had sustained a lateral drift of no less than 200 mm along the transverse direction of the building. This flexibility effectively reduced the seismic response of the superstructure. The effect of the 12 viscous dampers in the isolation layer in further reducing the responses of the isolation layer and the superstructure was only marginal during the earthquake. Because the actual mechanical performance of the dampers remained unclear,it is not possible to make a conclusive judgement about the reason for the extensive damage to the dampers. Possible reasons may relate to the design,manufacturing,and/or construction quality control.