基于试验测量的高层结构整体抗震损伤评估

结构的损伤模型可以从材料、构件和整体三个层次研究。整体结构损伤模型主要以结构整体为研究对象,从结构的整体反应参数变化研究结构整体性能的变化规律,并对在地震作用下结构的损伤、抗震性能进行分析。结构损伤时物理参数的变化,必将引起动力参数的变化。因此可以通过动力测试来捕捉结构动力参数的变化,如:结构损伤前后固有频率、模态振型和阻尼的变化,可以进行结构损伤诊断。结合在同济大学土木工程防灾国家重点实验室做过的几十个模拟地震振动台试验测试结果,统计和总结地震作用下高层建筑结构自振频率与阻尼比的变化规律,提出了一种新的损伤模型与损伤指标。该损伤模型综合考虑了高阶振型、振型参与系数、结构自振频率、阻尼比等影响因素。最后,用该损伤模型和损伤指标对其中3个典型的高层建筑结构模型模拟地震振动台试验数据进行验证,结果表明:该损伤模型与试验现象基本吻合。可对既有工程结构快速准确地进行动力损伤识别与评估。

Seismic Damage Assessment of High-Rise Structures Based on Experimental Measurements

There are three types of building damage model based on materials,components and overall structure.The overall structural damage model is studied on the whole structure as an object.Structural responses of inherent property parameter and their variations are reflected in the overall structural performance.And the structural seismic performance and its damage are analyzed before earthquake and after different levels of earthquake.Due to injury or even damage after earthquake,some changes in the structural inherent property parameter are incurred,leading to some changes in dynamic parameter responses.Therefore,to capture dynamic parameters in the dynamic structural testing,such as,inherent frequencies,mode shapes and damping,can diagnose the structural damage.Combined with dozens of shaking table test results,tested in the State Key Lab for Disaster Reduction in Civil Engineering,in Tongji University,the variations of inherent frequency and damping ratio of tall buildings under earthquake has been counted and summarized.Then,a new damage model and damage index are proposed,considering higher modes,mode participation factors,the inherent frequencies,damping ratios and other factors.Finally,to validate the damage model and damage index,they are used in the model shaking table test data three typical high-rise building structures.The results show that the damage model and index is consistent with the experimental phenomena.So,it can be applied to the existing structure to identify and assess the dynamic damage quickly and accurately.