近断层混凝土结构连续性地震倒塌机理研究

项目名称： 近断层混凝土结构连续性地震倒塌机理研究

项目编号： No.51478222

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 建筑环境与结构工程学科

项目作者： 李鸿晶

作者单位： 南京工业大学

项目金额： 85万元

中文摘要： 近断层地震动含有明显的速度和位移脉冲成分，对结构的弹塑性行为和失效倒塌破坏性态具有重大影响。本项目紧密围绕大震不倒的工程抗震设防目标，针对位于近断层区域的钢筋混凝土结构，系统研究结构发生倒塌及连续倒塌破坏的灾变过程及其机理。首先，通过近断层强震观测数据分析和地震动数值模拟两条途径，认识近断层地面运动特有的速度脉冲等特性；其次，通过反映近断层地震动特性的伪静力实验和钢筋混凝土结构精细化弹塑性地震反应分析，发展基于累积损伤效应的塑性铰模型，建立钢筋混凝土结构动态行为分析模型；再次，通过结构弹塑性地震需求谱分析和结构动态反应数值模拟，研究近断层地震特性对结构非线性反应的影响，认识钢筋混凝土结构在近断层地面运动作用下的损伤、破坏直至倒塌的灾变演化发展全过程；最后，通过结构转换模式分析，研究钢筋混凝土结构两类连续倒塌发生机理，即由于局部倒塌引起的连续倒塌机制和由于坠落物体撞击引起的连续倒塌机制。

中文关键词： 混凝土结构；连续性倒塌；近断层地震动；大速度脉冲；地震损伤

英文摘要： Near-fault ground motions contain often large velocity and displacement pulses, which result significantly difference in the elastic-plastic behaviors and failure mechanism of the seismic structures from those located in the far field. In this project, the damage and progressive collapse behaviors of reinforced concrete structures located in the near fault region are investigated in order to satisfy the needs that the structures should not collapse during a severe earthquake. First the characteristics of the near-fault ground motions such as forward directivity and fling effect are researched by analysis of the instrumented ground motion data and numerical simulation of near-fault ground motions. Then a plastic hinge model considering the cumulative damage effect of the structure is developed on the basis of the quasi-static cyclic test, and the dynamic behavior of the reinforced conrete structure subjected to the near-fault ground motion is simulated numerically by finite element method, so that the process of the structural response including damage, failure and collapse is evaluated. The influence of the near-fault ground motion to the response of single-degree-of-freedom system is also checked compared with those due to far-fault ground motion. Finally, two progressive collapse mechanisms of the reinforced concrete structures located in the near fault area are investigated, one of them is that the progressive collapse during an earthquake is caused by failures of local members because of the lack of structural integrity and/or redundancy, another by impacts of the falling objects separated from the structures due to the earthquake induced severe vibrations of the structures.

英文关键词： RC structures;progressive collapse;near-fault ground motion;large velocity pulse;seismic damage