酸雨环境下砌体结构地震易损性研究

对4榀相同特性的砖墙进行不同程度的酸雨腐蚀试验及低周反复荷载试验,得出其在不同腐蚀循环次数下的滞回曲线。基于陆新征-曲哲恢复力模型对砖墙试件进行模拟分析,并与试验结果进行对比,验证得出三弹簧单元模型能够较准确预测砌体构件的滞回性能。利用三弹簧单元模型对不同腐蚀次数下砌体结构进行IDA分析,得出不同腐蚀次数下砌体结构的易损性曲线,通过对"小震"、"中震"、"大震"下结构失效概率的分析得出,酸雨腐蚀能够严重影响结构的力学性能,使得结构的抗震性能显著下降。

Seismic Vulnerability of Masonry Structures Subjected to Acid Rain

Because of environmental pollution, the frequency of acid rain is increasing. In rural areas and small towns in China, many ancient buildings are masonry structures that are easily corroded by acid rain. Because of the poor seismic performance of masonry structures subjected to acid rain, research on these structures corroded by acid rain has become increasingly important. In this study, we designed four brick walls with common characteristics and tested them with a series of 0, 100, 200, and 300 corrosion cycles of acid rain. Then, using a low reversed cyclic loading test, we obtained the hysteresis curve of the four brick walls under these corrosion cycles. Based on the three-spring element model combined with the Lu Xinzheng-Qu Zhe restoring force model, we used the finite element software Marc to simulate the response of the brick walls. Our experimental results proved that the three-spring element model can accurately predict the hysteretic properties of masonry structures. To verify the rationality of using the three-spring element model to simulate the whole structure, we used it to construct a finite element model of a teaching building for modal analysis and compared it with the ABAQUS modal analysis results of previous research. Our results show that the three-spring element model can better reflect basic dynamic structural characteristics and satisfy requirements for nonlinear earthquake analysis. We also summarize domestic and overseas drift allowance angles of different damage states combined with our experimental results and China''s national code to demarcate appropriate drift allowance angles. We used 15 seismic waves from the ATC-63 project to perform an incremental dynamic analysis of structures and to obtain seismic vulnerability curves under different corrosion cycles. Based on our analysis of the failure probability for different structural damage states from small, medium, and large earthquakes, acid rain can seriously affect structural mechanical properties and significantly reduce seismic performance.