无筋砌体农居地震弹塑性有限元研究

Elasto-plastic finite element analysis of unreinforced masonry farmhouse under earthquake

利用ABAQUS软件对既有的砌体墙试验结果进行了数值模拟,验证了模型的正确性以及混凝土损伤塑性模型对模拟砌体结构受力性能的可用性。在此基础上,借助实地调查获得的结构参数和材料性能数据,以重庆典型农居建筑为例,建立了无筋砌体农居的三维有限元模型,对数值模型进行了动力特性分析和不同烈度下多遇及罕遇地震的动力弹塑性时程分析,并建议了无筋砌体结构农居在不同地震烈度破坏下墙体表面积受拉损伤率的临界值。最后,利用既有文献提出的层间位移角限值,分析了该农居的破坏程度,比较了墙体表面积受拉损伤率和层间位移角限值衡量砌体结构的破坏程度。分析结果表明:提出的墙体表面积受拉损伤率和层间位移角限值衡量砌体结构破坏程度吻合良好;当墙体表面积受拉损伤率小于1%时,结构轻微破坏;当位于1%~5%时,发生中等程度破坏;当位于5%~30%时,发生严重破坏;当大于30%时,结构倒塌。

The study analyzed existing masonry wall test results by ABAQUS software and verified proposed numerical models and the feasibility of using the concrete damage plastic model in the simulation of masonry structure failure.Taking Chongqing’s typical masonry farmhouse as an example and using structural parameters and material performance data obtained from field surveys,the study established a three dimensional finite element model of the unreinforced masonry farmhouse,and analyzed its dynamic characteristics and elastic-plastic dynamic behavior at different earthquake intensities.The critical values of surface tensile damage rate of unreinforced masonry farmhouse under different tensile damage degree were proposed.Using the inter storey drift ratio limit obtained from the literature,the damage degree of masonry farmhouse was analyzed and compared with the results based on the proposed damage rate of the masonry wall.The results showed that damage types obtained by the proposed wall surface tensile damage rate and inter storey drift ratio limit were consistent.The study suggested the failure degree of unreinforced masonry farmhouse could be considered as slight damage,moderate damage,severe damage and collapse when the wall surface tensile damage rate was less than 1%,1%-5%,5%-30%,higher than 30%,respectively.