砌体结构地震倒塌过程仿真及抗倒塌影响因素

Simulation on collapse process and analysis of anti-collapse influencing factors for masonry structure under earthquake

在强震中砌体房屋易倒塌,为了对其倒塌过程仿真及对影响结构倒塌的因素进行分析,采用显式动力有限元软件ANSYS/LS-DYNA,对某结构模型进行倒塌过程仿真;同时分析了构造柱、砂浆强度、开洞率、块体密度以及窗间墙与窗下墙的刚度比等因素对砌体结构抗倒塌性能的影响。结果表明:在地震作用下,由于门窗洞口处易出现应力集中,故门窗洞口四角处先发生破坏;构造柱可以提高砌体结构的变形能力和整体性;一定程度上,砂浆强度越高,结构越难倒;墙体开洞率越大,越容易倒塌;块体强度一定时,密度相对较小有利于抗倒塌;当窗间墙与窗下墙的刚度比小于1.0时,窗间墙先于窗下墙破坏,窗间墙的破坏会加速结构的倒塌。

It has been obvious that masonry structures are prone to collapse in strong earth- quakes. Simulating collapse process and analyzing anti-collapse influencing factors for masonry structure is significant. The explicit dynamic FE software ANSYS/LS-DYNA was adopted to simulate collapse process. Meanwhile, the effects of tie-column, mortar strength, block density, the rate of holes,the stiffness ratio of window wall to spandrel wall on anti-collapse performance of masonry structure were analyzed. The results show that the corners of windows and doors will be damaged at first where the stress concentration occurs under the action of earthquake; deform- ation capacity and integrity of masonry structure can be improved by tie-columns; to some extent, the higher the strength of mortar, the harder the collapse of structure; the structure is easy to collapse while the ratio of holes on the walls becomes bigger and bigger. For the blocks with cer- tain strength, the smaller the density, the better the seismic capacity. When the stiffness ratio ofwindow wall to spandrel wall is less than 1.0, the window wall will failure firstly and the window wall destruction will lead to faster structure collapse. 5 tabs, 11 figs, 20 refs.