填充墙RC框架结构抗连续性倒塌性能数值模拟研究

Numerical study on progressive collapse performance of infilled RC frame

为研究填充墙钢筋混凝土(RC)框架的抗连续性倒塌性能,对其进行了数值模拟研究。基于LS-DYNA软件,建立了填充墙RC框架的连续性倒塌分析的精细化有限元模型。模型中采用连续面盖帽模型模拟砖砌体,采用接触算法模拟砂浆。通过对4榀1/4缩尺的RC框架(两榀纯框架和两榀带填充墙框架)的Pushdown试验结果进行模拟分析,验证了有限元模型的精度,并分析了填充墙厚度和砌体强度对RC框架抗连续性倒塌性能的影响。分析结果表明:在所有失柱工况中,失去中柱的填充墙RC框架抗连续性倒塌的峰值荷载最大,填充墙对失去中柱的RC框架的提高作用有限;在移除角柱工况下,填充墙RC框架的抗连续性倒塌峰值荷载最小,填充墙对失去角柱的RC框架的提高作用显著。填充墙厚度比砌体强度对RC框架抗连续性倒塌峰值荷载的提升作用影响更为显著。

The progressive collapse behavior of RC frame with infilled walls was investigated using numerical simulation. Based on LS-DYNA software,the refined finite element model was developed to simulate the progressive collapse behavior of infilled RC frame. In the model,the continuous cap model was used to simulate the masonry and the contact algorithm was used to simulate the function of mortar. The accuracy of finite element model was validated by comparing the numerical results with Pushdown test results of four 1/4 scaled frames consisting of two bare frames and two infilled frames. The effects of thickness and masonry strength of the infilled walls on progressive collapse behavior of RC frames were analyzed through numerical simulation. The results show that amongst the considered column-loss scenarios,the infilled frames subjected to the loss of an interior column achieve the highest first peak load but the percentage of the enhancement due to infilled walls is the lowest. Conversely,the infilled frames subjected to the loss of a corner column scenario achieve the lowest first peak load but obtain the largest percentage of enhancement caused by infilled walls. It is found that the thickness of infilled walls has greater effect on first peak load than its strength.