考虑全填充墙作用的钢筋混凝土框架抗连续倒塌性能分析

To investigate the progressive collapse performance and bearing capacity of reinforced concrete (RC) frames with full-height infill walls subjected to a middle column removal scenario, macro-based numerical models were built based on previous test results and finite element (FE) program OpenSees, and used to conduct systematic analyses. In the macro-FE models, beams and columns were modeled using force-based fiber beam elements, and the infill walls were converted into equivalent struts and modeled using truss elements. The macro-models of infill walls involved the width and the number of the equivalent struts, as well as the corresponding material properties. Through thorough comparisons of many strut models, eventually, the way to convert infill walls into struts suitable for progressive collapse analysis was suggested. After the validation, the numerical models were used to demonstrate the load transfer mechanisms of the RC and infilled frame and to investigate the effects of frame stories and compressive strength of infill wall on the progressive collapse performance. The results indicate that infill walls and surrounding frame members form a truss mechanism to transfer vertical load, in which the strut contributed by the infill is the most critical. The peak structural resistance decreases with the decreasing of the compressive strength of masonry units. Finally, taking the stiffness ratio of the infill wall to the surrounding frame as the main parameter, a model is proposed to quickly evaluate the progressive collapse capacity of regular RC frames with full-height infill walls.