考虑周边结构约束影响的RC框架结构防连续倒塌性能研究

为了考察周边结构约束对钢筋混凝土（RC）框架结构防连续倒塌承载能力的影响，该文通过Qian K等进行的中柱移除的框架子结构拟静力试验，校核了论文中ABAQUS软件建立的框架子结构精细有限元分析模型的准确性。模拟所得的荷载位移曲线与试验曲线吻合良好，较好地模拟了中柱移除至子结构破坏的全过程。在成功进行模型校核的基础上，通过改变平面框架两侧边跨的约束情况，分析了两侧边跨约束对所研究子结构防连续倒塌承载力的影响；其次通过对比考虑楼板与不考虑楼板的单层空间结构的承载力，分析了楼板在结构防连续倒塌受力过程中对提高压拱阶段和悬链线阶段承载力的作用，讨论了楼板对连续倒塌各个受力阶段不同的影响；最后建立了多层空间框架结构模型，研究框架底层柱移除过程中结构的承载能力，分析发现楼层数的增加，成倍地提高框架结构承载力，并对连续倒塌各个受力阶段产生不同的影响。

PROGRESSIVE COLLAPSE RESISTANCE OF RC FRAME STRUCTURES CONSIDERING SURROUNDING STRUCTURAL CONSTRAINTS

This study investigated the effects of surrounding structural constraints on the bearing capacity of progressive collapse resistance of reinforced concrete(RC)frame structures.The accuracy of the sub-structural detailed finite element model established by the ABAQUS software was verified by the Qian K’s pseudo-static tests via the middle column removal of the sub-frame.The load-displacement curves obtained from the simulation were in good agreement with tested results,and the whole processes of the middle column removal until the sub-structure failure were well simulated.After the verification of the model,the effects of lateral span constraints on the plane sub-structural progressive collapse capacity were studied by varying the lateral span constraints.The effects of floor slab on improving the bearing capacity of arch and catenary stage were analyzed by comparing the capacity of a single-story space structure with or without considering the slab.Different effects of slab on various stages of progressive collapse were discussed.Multi-stories space structural models were established to study the structural bearing capacity during bottom column removal.The results show that increasing the number of stories multiplied the bearing capacity of the frame structure and exerted different effects on various stages of progressive collapse of RC frame structures.