The Influence Of Infill Walls On The Progressive Collapse Resistance Of Precast Concrete Frames

Since London Ronan Point apartment collapse caused by gas explosion in 1968,progressive collapse of structures has attracted more and more attention in engineering practice and becomes a hotspot for study purpose.The research on the cast-in-place concrete frame is limited,and there is also a large gap in the research on the role of infill walls played in the progressive collapse scenario.Therefore,laboratory experiments and numerical analyses are presented in this dissertation to study the effect of infill walls on the progressive collapse resistance of PC frame.The content of this dissertation is as follows:(1)A two-layer,two-span prefabricated bare frame test was fabricated,and the mid column was subjected to quasi-static loading.The deformation,crack development and failure mode of the specimen during the process of progressive collapse were observed.The research shows that precast concrete frame can absorb more energy due to the existence of weak zone.Therefore,it is able to have a much higher capacity in centenary action stage than the cast-in-place concrete frame due to better deformation ability.(2)A frame with infill walls was fabricated,and the reinforcement details,section dimensions and loading approach were consistent with the bare frame specimen,expect that infill walls were constructed on the second story of the frame.The deformation,crack development and failure mode of the specimen during the process of progressive collapse were observed.The research shows that the infill wall is mainly used as the stressed member in the compressive arch action stage,which significantly improves the bearing capacity of the frame,and its bearing capacity peak is about 3.75 times that of the bare frame specimen.In the catenary effect stage,the infill wall is cracked but still has the constraint and support effect on the frame specimen.The peak bearing capacity of this stage is about 3.2 times that of the bare frame specimen.(3)The calculation method of the progressive collapse resistance of the precast concrete frame structure(both bare frame and frame with infill walls)was proposed,which will provide a reference for the design of the precast concrete frame structure against progressive collapse.