| Reinforced concrete column-steel beam composite frame structure,referred to as"prefabricated RCS composite frame structure,is a structural system that conforms to the development trend of building industrialization and has broad application prospects.At present,the research on the progressive collapse resistance of the RCS composite frame structure(space frame)under accidental events(such as explosion and impact)has not been reported in the public literature.This paper is based on the static collapse test of the node substructure completed by the research group.The weakening design,fabrication and dismantling methods of the initial failure column are proposed.The prefabricated RCS space frame structure has been subjected to two progressive collapse resistance tests at different load levels.The displacement and strain are recorded through the dynamic data acquisition system,supplemented by high-speed the camera captures the deformation process of the structure.At the same time,the SAP2000 finite element software is used to conduct a numerical simulation analysis of the experiment.The main research contents and conclusions are as follows:(1)In the progressive collapse resistance test of the prefabricated RCS space frame structure,the traction force of the automobile is used to realize the instantaneous removal of the bottom A2 column.Compared with the blasting demolition method,this method has high safety,convenient operation,and no shock wave interference to the test data.A special study verifies the feasibility of this method.(2)In order to study the deformation of the remaining structure,the strain of the steel beam connecting plate,the vertical displacement of the failure point,the failure mode and the force transmission path of the remaining structure after the A2 column of the bottom layer of the prefabricated RCS composite frame structure is instantaneously removed,a 1/2-scale 2-story 1×2-spanprogressivecollapse test of assembled RCS space frame structure.The test results show that the prefabricated RCS composite frame structure designed in accordance with the current seismic code is instantaneously dismantled with a single side column at the bottom,the maximum angle of the steel beam connected to the failed column is much smaller than that given in the "code for design of anti-collapse of building structures" plastic corner limit.(3)In the case of the instantaneous failure of the failed column,by collecting the instantaneous displacement of the assembled RCS space frame structure and the strain of the steel beam,and recording the deformation of the members and the concrete cracks,the progressive collapse resistance of the RCS frame structure is revealed.As time goes by,the deformation of the structure in the later stage is also very important to resist the influence of progressive collapse performance.(4)The SAP2000 finite element software is used for nonlinear dynamic analysis,and the analysis results are compared with the test data to verify the validity of the finite element.Based on the time history curve of the axial force of each column,the load transfer path of the remaining structure is analyzed. |
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