Research On The Resistance Of Progressive Collapse For Reinforced Concrete Frame Structure Strengthened With Steel Plates

Without the design of progressive collapse,there is a risk of progressive collapse for a large number of the existing buildings.Once progressive collapse are caused to happened,it will inevitably result in heavy casualties and severe economic damage.Therefore,the mechanical response of buildings against progressive collapse is studied,and it has become an urgent problem to improve the integrity and security of existing buildings by reasonable strengthening methods.The method of the reinforcement with bonded steel plate is applicable to improve the progressive collapse behavior of RC frame structure,with the advantages of high and strong efficiency,economic,short construction time and so on.The 6-layer numerical analysis model of reinforced concrete frame structure was established by ANSYS,then the risk assessment was performed by linear static method and nonlinear static method for the numerical analysis model in different failure conditions.The results show: the reinforced concrete frame structure would collapse progressively under the corner column failure.To further analyze the evaluation results in different failure conditions,four RC beam-column sub-structures were established by ANSYS.The nonlinear computation was carried out.By studying the resistance-displacement curve,resistance-time curve,the development of cracks,plastic hinge and the strength of the concrete and steel,the resistance mechanism for different beam-column sub-structures was obtained.Based on risk assessment results and resistance mechanism for the structure,three different reinforcing methods were put forward for the corner column failure.Reinforcement of RC beam-column substructure finite element model were established by ANSYS,and the nonlinear computation was carried out.By comparing the indexes of bearing capacity,ductility and crack,the resistance mechanism for different beam-column sub-structures with bonded steel plate was studied.The better method of the reinforcement with bonded steel plate scheme was obtained.The better bonding steel reinforcement scheme is selected,the strengthened RC frame structure model is established,and then the nonlinear computation was carried out.The results show: The strengthened RC frame structure would not progressively collapse,so the validity of the reinforcement scheme was further confirmed.Based on the finite element analysis in this paper,some suggestion for strengthening RC frame structure against progressive collapse were put forward.