Bidirectional Seismic Performance Of Infilled RC Frames

As one of the commonly used building structure forms in China and the world,the masonry infilled reinforced concrete(RC)frame has the advantages of flexible space arrangement,simple construction procedure and low cost.Because the direction of actual seismic action is random,it is not safe to consider the response in-plane or out-of-plane of the filled wall alone,and the failure mechanism of the interaction in-plane and out-of-plane of the filled wall should be scientifically recognized.Through pseudo-static test,five single-span single-layer masonry infilled RC frame structures are loaded in combination in-plane and out-of-plane,and the seismic performance in-plane and out-of-plane of solid filled wall,open hole filled wall and GFRP reinforced masonry infilled are studied respectively.Based on the finite element analysis software,the masonry infilled RC frame structure is modeled separately,and the influencing factors of the stability of the filled wall are analyzed by parameters.The contents of the study are as follows:(1)Low cycle reciprocating loading is carried out in the test plane,and the failure modes of the masonry infilled RC frame structure at different loading stages are discussed.According to the test results,the seismic performance indexes such as hysteretic curve,skeleton line,strength,stiffness and energy dissipation capacity of each specimen are analyzed.GFRP reinforced masonry infilled the 1% inter-layer displacement angle,the lateral load increases 42.8% compared with the general solid fill wall,which increases the energy dissipation and shock absorption capacity of the structure.(2)Out-of-plane stability of infilled walls is one of the key research contents of this paper.In this paper,purely out-of-plane loading specimens are used as a reference group,and the effects of in-plane masonry-filled walls on out-of-plane stability are compared.The results show that the infill wall can increase the bearing capacity outside the plane to a certain extent when the in-plane load is maintained.After the infill wall has no load damage in the plane,the infill wall will reduce the out-of-plane strength and stiffness,and there is a strong coupling between the in-plane and out-plane.The out-of-plane seismic performance of the infill wall after opening is greatly weakened,and the use of GFRP reinforcement can effectively improve the stability of the infill wall.(3)Using ABAQUS software to simulate the seismic performance inside and outside the plane of the filled wall RC frame structure,the validity and reliability of the finite element model are verified by the error analysis of the failure mode,strength and stiffness of the partial test and the finite element simulation in this paper and other literatures.The sensitivity analysis and evaluation are carried out for a variety of influence parameters in the verification process,which can be used for infilled wall RC.The finite element simulation of frame structure provides some reference.(4)Based on the validated finite element model,the effects of infill wall heightthickness ratio,aspect ratio and masonry compressive strength on the in-plane and out-plane seismic performance of infill wall RC frame structure were studied.The study found that the larger the height-thickness ratio,the easier the damage in the plane will cause the strength of the infill wall to decrease outside the plane.When the height-to-width ratio of the infill wall is increased or decreased,the in-plane damage has a small effect on the outof-plane strength and stiffness of the infill wall.Increasing the compressive strength of the masonry can increase the bearing capacity outside the plane of the infill wall,but has less influence on the interaction between the plane and the plane.In addition,based on the above calculation results,the seismic performance of the infill wall in and out of the plane was reasonably analyzed,and the changes in strength and stiffness reduction coefficients of the infill wall were predicted.