Seismic Performance Analysis Of SRC Frame Structure Under Bidirectional Earthquake

Steel reinforced concrete(SRC)structure,as a common structural system in modern building construction,has the advantages of high bearing capacity,light weight and good seismic performance,etc.Compared with the traditional reinforced concrete structure,SRC structure shows better performance advantages and development prospects.At present,scholars at home and abroad mainly focus on the research of its seismic performance for unidirectional seismic action,although the consideration of bidirectional seismic action has been studied,but from the depth and breadth of research content still need to be carried out more in-depth research.Based on the SeismoStruct platform,the fiber model is used to simulate the existing experiments and verify the applicability of the fiber model.Based on this model,the effects of axial compression ratio,steel ratio and steel strength on the seismic performance of H-shaped SRC column under bidirectional horizontal loading are investigated,and compared with those under unidirectional horizontal loading in the x-direction.The results show that the column bearing capacity increases first and then decreases with the increase of axial compression ratio,while the energy consumption and ductility gradually decrease with the increase of axial compression ratio.And the bearing capacity,energy dissipation and ductility of the column increase obviously with the increase of the steel ratio.The bearing capacity,energy dissipation and ductility are all improved slightly with the increase of steel strength.In addition,the bearing capacity,energy dissipation and ductility of the SRC column under bidirectional loading are lower than those under unidirectional horizontal loading.Three L-shaped SRC frame structures with three-layer,nine-layer and fifteen-layer are designed,and the dynamic elastic-plastic time history analysis of them under the unidirectional and bidirectional seismic action is analyzed by Midas/Gen.The results show that the maximum inter-story displacement angle of the structure in X direction is1.0-1.3 times of that in unidirectional seismic action,and meets the requirement of 1/50 of the limit of inter story displacement angle specified in the seismic code,the maximum story shear force is 1.1-1.3 times of that in unidirectional seismic action,the maximum peak displacement is 1.0-1.3 times of that in unidirectional seismic action,the maximum angle column axial force is 1.5-1.9 times of that in unidirectional seismicaction,the maximum angle column bending moment is 1.0-1.4 times of that in unidirectional seismic action.It can be seen from the above analysis that the influence of bidirectional seismic action on the axial force of corner column is the most significant,followed by the others.Compared with unidirectional seismic action,the influence of bidirectional seismic action on L-shaped SRC frame structure is significant.When carrying out seismic design,it is unreasonable to consider only unidirectional seismic action,and the influence of bidirectional seismic action must be considered.Under the same seismic wave action,the time history curve of the structure under the unidirectional and bidirectional seismic action has the same change trend.Under the same peak acceleration and duration,but the different frequency spectrum characteristics of the seismic wave action,the seismic response of the structure is very different.