Study On Seismic Performance Of SRC Columns-steel Beam Precast Joint

Compared with the traditional wet construction method,the fabricated structure has the advantages of short construction period,high production efficiency,good engineering quality,energy saving and environmental protection,etc.,meeting the requirements of sustainable development in today’s society.The unique advantages of the fabricated structure are undoubted,the reliability of the connection between the prefabricated components directly determines the overall performance and seismic performance of the structure.So,to the study the performance of connections between components under low cyclic reciprocating loads is the key to promote the development of assembled structures.Based on the research of fabricated structures and steel reinforced concrete structures at home and abroad,a new type of assembled SRC column-steel beam frame joint is proposed in this paper,and low cyclic loading tests are carried out.At the same time,it is simulated and analyzed by AQAQUS finite element software.The main research contents and conclusions are as follows:(1)Through the low-cycle reciprocating loading test of three 1/2 scaled new assembled SRC column-steel beam frame joints(one bolted joint PCBJ1,one welded joint PCBJ2,and one welded-bolted hybrid joint PCBJ3)the influence of different connection modes between steel beam and precast joints on the seismic behavior of the new type of joints is investigated,and the failure modes,hysteretic curves,skeleton curves,ductility,energy dissipation capacity,strength degradation and stiffness degradation of the joints are investigated(2)The ultimate bearing capacity of welded joints PCBJ2(both flange and web are welded)is the highest,and the ultimate bearing capacity of welded-bolted hybrid joint PCBJ3 is slightly larger than that of bolted joint PCBJ1.The hysteresis curve of the PCBJ1 has a slip phenomenon,showing obvious Z type,but the energy dissipation capacity is good.The hysteresis curve of PCBJ2 is slightly pinched and the hysteretic curve of PCBJ3 is quite full.The equivalent viscous damping coefficients of the three nodes are: 0.32,0.23,and 0.43,respectively,indicating that the energy dissipation capacity of welded-bolted hybrid joint PCBJ3 is the best,and that of the bolted joint PCBJ1 is the second.The displacement ductility coefficient of the 3 joints is between 4.03 and 12.19,and the overall plastic deformation ability is good.The ultimate failure of PCBJ1 is later than that of PCBJ2 and PCBJ3.When the maximum bearing capacity is reached,the strength degradation is faster.The strength degradation of PCBJ2 and PCBJ3 after reaching the maximum bearing capacity is relatively mild.The final failure of the three specimens is mainly caused by buckling and fracture damage at the beam end and joint.The precast core area module is basically intact,meeting the design requirements of "strong column,weak beam,strong node and weak component".The seismic behavior of the new joints can be further improved by improving the structural measures at the beam end and the joint.(3)Finite element analysis model of three joint specimens under low cyclic loading was established by using numerical simulation software ABAQUS.The failure mode,ultimate bearing capacity and stress distribution of each part of three joints are analyzed.Comparing the numerical simulation results with the experimental results,it is found that the simulated failure modes and ultimate bearing capacity are consistent with the experimental results,which verifies the correctness of the finite element model.