Study On Seismic B Ehavior Of Superimposed Shear Wall With Concealed Steel Plate Bracings And Flexible Connection At The Vertical Joint

As a semi-assembled structure,the precast superimposed concrete shear wall（PSCSW）can not only shorten the construction period,reduce the impact of on-site construction on the environment,increase the mechanization rate,but also save labor costs.However,due to the requirement of its transportation,the PSCSW needs to be assembled on site,and whose joints at the assembly place have an important influence on the seismic performance of the PSCSW.For ensuring the reliability of the joints of the PSCSW,and at the same time keep consistent goal with the assembly component,this paper proposes a new dry connection method of bolt connection,and then the bolt connection is applied to the vertical joint of PSCSW.In the paper,the flexible connection with concealed steel plate bracings（CSPB）is taken as the research object to research the seismic behavior of wall with the flexible connection by bolt connection through quasi-static cyclic loading test and finite element（FE）simulation.The main research contents and results are as follows:（1）Through quasi-static cyclic loading test,the failure mode,hysteresis performance,skeleton curve,bearing capacity（BC）,displacement ductility,stiffness degradation and energy dissipation capacity of the superimposed shear wall with CSPB and flexible connection at the vertical joint were obtained.And the test results show that dry connection method of bolt connection placed at the vertical joint had no damage during the whole loading process,exhibting a good connection performance.Furthermore,it could be found that the new dry connection method of bolt connection applied to the vertical joint of the superimposed concrete shear wall could obtain similar lateral BC,peak displacement and ultimate displacement with the cast-in-situ concrete shear wall compared to the cast-in-situ concrete shear wall,which had higher lateral BC but slightly worse energy consumption than those of the wet connection method applied to the vertical joint of the superimposed concrete shear wall.（2）The FE simulation of the superimposed shear wall with CSPB and flexible connection at the vertical joint was conducted by ABAQUS,and then the simulation results were compared with the test results.It was found that the simulation results were in good agreement with the test results,which verified the rationality of the FE model in this paper.（3）On the basis of the FE model of the superimposed shear wall with CSPB and flexible connection at the vertical joint,the influence of some cricial parameters on the seismic performance of the wall were further studied.The results showed that increasing the axial compression ratio within a certain range can significantly increase the horizontal BC of the wall,but reduced its ductility.Also,increasing the thickness and strength of the CSPB can improve the horizontal BC of the wall,but it was recommended that the grade of the CSPB should not exceed Q345.Besides,increasing the thickness and strength of the connecting steel plate can improve the horizontal BC of the wall as well,and increasing the thickness of the connecting steel plate would improve the BC of the wall significantly.