Research On Seismic Behavior Of Fabricated Concrete Shearwall Structure With Rebars Spliced By Squeezed Couplers

The characteristic of on-site assembly construction determines that the connection form of assembly nodes is the core technology of fabricated concrete shear walls.Among the existing multiple connection methods,squeezed-coupler connection is a cost-effective connection method.In this paper,an fabricated concrete shear wall with a back pouring area,where the vertical steel bars in the wall are connected by squeezed couplers and the sleeves are arranged in a single row in a plum blossom shape is proposed.In this paper,the seismic performance of 2 cast-in-situ shear walls and 7 fabricated concrete shear walls with rebars spliced by squeezed couplers are studied,using shear-span ratio,axial compression ratio,and concealed column structure as research parameters.The main research work and results are as follows:(1)The cyclic loading experimental studies which were carried out with 2 cast-in-place specimens and 1 corresponding fabricated specimen with the same parameters show that both of their failure modes are bending and compression failure that steel bars yield in tension area and the concrete crush in compression area while horizontal bars has not yet yielded.The hysteretic curves of both are bow-shaped,and the paths of hysteretic loops at all levels are similar and the fullness is the same,indicating that it is feasible for the connection form to be applied to the vertical connection of fabricated concrete shear walls,and the fabricated specimens can reach the bearing capacity and energy dissipation capacity of cast-in-place specimens,as well as seismic performance.(2)The cyclic loading experimental studies on 7 prefabricated specimens with changes in shear-span ratio,axial compression ratio and hidden column structure show that the shear-span ratio ? has an important influence on the failure mode of the specimen.In this paper,the specimen with ? = 0.9,1.06,1.13 are flexural-shear failure,the larger ? is,the smaller the shear effect is,and the specimen with ? > 1.13 is bending failure.The effect of axial compression ratio on the specimen is that the axial compression ratio increases,the bearing capacity increases slightly while the ductility decreases obviously.The hysteretic curves of all specimens are bow-shaped,with or without slightly pinch.(3)The finite element pushover analysis is carried out by using the concrete constitutive model recommended by the Code for Design of concrete structures GB50010-2002 and that of Mander confined concrete.The results show that the simulation results of Mander confined concrete constitutive model are in good agreement with the experimental study results.On this basis,the finite element parametric analysis is carried out,and the results indicates that the shear effect of the oblique section of the shear wall under horizontal load can be obviously reduced when the shear-span ratio is greater than 1.7,which makes the specimen more inclined to bending failure,and when the axial compression ratio is about 0.62,the displacemental angle corresponding to the peak load is the largest,and when the axial compression ratio is either greater or less than this value,the peak displacement angle decreases.Properly adjusting the size of the hidden column can not only improve the horizontal bearing capacity of the specimen,but also improve the ductility of the specimen.