Study On Seismic Behavior Of Cast-in-place Concrete Hollow Slab-shear Wall Joint

Compared with the traditional rib beam floor,the large-span cast-in-place concrete hollow floor with wide flat hidden beam has the advantages of significantly reducing the floor height,cost,energy saving and environmental protection,and is widely used in high-rise structures.Compared with frame-core tube structure,due to the cooperative work of wide flat hidden beam and surrounding slab,wide flat hidden beam shear wall has different deformation and energy dissipation capacity from frame beam shear wall under earthquake.For this reason,based on the seismic design idea of "strong wall and weak slab",this paper makes theoretical and Experimental Research on the hidden beam shear wall joint in the cast-in-place concrete hollow floor system in terms of stiffness and bearing capacity,and mainly achieves the following results:(1)Based on the failure criterion of "strong wall weak slab",the recommended formula for the minimum thickness of the wall limb in the joint is put forward.The results of numerical analysis of three finite element models with different wall limb thickness show that with the increase of wall limb thickness,the failure mode of cast-in-place concrete hollow slab shear wall joint changes from out of plane failure of wall limb to end failure of hollow slab in turn,which shows that the recommended formula of minimum wall limb thickness can ensure the formation of yield mechanism of "strong wall weak slab",which can be used in practical engineering design.(2)Based on the failure criterion of "strong wall and weak slab",a 1 / 3 scale test model of five cast-in-place concrete hollow floor shear wall joints,such as shear wall hidden beams and columns,is constructed respectively,and cyclic reciprocating load test is carried out.The test results show that when the minimum thickness of shear wall limb is satisfied,the failure mode of "strong wall and weak slab" can be realized,and it has good ductility and seismic energy dissipation Power.At the same time,aiming at the hollow floor hidden beam shear wall joint,the paper puts forward the structural measures of setting shear wall hidden beam in full length and setting hidden column in the width range of hollow floor hidden beam to ensure that the joint has better seismic bearing capacity and deformation capacity.(3)Based on the results of cyclic reciprocating load test and numerical analysis,the equivalent width and height of hidden beams and columns in the shear wall are determined,and the calculation formula of out of plane bearing capacity of shear wall based on the torsion resistance of hidden beams and bending resistance of hidden columns is put forward;the mechanism of the participation of hollow slabs around the hidden beams is studied,and the calculation method of the bearing capacity of the wide flat hidden beam is established considering the local force of the hollow floor..According to the design principle of "strong wall and weak slab",the seismic increasing coefficient of shear wall is introduced,which is γ = 1.2.The design method of seismic bearing capacity of hidden beam shear wall joint of hollow floor is established,which is characterized by bending moment failure of beam end.