Stress Analysis And Seismic Performance Study On Horizontal Interface Of Precast Shear Wall With Bolted Connection

The preformed fabricated components at the factory ensure its quality,so that only node connection and a little bit wet work are required on site,which reduces environmental pollution and shortens the construction period.Therefore,the prefabricated buildings are conducive to the industrialization of high-quality buildings.Bolted connection,a convenient dry connection form and sleeve grouting,a reliable reinforcement connection technology are two mature construction processes in China.So the new connection wall panel with bolt connection in the middle and sleeve grouting connection at the end-column longitudinal reinforcement has excellent promotion and application prospects.At present,there are few design references for the connection form wall panel,so it is necessary to study the stress analysis and seismic performance of the connection form wall panel.By using ABAQUS finite element analysis software,the static elastoplastic and quasi-static elastoplastic analysis numerical simulation analysis are carried out to the new connection wall panel in this paper.The effects of axial compression ratio,aspect ratio,bolt spacing,screw-to-hole clearance and interfacial friction coefficient on the seismic performance,failure mode and bolt shear performance of the prefabricated wallboard are studied,and optimize the level of each factor,the formula for fitting the bolt to the shear unevenness coefficient ? and the bolt shear ratio ? is proposed,and the bolt design method considering the shear unevenness of the bolt is proposed,multiple sets of prefabricated and cast-in-place contrast members are designed to analyze the type of failure and the force of bolt of prefabricated wallboard under different loading systems,and compare the bearing capacity,lateral stiffness and hysteretic energy of prefabricated wallboard and cast-in-place wallboard.And give design suggestions.The main conclusions are as follows:(1)The main factors affecting the peak load of the prefabricated wallboard in this connection form are the aspect ratio and axial compression ratio.The peak load increases linearly with the increase of the aspect ratio.the peak load increases more quickly as the axial pressure ratio increases from 0.1 to 0.3,and increases more slowly as the axial pressure ratio increases from 0.3 to 0.5.(2)The total shear force of the interface friction at the joint node is 67%~99%,and most of the members` exceed 80%.Therefore,the quality of the interface chisel roughness at the joint mode must be strictly controlled during the production of the member(3)The shearing force of the bolts in different positions is not equal.For the members with large bolt force,The shearing force of the bolt tends to increase first and then decrease as it moves away from the loading end.The main factor affecting the shear unevenness of the bolts is bolt spacing,aspect ratio,interfacial friction coefficient and screw-to-hole clearance,the unevenness coefficient ? decreases with the increase of bolt spacing,and increases with the increase of interfacial friction coefficient,and overall increases with the increase of screw-to-hole clearance.As the aspect ratio increases,it first increases and then decreases.It is recommended to reduce the unevenness of the bolt shear by appropriately increasing the bolt spacing and reducing screw-to-hole clearance.After the clearance between the screw and the hole wall is filled,The clearance should not exceed 1mm.When the screw-to-hole clearance is less than 1.5mm,the statistical formula of the shear unevenness coefficient ? is given.It is recommended that the aspect ratio be in the range of 0.83 to 1.25,the shear unevenness coefficient ? for these member is multiplied by 1.3.(4)For shear wall components with high axial compression ratios,the shear force of the bolts is small and the ductility of the components is poor.It is recommended that the axial compression ratio of the components should not exceed 0.6.(5)The main factors affecting the shear ratio ? of the bolt are the axial compression ratio,the interface friction coefficient,and the aspect ratio.Generally,? decreases with the increase of the axial compression ratio or the interface friction coefficient,and first increase and then decrease with the increase of the aspect ratio.The statistical formula of bolt shear ratio ? is given when the axial compression ratio is less than or equal to 0.3.Considering the influence of aspect ratio,it is recommended that the shear ratio ? is multiplied by 1.5 when the member has an aspect ratio of 0.83 or less and 1.25 or more.(6)A dark beam is arranged on the upper wall panel,and a steel backing plate is arranged under the nut,which can effectively prevent the punching damage and partial crushing of the component.The bolt failure does not precede the overall damage under the combined action of the pulling and shearing.The prefabricated wall panel of the connection form has small horizontal slip and good integrity.(7)The peak bearing capacity,lateral stiffness and energy consumption area of the prefabricated wallboard are reduced relative to the cast-in-place wallboard.However,the peak load capacity decreases by no more than 10%,and the reduction of the lateral stiffness is small,which can be neglected,and the energy consumption area decreases by no more than 5%.In consideration of the floor restraint and the good quality of the sleeve grout,the out-of-plane bending resistance of the prefabricated wall panel of the connection form is not lower than that of the cast-in-place component,and the out-of-plane bearing capacity,when the wall-floor node is connected with the corbel,is slightly higher than be equal to the cast-in-place's.In general,the prefabricated wall panel of this connection form has excellent seismic performance.(8)Under the action of monotonous loading and reversed cyclic loading in the plane,most bolts are always elastic during the loading process,indicating that there is still a large safety reserve at the node,which satisfies the requirement of “strong node”.The requirement for bolt loading under reciprocating loading is less than the bolt bearing capacity requirements under monotonous loading,According to the shear unevenness coefficient ? and the bolt shear ratio ? obtained from the monotonous loading to design the bolt,the shear design of the bolt is conservative.