Investigation On Seismic Behavior Of The Superimposed Wall With Two Different Connections At The Foundation

Under the guidance of the national housing industry policy, the prefabricated shearwall structures have a very broad future prospects. The superimposed reinforcedconcrete (RC) wall studied in the paper is a kind of semi-precast RC wall which iscomposed of two precast panels and the cast-in-place core concrete. The truss barswhich are made up of one upper chord bar, two lower chord bars and the continuousinclined web bars are prefabricated with the two precast panels, aiming to connect theprecast and cast-in-place concrete together, and enhance shear resistance at theconnection interface. The past seismic tests in our research group have indicated that thehorizontal joint between precast panel and foundation is the weak point of the structuresunder earthquake. The elastic-plastic reaction of the structures were based on open andclose in the horizontal gap and rocking in the precast panel. This deformation modemade the vertical rebar across the horizontal gap deform largely even break. Theconcrete compression stress in the compression zone was relatively large, which makethe ductility decreased, so the aim of “emulation of cast-in-place” can not be reached.Based on those facts, this paper present two ways to improve the connecting region ofthe superimposed RC wall. One is the embedded foundation with the lap-rebar, the otheris the “strong connection” in the horizontal joint based on the capacity design principle,which is making the bending capacity of the horizontal joint section larger than nearbysection, so the plastic area could transform to the specify area. This paper present theseismic test and numerical analysis on the seismic behavior with the two differentconstructed ways.We has designed four test specimens, of which two is based on the use ofembedded composite plate shear wall specimens, two of laminated panels andfoundation with strong connections between the use of the specimen, and all wereloading low cyclic tested. The test results showed that: embedded base shear specimensof different longitudinal reinforcement and foundation wall dowels configuration,eventually emerged from the concave wall within the foundation pulled out of thedestruction, there is no basis for dowels and wall panels and foundation the contactsurface of the friction function together, the connecting portion of the wall of the forcebecomes weak link; the use of strong shear specimens were bent end connected to destroy the panel itself, on the basis of the insertion rib of adequate size, the can bemoved on the wall plastic hinge region "strong connection" purpose; specimens W-1horizontal force-displacement hysteretic curve is relatively plump spindle, while theother three specimens subjected to shear deformation, hysteresis loop inverse S-shaped;same kind of connection, the basic configuration of the high amount of Reinforcingspecimens have a higher capacity and energy dissipation capacity; displacementductility factor of four specimens is between3.36~6.81, the maximum vertexdisplacement angle is between1/68to1/46, with a certain deformation.Based on the experimental study, we also used the finite element softwareABAQUS right to force the process four specimens were nonlinear numericalsimulation, and analysis results were compared with experimental results. The resultsshowed that the horizontal load FEM acquired-vertex displacement curve skeletoncurves are in good agreement with the measured and analysis can more accuratelysimulate the failure modes4specimen, the finite element model has a certain reliability,can be used for follow-up Performance analysis of seismic shear laminate.