Study On Reduction Factor Of Coupling Beams’ Stiffness In Shear Wall Structure

Coupling beam is one of the most important members in shear wall structure whichis designed with small span, large section and stiffness connected with shear wall.Under horizontal earthquake, shear wall begins to bend first, then the coupling beamrotates due to the difference of vertical deformation. The moment and shear force ofcoupling beam happen in such way. In practical structures, coupling beams tend to bebrittle failure because of over reinforcement and large shear force. Stiffness of couplingbeam behaves as constraint of shear wall, therefore it has large influence on themechanics behavior and failure mode of shear wall structure.This thesis uses sap2000to reduce the stiffness of the coupling beams in thecoupled shear wall, calculate the internal force of the members and make the coupledshear wall reinforced according to the calculation. Then the elastic-plastic analysis onthe different reinforced shear wall proceeds under small earthquake; For further study,this thesis uses the finite software ABAQUS to simulate the shear wall structure withdifferent stiffness of coupling beams which is loaded ground motion in single direction,conduct the elastic-plastic analysis in order to study the influence that stiffness ofcoupling beams have on shear wall structure.Main conclusions as follows:①Based on previous research, this thesis summarize the factors affect thereduction factor of coupling beams’ stiffness mainly including span-depth ratio ofcoupling beams, height of the structure, seismic intensity, loading conditions. Thedetermination of reduction factor should consider several factors comprehensively.②Reducing the elastic stiffness of coupling beams in shear wall structure canrelieve the problem of over-reinforcement and over-shear-force in some degree undersmall earthquake. However, coupling beams damage seriously under large and superlarge earthquake.③The stiffness of coupling beams in shear wall structure should balance damageand ductile energy dissipation. Coupling beams with small stiffness tend to damageunder small earthquake.④It is suggested that choosing element model should match the concrete situation.The calculation work of simulating concrete with beam element and shell element,barssimulated with combination method is much smaller compared with those concrete simulated with solid element and bars modeled by the separation method while thestress and strain results can be output separately by the former simulation method.