Seismic Performance Of Coupled Shear Wall Structure With Viscoelastic Replaceable Coupling Beams

It is a new development direction of the structural seismic technology to promote the earthquake resilience capacity of important high-rise buildings.As the first line to resist earthquakes,coupling beams in coupled shear wall structures are required to yield prior to the wall limbs,and plastic hinges are formed at the beam end caused by bending deformation to dissipate the input energy of earthquake.However,in the practical engineering,it is very difficult to avoid the brittle shear failure of coupling beams because of small span-depth ratio,and the cumulative plastic deformation and damage in coupling beams result in repair cost after earthquake.In order to improve the energy dissipation capacity and earthquake resilience capacity of coupling beams,the concept of viscoelastic replaceable coupling beams has been proposed.The coupling beams connecting wall limbs are split in the middle,and the new type of viscoelastic shear dampers with tooth profile steel plate are installed vertically between the ends of the two cantilevers with end plates and high strength bolts.Then these dampers are designed to dissipate seismic energy in frequent earthquake,moderate earthquake and rare earthquake,and can be replaced easily after the earthquake to resume the function of coupling beams as quickly as possible.The main research contents and results are as follows:(1)The proper position of the damper in coupling beams is addressed from the point of the mechanical characteristics and deformation of the coupling beams.Then the structural features and working mechanism of the new type of viscoelastic shear damper with tooth profile steel plate are proposed.The energy dissipation principle of viscoelastic shear damper is explored based on the dynamic property of viscoelastic material,and the control parameters of damper are suggested.(2)Based on finite element analysis program ABAQUS,a 12-story coupled shear wall model with conventional coupling beams is established.The modeling approach of shear wall and the constitutive relation of material are illustrated.The seismic responses of conventional coupled shear wall are obtained through dynamic elastic-plastic time history analysis.After that,the plastic damage development process of coupling beams and wall limbs is described through the damage nephogram.(3)Based on the conventional coupled shear wall model,another same 12-story coupled shear model with viscoelastic replaceable coupling beams is established.The viscoelastic dampers are simulated use spring and dashpot element.The dynamic responses of two models are compared through dynamic elastic-plastic time history analysis under different levels of ground motions.It is found that the base shear force,inter-story drift,acceleration and plastic damage of the model with viscoelastic replaceable coupling beams are both smaller than which of the conventional model.In other words,the coupled shear wall model with viscoelastic replaceable coupling beams has good damping effect.(4)Compared with the conventional coupled shear wall model,the seismic time-history analysis method is used to study the damping effect’s influence rules of the stiffness coefficient and the damping coefficient of viscoelastic dampers,and the optimum parameters were determined.It is found that the selection of stiffness coefficient and damping coefficient has a great influence on the damping effect of couple shear wall with viscoelastic replaceable coupling beams.Through reasonable selection of damper’s coefficient,the optimal damping effect can be achieved.The damping coefficient of viscoelastic damper has optimal values,and is more sensitive to the dynamic responses than stiffness coefficient.And the stiffness coefficient should be small when the optimal damping coefficient is determined and the stiffness of replaceable coupling beams is guaranteed.