Study On Seismic Performance Of Self--Resilient Coupling Beam

This paper introduced the concept and principle of “replaceable coupling beam”(R-CB),and summarized the progress of research and application of various R-CBs including different energy-dissipated ways by metallic yielding,friction,viscoelastic behavior,etc.The concept of “self-resilient structure” was proposed to break through the traditional thought of restoring structural function by replacing structural components,and to acquire self-resilient function without replacement after the earthquake.In the end,a self-resilient coupling beam(SR-CB)was designed to solve essential seismic problems existed in shear wall structures,while the basic construction,principles,characteristics of SR-CB were also elaborated.14 groups of lead viscoelastic coupling beam damper(LVCBD)models are established and analyzed through finite element software called ABAQUS to study the influence of the LVCBD's mechanical performance caused by different parameters,including the distance between lead core's center and outside edge of the composited viscoelastic layer,lead core diameter,thickness ratio of shear plate to constrained plate,thickness ratio of thin plate to viscoelastic layer in the composited viscoelastic layer,shear modulus and steel type,which provides the suggested values of the design parameters.Suggested that the lead core should be symmetrically arranged on the outside of the composited viscoelastic layer and the distance should be 1~1.5 times of lead core diameter;The lead core diameter should be determine by requirements of the LVCBD's yield capacity;The thickness ratio of shear plate to constrained plate is 1.00~2.00,and the thickness of shear plate should be 0.8 times of the thickness of the composited viscoelastic layer;The thickness ratio of thin plate to viscoelastic layer is 0.4~0.8 and the smaller value should be taken priority;Viscoelastic material with low hardness is recommended to achieve a better energy dissipation ability of the LVCBD;Q345 steel is recommended to guarantee the normal work of LVCBD and exert a stable energy dissipation capacity.TheLVCBD effectively works under complex loading condition in engineering application,which including shear force,axial force,bending moment or their combined loads.Thus,the performance of LVCBD under complex loading condition had been studied by using numerical simulation method,which the loading cases include axial pressure-shear force,axial tensionshear force,positive bending-shear force,negative bending-shear force,axial pressure-positive bending-shear force,axial pressure-negative bending-shear force,axial tension-positive bending-shear force,axial tension-negative bending-shear force.The results indicated that,the axial force has small influence on the mechanics performance of LVCBD and the bending moment mainly affects the LVCBD's yield displacement and yield force;Under the single shearing condition and complex loading condition,the hysteresis curves of LVCBD coincide well,the maximum damping force and equivalent viscous damping ratio are basically identical,and the complex loading cases have little impact on the energy dissipation and stress distribution of LVCBD compared with the single shearing case.The reasonable stiffness ratio between the energy dissipation beam(the LVCBD)and the non-energy dissipation beam(the RC beam)is the key to ensure a good performance of the SR-CB.10 groups of SR-CB models with different stiffness are established and numerical simulation analysis is carried out to investigate the influence of the SR-CB's mechanical performance.Moreover,the coordinated deformation mechanism,the mechanical mechanism and the energy dissipation principle are revealed,and the reasonable value of the stiffness ratio proposed is from 5 to 15.From perspective of engineering application,the theoretical calculation formulas of SRCB are derived,and the connection requirements are also given.The reasonableness and feasibility of the theoretical calculation formula are verified by comparing the results of the theoretical calculation and the finite element analysis.Finally,the fundamental design process of the SR-CB is summarized,and the stiffness equivalent design method of the SR-CB is proposed based on the demand of the bearing capacity.Due to the story drifts of a high-rise frame-corewall structure in high seismic intensity region is beyond the limit,the SR-CB was adopted to control structural vibration in the seismic energy dissipating design.Elastic time history analysis under frequent earthquake and inelastic time-history analysis under rare earthquake respectively by using ETABS and Perform-3D were conducted on the primary structure and damped structure equipped with LVCBDs to investigate the structural seismic response and energy-dissipated capacity of LVCBD.The research results indicate that the LVCBD can be applied in damping design of frame-corewall structure to enhance seismic performance of the whole structure,mitigate or avoid plastic failures of the main structural components,and play first seismic line function,which can protect the safety of main structure in the earthquake.