Study On Seismic Behavior Of The Base-isolated RC Shear-wall Frame Structure

Base-isolation as the most widely applied seismic isolation technology,it increases the structure’s flexibility and provides additional damping by configuring isolation layer between foundation of the building and the upper structure,and achieves the effect of reducing the seismic action of the structure.This paper aims to investigate and compare the mechanical behaviors of reinforced concrete frame-shear wall structure with and without base-isolation system through experimental study,numerical study and the theoretical study.The main studies of this thesis are as follows:(1)By conducting cyclic lateral loading tests on two concrete frame-shear wall specimens(non-isolated and isolated member),the mechanical properties such as crack developing sequence,failure mode,hysteretic curve,deformability and energy dissipation were studied and compared.For the isolated specimen,when the horizontal displacement of the bearing in the isolation layer reached 100%-200% shear strain,the internal force distribution and the plastic deformation development of the base-isolated concrete frame-shear wall structure were analyzed,the effect of the isolation bearing’s shear deformation on the vertical deformation of frame-bottom bearing and wall-bottom bearing was obtained,and the effect of uneven sedimentation of bearings on the transfer beam was explored.(2)By using the finite element analysis software ABAQUS,a refined model was proposed to simulate the isolated concrete frame-shear wall specimen.By comparing with test results of skeleton curve,plastic damage,and bearing deformation,etc.,the model could validate the test results.Using this numerical analysis model,the bearing deformation at the bottom of the isolation layer and the stress development of the conversion beam were analyzed.(3)Based on experimental and numerical study,according to the simplified mechanical model of the wall-conversion beam of isolated structure,the calculation formula of strength capacity of the transfer beam was given and the shear strains of the isolation layer were obtained when the transfer beam achieved yielding.The comparison with experimental results shows that this simplified model was reasonable,which could provide reference for the future design of transfer beam in base-isolated frame-shear wall structure.