Experimental study on seismic behavior of seismic-damaged RC frame composite strengthened with section steel
The seismic-damaged RC frames needs to be repaired quickly after the earthquake.The method of considering strengthening local structures and improving the seismic capacity of the overall structure was adopted,so as to restore or even improve the seismic capacity of the seismic-damaged frame.Combined with the stress characteristics and failure mode of the frame under the action of earthquake,the local strengthening of column adopts the angle steel and gusset plate.The whole frame is strengthened by thin-walled steel plate shear wall,oblique support,V-shaped buckling restrained brace.And the test of low cycle reciprocating loading was carried out on the specimen after reinforcement.The results show that after combined reinforcement,the seismic performance of the specimens is significantly improved.The"strong beam and weak column"failure mode of the original frame is transformed into the"strong node and weak member,strong column and weak beam"failure mode that meets the seismic requirements.When the specimen is damaged,the support and thin-walled steel plate are destroyed first,which can effectively avoid the premature failure of the main frame.After strengthening,the bearing capacity,initial stiffness,ductility and cumulative energy consumption of the specimens are significantly higher than those of the unreinforced specimens.The bearing capacity and stiffness of the specimens degrade slowly,and the final failure is caused by cumulative damage.The seismic performance and ductility of the specimen strengthened by V-shaped buckling restrained brace reinforcement is better than the specimens strengthened by other two combined strengthening methods because of its multiple energy dissipation capacity.Considering the seismic performance and failure mode of the specimen after reinforcement,it is suggested to use the method of V-shaped buckling restrained brace reinforcement.
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