Dynamic Time History Analysis Of RC Frame Seismic Retrofitted By FRP

Fiber reinforced polymer (FRP) has many advantages in the field of reinforced concretestructures reinforcement, such as light weight, high strength, corrosion resistance, goodworkability etc. And it is widely used in the area of seismic retrofitting of reinforced concretestructure. There is no effect on the normal use and stiffness of the reinforced concretestructure retrofitted by FRP. The studies of reinforced concrete structure retrofitted by FRP athome and abroad are concentrated in single concrete members retrofitted by FRP at present,and lack of study on seismic performance of whole RC structure. Internal force, deformationand dynamic performance of elastic-plastic stage of structure can be obtained by dynamicelastic-plastic time-history analysis method. Compared with the response spectrum methodand static elastic-plastic time-history analysis method, the whole process of the structureseismic response can be described by dynamic elastic-plastic time-history analysis method. Inthis paper, dynamic time-history analysis method is adopted to study seismic performance ofthe whole RC frame structure retrofitted by FRP.Firstly, three1:2reduced-scale models of two-bay, two-story RC frame were made,retrofitted by CFRP and C/GFRP based on joints respectively, and then the low reversedcyclic loading tests were carried out. Secondly, the restoring force model of RC frame jointsretrofitted by FRP was built by analyzing test data. El-Centro wave, Taft wave and anartificial wave were selected, and then the dynamic time-history analysis for a6-story RCframe structure model was carried out by finite element software SAP2000. Finally, differentretrofitting schemes are proposed, which is only joints of the first floor were retrofitted byFRP, joints of structure from the first floor to the third floor were retrofitted by FRP,joints ofthe whole structure were retrofitted by FRP. Changes of FRP strengthening performance ofstructure from different retrofitting schemes were discussed.The research results demonstrated that ultimate bearing capacity, ductility, energydissipation capacity and seismic performance of reinforced concrete structure can beimproved efficiently by retrofitted by FRP based on joints. Seismic performance of RC frameretrofitted by CFRP and C/GFRP can be improved, and CFRP is better in seismic capacityimproving, C/GFRP is better in ductility improving. Ductility of RC frames retrofitted by three different retrofitting schemes can be improved, but RC frame retrofitted by retrofittingscheme1and retrofitting scheme2may lead to the problem of transfer of story weak. RCframe retrofitted by retrofitting scheme3was effective at changing the plastic hingemechanism from column-sway to beam-sway, which is in line with modern seismic designphilosophy of strong column and weak beam.So the method of RC frame retrofitted by FRPbased on joints is effective and feasible, and it can supply certain suggestions for actual civilengineering design.