Analytical Investigation Of Seismic Performance Of Hybrid FRP-Concrete-Steel Double-Skin Tubular Members

Fiber Reinforced Polymer(FRP)-concrete-steel double-skin tubular column(FSDSTC)is a new type of composite member,which is composed of an outer FRP tube,an inner steel tube and concrete filled between the two parts.The FSDSTC has the advantages of light weight,short construction period,good corrosion resistance,high ductility and seismic performance.At present,the existing research work on FSDSTCs mainly forcus on the axial and eccentric compressive behavior,very limit studies were conducted on seismic performance,especially using numerical simulation method.In order to address the gap of existing stuies on the seismic performance of FSDSTCs,this thesis presents an analysis work on the seismic performance of FSDSTCs subject monotonic and cyclic lateral load.On the basis of analytical investigation,the lateral load-displacement hysteretic model for FSDSTCs is developed.The main research contents are as follows:(1)Based on OpenSees software,the full-process nonlinear analysis of FSDSTCs under monotonic lateral load is conducted.The simulation results agree well with existing test results,which demonstrate the correctness of modeling approach and accuracy of simulation results.On this basis,the multi-parameter expansion analysis was carried out.The influence of axial compression ratio,shear span ratio,thickness of FRP tube and steel tube and hollow ratio on the monotonic lateral load-displacement cuvre of FSDSTCs was investigated and obtained.(2)Analytical simulation analysis of lateral load-displacement hysteretic behavior of FSDSTCs was carried out based on OpenSees.The numerical calculation results agree well with existing experimental data.On the basis of verified finite element modeling and hysteretic analysis approach of FSDSTCs,the variation of the influence parameters of axial compression ratio,shear span ratio,FRP tube thickness,steel tube thickness and hollow ratio on the seismic hysteretic performance of FSDSTCs is investigated and obtained.(3)Pushover analysis was conducted considering 2250 parametric aconditions.The influence of axial compression ratio,shear span raio,concrete strength,thickness of FRP tube and steel tube on the characteristic parameters of the load-displacement skeleton curves of FSDSTCs was obtained.On this basis,the three-line lateral load-displacement hysteretic model for FSDSTCs is proposed.The comparison with test results shows that the calculation results of the proposed hysteretic model are in good agreement with the experimental results.The proposed lateral load-displacement hysteretic model for FSDSTCs can be used for seismic design and analysis and providing theoretical basis and technical support for the practice application.