Tests Of GFRP-concrete-steel Double Skin Tubular Short Columns Under Axial Compression

GFRP-concrete-steel double skin tubular columns is a new type of member which is made of outer GFRP tube,inner steel tube and reinforced concrete between them.It has the advantages of corrosion resistance,good seismic performance,light weight,large bending stiffness,and has a good engineering application prospects.In recent years,scholars at home and abroad is in the research of its mechanical properties,basically is still in the initial stage.This paper analyzes the performance of the GFRP-concrete-steel double skin tubular columns under axial loads by the test analysis and the finite element numerical simulation.Experimental research part designed 27 GFRP-concrete-steel double skin tubular columns(CHS inner and CHS outer)and 27 GFRP-concrete-steel double skin tubular columns(SHS inner and CHS outer)with different hollow radio,diameter-thick ratio of GFRP and the concrete strength grade.Through the axial compression test,observed the test phenomenon,the failure pattern,the load-strain curves,the load-displacement curves,and analyzed the influence with different parameters.The experimental results showed that with the increase of hollow ratio,the bearing capacity of the specimen is reduced;with the increase of diameter-thick ratio of GFRP,the bearing capacity of the specimen is reduced;with the increase of concrete strength grade,the bearing capacity of the specimen is improvement.Numerical analysis use the finite element software ABAQUS.Analysis results coincides well with the experiment results.Then,research the mechanical behaviors of GFRP-concrete-steel double skin tubular columns under the different influence parameters include hollow radio,diameter-thick ratio of GFRP and the concrete strength grade.Numerical simulation to simulate the test phenomenon,the failure pattern,the load-displacement curves.The results showed that the simulation results and experimental results are identical with each other.In addition,the parameters were analyzed with the verified finite element model,the main research parameters are hollow radio,diameter-thick ratio of GFRP and the concrete strength grade,results showed that with the increase of hollow ratio,the bearing capacity of thespecimen is reduced;with the increase of diameter-thick ratio of GFRP,the bearing capacity of the specimen is reduced;with the increase of concrete strength grade,the bearing capacity of the specimen is improvement.Finally,on the basis of the parameter analysis,the bearing capacity formulas of the two types of GFRP-concrete-steel double skin tubular columns were put forward.