Research On Mechanical Properties Of Slender Concrete-filled GFRP Tube Columns

With the continuous progress of science and technology,and the need of society's development,the engineering environment which involved by construction projects is becoming more complex.Especially with the increase of coastal and ocean engineering projects,the composite structure of FRP is more and more widely used for its good corrosion resistance,including GFRP-confined concrete columns.So it is quite necessary to carry out experimental research and theoretical analysis extensively and deeply on such columns' mechanical properties in the fields of building structures.At present,most of the research on the concrete-filled GFRP tube columns is aimed at the combination of short columns,while there are a lot of large slenderness ratio columns in practical engineering.In order to enrich the research achievements in the field of slender columns,in this paper,the axial compression and low cyclic loading test of GFRP tube composite columns are carried out at first.The results show that this kind of columns has good axial compression and seismic performance.Andthe change of GFRP fiber winding angle has an effect on the mechanical properties of slender columns.On the basis of experiment,the axial compression and seismic performance of combined slender columns under different operating conditions are studied by using the finite element analysis software ABAQUS.Draw the results about the influence of the change of slenderness ratio,axial compression ratio and GFRP fiber winding angle on the axial load displacement curve,hysteresis curve and skeleton curve which reflect the mechanical properties of this kind of columns.Meanwhile,the calculation formula of axial compression bearing capacity of GFRP tube-concrete composite spender columns is presented based on the experimental and numerical analysis results,and highlight the determination method of stability coefficient and lateral force enhancement factor.Then verify the rationality of the formula.In addition,establish a simplified model of hysteresis curve of the combined spender columns through the analysis of the finite element simulation results.Finally,regress and derive the main parameter of the simplified model,obtain a basic calculation method.