The Mechanical Behaviors Of New Steel-concrete Composite Structure

At home and abroad, the mechanical behaviors of the steel-concrete composite structure has done a great deal of research, but new steel-concrete composite structure, such as stirrups confinement concrete-filled square steel tubular(SCFT) and concrete-filled round-ended steel tubular(CRT) has seldom done research.This paper uses the finite element method and experiment study to analyze the mechanical behaviors of new steel-concrete composite structure. The main research contents listed as follows:(1) Present an experimental study of3concrete-filled square steel tubular (CFT) stub columns,2concrete-filled square stiffened steel tubular stub columns and6loop or spiral SCFT stub columns concentrically loaded in compression to failure. The influences of ultimate bearing capacity and ductility of these stub columns under stiffeners or different types of loop or spiral stirrups confinement were discussed.ABAQUS was used to establish the3D finite element model and to analyze the behavior of CFT and SCFT stub columns under axially compression. Two practical calculation formulas for the ultimate bearing capacity of CFT and SCFT stub columns were proposed.(2) Present an experimental study of4concrete-filled circular steel tubular stub columns and7CRT stub columns concentrically loaded in compression to failure. ABAQUS was used to establish the3D finite element model and to analyze the behavior of CRT stub columns and concrete-filled elliptical hollow section steel tubular (CET) under axially compression. A practical calculation formula for the bearing capacity the stub columns was proposed.(3) Both3D finite element model and elasto-plastic method were applied to analyze the load-deformation curve of steel reinforced concrete-filled circular steel (SR-CFST) stub columns. Based on the limit equilibrium method, A formula of ultimate bearing capacity for the axially loaded SR-CFST stub columns was proposed.(4) ABAQUS was used to analyze the constitutive relationship of the steel-concrete composite columns, connections and frames.Then, the seismic constitutive relationship of SCFT columns,connections and frames under different axial compression ratio, stirrup yield strength and the ratio of the stirrup steel were analyzed.