Experimental study and analysis on flexural behavior of concrete filled double steel tubular composite columns
To study the flexural behavior of concrete filled double steel tubular(CFDST)composite columns,experimental and numerical studies and analysis of CFDST members under bending loads are carried out.Firstly,flexural test studies are conducted on seven composite columns(including five CFDST specimens,one conventional CFST specimen and one DCFST specimen),mainly considering the impact of concrete compressive strength,steel tube thickness,and diameter ratio on their flexural performance.The flexural failure modes,bending moment-curvature of CFDST,deflection curve of CFDST,and distribution of longitudinal strain on the section are analyzed.Secondly,nonlinear numerical simulation analysis is carried out for CFDST components.After verification based on experimental ultimate strength and failure mode,further impact analysis of main parameters is conducted.The results show that CFDST members exhibit better ductile behavior under bending loads,with the area of the outer tube having the greatest impact on the flexural capacity of the member,and the strength of the concrete having the smallest impact;Under bending loads,the ultimate strength and ductility of CFDST members have significantly improved compared to traditional concrete filled steel tubular members,but compared to DCFST members,the improvement in ultimate strength and ductility of CFDST members is very small.
double steel pipecomposite columnflexural performanceexperimental study
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