圆台形大空心率中空夹层钢管混凝土构件压扭性能研究OA北大核心CSTPCD

Tapered concrete-filled double-skin steel tubular members with a large hollow ratio(TLHR-CFDST)are a new variation of concrete-filled double-skin steel tubular members(CFDST).In engineering practice,TLHR-CFDST members are often subjected to combined compression-torsional loads.To study the coupled compression-torsion behavior of TLHR-CFDST members,6 specimens were designed and tested.The examined parameters in the test included the tapered angle,the hollow ratio and the axial compressive ratio.A finite element(FE)model was established to analyse the working mechanism and parameter effects of the member.The results show that the member mainly fails in the upper sections.The torsional stiffness and the torsional capacity of the member decrease when the tapered angle increases whilst the effect of the hollow ratio on the torsional capacity is not significant.The member has good ductility when the axial compressive ratio is less than 0.4,whereas the torque-torsional angle curve shows a considerable descending branch when the axial compressive ratio exceeds 0.4.Under the confinement of the steel tube,concrete can continue to resist the torsional load after cracking.The compression-torsion capacity correlations of TLHR-CFDST members are similar under different parameters.A design method was proposed to predict the ultimate capacity of the TLHR-CFDST member under combined compression-torsional loads.The predicted bearing capacities agree well with the tested data and the simulated results.