侧向冲击下箱形钢管混凝土叠合柱动力响应试验研究

Experimental study on dynamic response of box concrete-encased CFST columns under lateral impact

为研究箱形钢管混凝土叠合柱抗冲击性能,利用自主研发的落锤式试验机进行了箱形叠合柱冲击试验,研究了边界条件、冲击高度和轴压比对冲击力时程、跨中位移、应变时程以及破坏形态的影响。试验结果表明:箱形叠合柱在冲击荷载作用下发生弹塑性破坏;随冲击高度的增加,冲击力时程曲线由两段式发展为三段式,柱破坏形态表现为外层混凝土开裂且剥落明显,但内部钢管混凝土跨中冲击部位钢管无局部屈曲;两端固定时的抗冲击性能较两端简支时增强;而轴力对其动力响应影响不显著。

To study the impact behavior of the box concrete-encased concrete-filled steel tubular( CFST) column,drop hammer test machine based on independent research and development was used to carry out impact experiments on the box composite columns,focusing on the effect of boundary conditions,impact height and axial compression ratio on the time history of impact force,mid-span displacement,time history of the strains and the failure pattern. The experimental results show that the failure of box concrete-encased CFST columns under impact loading belongs to elasto-plastic failure; with the increase of impact height,the time history curve of impact force is developed from two stages to three stages. The failure mode of the column shows that crack and spalling of the outer concrete is obvious,but the steel tube of internal CFST has no local buckling in the middle impact position; with the boundary conditions changing,the impact performance of specimens with fixed ends is better than that supported simply at both ends; and the axial compression has little influence on the dynamic response of the specimens.