高温后钢管混凝土短柱落锤动态冲击试验研究

摘要

采用落锤冲击实验机进行了高温作用后钢管混凝土短柱抗冲击性能试验研究,通过试验研究试件所经历的最高温度、升降温全过程中轴压力水平、冲击速度、冲击能量和含钢率等参数对高温后钢管混凝土抗冲击性能的影响.试验量测了钢管混凝土应变、冲击力和压缩变形时程曲线,试验结果表明,试件所经历的最高温度、冲击速度、冲击能量和含钢率均对高温作用后钢管混凝土的动态力学性能有显著的影响,而升降温全过程中轴压力水平的影响较小.试件的轴向和径向残余变形随着试件所经历的最高温度、冲击能量、轴压比的增大而增大,随着含钢率的增大而减小.高温后钢管混凝土在冲击作用下产生了较大的压缩变形,延性有所下降,但仍能够保持很好的完整性,说明钢管混凝土在高温作用后有良好的抗冲击能力.%A drop weight setup was used to experimentally study the impact resistance of concrete-filled steel tube (CFT) after exposures to high temperature. The influences of high-temperature, impact velocity, impact energy, steel ratio and axial load level on the impact resistance of CFT under fire exposure were discussed. The stress-strain relation, the force and compressive deformation versus time history relations of the tested specimens were recorded to analyze the impact behaviors of CFT columns after exposure to high temperature. The test results show that the influences of high-temperature, impact velocity, impact energy and steel ratio have remarkable effects on dynamic behaviors of CFT columns, but the influences of axial load level is not noticeable. The compressive deformations and residual deformations would increase obviously with the increase of high-temperature, impact velocity and axial load level, but decrease with the increase of steel ratio. Although the CFT specimens after exposure to high temperature suffer remarkable compressive deformations and the ductility of CFT decreases, the composite columns still remain in good integrity. The test results show that CFT after exposure to high temperature is of excellent impact-resistance.