轴压及轴拉作用下异形截面多腔钢管混凝土巨型柱抗震性能试验研究

Experimental study on seismic behavior of special-shaped CFT mega column with multiple cavities under axial compressive force and tensile force

结合超高层建筑巨型柱框架设计需要,进行了6个缩尺比为1∶25的六边六腔体钢管混凝土巨型柱模型试件低周反复荷载试验,试件设计时考虑了罕遇地震作用下巨型柱交替出现较大轴压力和较大轴拉力的工况,同时考虑了地震水平作用方向,沿截面长轴、短轴和45°方向加载。分析了6个试件的破坏特征、滞回特性、骨架曲线、承载力、延性、刚度退化、耗能和应变等。采用ABAQUS软件建立了有限元分析模型。研究表明:异形截面多腔钢管混凝土柱,沿截面长轴方向加载较其他方向加载试件的承载力平均提高了29.4%,耗能能力平均提高了6.8%;沿截面45°方向加载的试件,其抗震性能介于沿长轴与短轴加载的试件之间;轴拉下试件比轴压下试件承载力平均降低了8.4%,耗能能力平均降低了16.1%;6个试件的屈服位移角均值为1/82,最大弹塑性位移角均值为1/18,具有良好的变形能力;有限元分析模型较好地模拟了其受力过程。

Combined with the design requirement of mega column frame in super high rise buildings,six hexagonal CFT mega column specimens with six cavities were tested under low cyclic loading. In the test,the load case that compressive and tensile stresses alternately appeared under major earthquakes was considered; also the horizontal earthquake action direction was taken into account. The specimens were loaded along long axis direction,short axis direction and 45 degree direction,and the modeling scale was 1 /25. Failure patterns,hysteretic behavior,skeleton curves,bearing capacity,stiffness degradation,ductility,energy dissipating capacity and strain of the six specimens were analyzed. FEA model was established and simulation was conducted through ABAQUS software. Research shows that special-shaped CFT mega columns with multiple cavities have higher bearing capacity by 29. 4% averagely and stronger energy dissipating capacity by 6. 8% averagely in long axis direction than in other directions; the seismic behavior of the specimens loaded along the 45 degree direction is lower than that loaded along the long axis direction and higher than that loaded along the short axis direction; compared with the specimens under axial compressive force,the bearing capacity of the specimens under tensile force decreases by 8. 4% averagely,and the energy dissipating capacity decreases by 16. 1% averagely; the average value of yielding drift ratio of the six specimens is 1 /82 and that of maximum elasto-plastic drift ratio is 1 /18,indicating the deformation capacity is good; the FEA model can well simulate the loading process.