#br#偏压荷载下钢管混凝土柱的抗扭性能试验研究

自重和水平地震作用将对曲线梁桥中墩梁固结的墩柱和拱桥钢管混凝土结构的主拱产生偏压和扭转复合效应。为研究钢管混凝土柱在偏压荷载作用下的抗扭性能，完成了8个不同截面形状钢管混凝土柱试件单调纯扭加载、往复纯扭加载和偏压-往复扭转加载拟静力试验。试验结果表明：钢管混凝土柱在往复扭转作用下的滞回曲线较为饱满，没有“捏拢”现象产生，试件的强度和刚度的损伤退化程度较低，具有较好的耗能能力。矮柱试件破坏现象较高柱试件更为明显，矮柱试件的屈服转角小于高柱，屈服扭矩与高柱相差不大，极限承载力大于高柱，极限转角小于高柱，耗能能力比高柱更好。偏压-往复扭转荷载作用下的方形截面试件刚度退化较为明显，偏压作用导致方钢管混凝土柱试件耗能能力降低。极限状态下，偏压作用改变了钢管的褶皱角度。

Experimental study on behavior of concrete filled steel tube columns under torsion and eccentric compression

Under the gravity and the horizontal earthquake load, the combined effect of eccentric compression load and torsion will be produced in the piers of curved girder bridges and the main arch of arch bridge. In order to study the torsion behavior of concrete filled steel tube columns subjected to the eccentric compression load, quasi-static tests were carried out on eight specimens of concrete filled steel tube columns subjected to static pure torsion, cyclic pure torsion and eccentric compression- cyclic torsion, respectively. The test results indicate that the hysteresis curve of concrete filled steel tube column subjected to cyclic torsion load is plump and no pinch phenomenon is found. The damage and degradation degree of the strength and stiffness of specimens is lower| and high energy dissipation capacity is achieved. The stiffness degradation of the square-section specimens subjected to eccentric compression-cyclic torsion load is more obvious. The eccentric compression load has led to the reduction of the energy dissipation capacity of the square concrete filled steel tube column. Under the ultimate state, the wave angle of steel tube is affected by the eccentric compression load.