【摘要】 设置斜放方钢管能够有效提高方钢管混凝土柱的轴压承载能力和延性性能，由此，进一步对内斜外正方钢管复合约束混凝土柱在低周反复荷载作用下的抗震性能进行试验研究。研究参数有轴压比、剪跨比、内方钢管边长和壁厚，设计并制作9个柱试件。试验获取了试件的滞回曲线、骨架曲线和特征点参数，分析并比较了不同影响参数对试件的破坏形态、水平承载力、层间位移角、位移延性系数、刚度退化和耗能性能的影响规律。结果表明：试件的破坏形态均为柱脚处环形鼓曲破坏，滞回曲线经历3个变化过程，由枣核形逐渐变化到饱满的梭形。相比方钢管混凝土柱，雷达图显示的组合柱综合抗震性能更优，平均水平承载力至少提高了6.83%,特征点的层间位移角能够满足实际工程应用的要求。剪跨比为4.75的试件刚度在缓慢退化阶段相差不大。研究参数对等效黏滞阻尼系数的影响在上升段更明显。增大轴压比，试件具有更大的峰值荷载，滞回曲线更饱满，等效黏滞阻尼系数和累积耗能均增大。减小剪跨比，试件的峰值荷载增大，等效黏滞阻尼系数和累积耗能减小。内方钢管边长或壁厚对试件峰值荷载的影响不明显；但内方钢管边长对骨架曲线影响更大，而等效黏滞阻尼系数对内方钢管壁厚的变化更敏感。刚度退化系数、等效黏滞阻尼系数以及循环耗能与相对位移的数值模拟结果与试验值吻合良好。更多还原

【Abstract】 The built-in oblique square steel tube can effectively improve the bearing capacity and ductility of concrete-filled square steel tube(CFSST) columns. Therefore, the seismic performance of double-skin concrete-filled steel tube(CFST) columns with inner-inclined and outer-square columns constraints under low cyclic load has been further studied. The influencing parameters include axial compression ratio, shear-span ratio, side length and thickness of inner square steel tube. A total of 9 column specimens were designed and manufactured. The hysteretic curves, skeleton curves and characteristic point parameters of the specimens were obtained, and the effects of different influencing parameters on the failure process, horizontal bearing capacity, interstory displacement angle, displacement ductility coefficient, stiffness degradation and energy dissipation performance of the specimens were analyzed and compared. The results show that the failure modes of the specimens were continuous buckling failure at the foot of the column, and the hysteretic curve has undergone three changes, its spindle shape grew from slender to full gradually. Compared with the CFSST column, the double-skin CFST columns with inner-inclined and outer-square composite constraints that shown in the radar map has better comprehensive seismic performance, the horizontal bearing capacity was increased by 6.83%, and the interstrory displacement angle on characteristic point could meet the requirement of practical engineering applications. At the stage of slow stiffness degradation, the stiffness of specimens with shear-span ratio of 4.75 had little difference. The influence parameters had obvious effect on equivalent viscous damping coefficient at the rising stage. A larger axial compression ratio made larger peak load, plumper hysteresis curve, and higher equivalent viscous damping coefficient and cumulative cyclic energy consumption. With the increased of shear-span ratio, the specimen had smaller peak load, but higher equivalent viscous damping coefficient and cumulative cyclic energy consumption. The effect of increasing the side length or thickness of inner square steel tube on peak load was not obvious. The change of inner steel tube side length had a significant effect on skeleton curve, and the equivalent viscous damping coefficient was more sensitive to the change of inner steel tube thickness. The numerical simulation results of relationships between stiffness degradation coefficient and relative displacement, equivalent viscous damping coefficient and relative displacement, cyclic energy consumption and relative displacement all were in good agreement with experimental results.更多还原