分散型钢混凝土组合柱抗震性能试验研究

Experimental study on seismic performance of isolated steel reinforced concrete composite columns

为研究分散型钢混凝土组合柱(ISRCC)的抗震性能,分析组合柱中分散布置的型钢和混凝土之间的协同工作情况,对4个ISRCC柱进行偏心率为10%和15%的低周往复加载试验。与传统低周往复加载试验相比,试验中按预定路径同时施加竖向荷载和水平荷载。分析了ISRCC柱在低周往复荷载作用下的承载力、延性、破坏形态、裂缝分布和刚度退化等。试验结果表明:所有ISRCC柱均为小偏心压弯破坏,试件整体性较好;在偏心率15%以内,屈服荷载前各试件满足平截面假定,能够有效发挥型钢和混凝土的组合作用;ISRCC柱压弯承载力的试验值与ACI 318-2014、EN 1994-1-1和YB 9082—2006《钢骨混凝土结构技术规程》等规范中的承载力计算结果吻合较好,验证了现有规范中普通钢骨混凝土(SRC)柱压弯承载力的计算方法对偏心率15%以内的ISRCC柱的适用性;试件的极限位移角为1/88~1/65,满足我国规范对罕遇地震作用下框架-核心筒结构弹塑性层间位移角的要求,具有较好的变形能力。

To investigate the seismic performance of isolated steel reinforced concrete composite （ISRCC） columns, and to analyze the composite action between the concrete and steel sections, four ISRCC columns were tested under cyclic loading with eccentricity ratios of 10% and 15%, respectively. Compared to traditional quasi-static tests, the vertical load and horizontal load were applied together in accordance with the predetermined loading path. The bearing capacity, ductility, failure mode, crack distribution, and stiffness reduction were carefully examined. Test results indicate that all ISRCC columns fail in small eccentricity patterns, and the integrity is desirable. With eccentricity ratios less than 15%, the plane section assumptions can be validated for the tested specimens before yielding loads are reached. Actual flexural capacities of the ISRCC columns corresponds with the calculated values given by ACI 318- 2014, EN 1994-1-1 and YB 9082-2006, suggesting that current code provisions for designing SRC columns are applicable in predicting the capacity of ISRCC columns subjected to combined compression and bending with eccentricity ratio not greater than 15%. The specimens demonstrate good deformation capacities with ultimate drift ratios ranging from 1/88-1/65, which can meet the specified value given by the Chinese code for frame-core structures under high intensity earthquake.