高强混凝土多重复合芯柱抗震性能试验研究

Experimental study on seismic behavior of high-strength concrete columns reinforced with multiple composite central reinforcement

以某地铁站房工程为背景,设计并制作了8个高强混凝土多重复合芯柱试件,选取轴压比、箍筋形式、配箍率为变量,进行低周反复荷载试验研究,分析其破坏过程及形态,系统研究该类多重复合芯柱的滞回性能、骨架曲线、变形能力、刚度退化和耗能能力,应用Park-Ang损伤模型对该类新型混凝土柱的损伤演化规律进行分析,基于性能化设计理念给出高强混凝土多重复合芯柱的损伤指数与破坏程度的对应关系。研究结果表明:高强混凝土多重复合芯柱发生弯剪破坏和剪切破坏;随轴压比增大,峰值荷载增大,但变形性能和延性降低,承载力衰减和刚度退化加快,耗能能力明显减弱;随配箍率增大,芯柱试件滞回环面积增大,延性提高,承载力衰减和刚度退化减缓,耗能能力显著增强;配箍形式对芯柱试件耗能能力影响较大,其中试件C-SC-100和C-DC-100的滞回性能、变形性能、耗能能力明显改善,表明外螺旋内圆和内外双圆箍筋的配箍方式增强了核心区混凝土的约束,从而提高该类芯柱的抗震性能;层间位移角1/50时,各试件损伤指数D为0.17~0.35,均未发生严重破坏,表明该类多重复合芯柱抗震性能较好,复合芯柱最终破坏时的层间位移角为1/29~1/21,且损伤指数均大于1。

Eight high-strength concrete columns reinforced with multiple composite central reinforcement were designed and fabricated to conduct research about the construction of a subway station project.Taking the axial compression ratio,stirrup form and stirrup ratio as the main variables,the low-cyclic reversed load tests were carried out to analyze the failure process and failure modes,and the hysteretic behavior,skeleton curve,deformation capacity,stiffness degradation and energy dissipation capacity were systematically studied.The Park-Ang damage model was utilized to analyze the damage evolution law of the columns.Based on the philosophy of performance-based design,the relationships between damage index and damage degree of the column specimens were given.The results showed that the column specimens experienced bending-shear failure and shear failure.With the increase of axial compression ratio,the peak loads increased significantly,but the deformation performance,the ductility,the bearing capacity,the stiffness and the energy dissipation capacity decreased.With the increase of stirrup ratio,the hysteretic loop area of the columns,the ductility and the energy dissipation capacity increased,while the peak load,the bearing capacity and the stiffness degeneration decreased.The change of stirrup type can significantly influence the energy dissipation capacity of the specimens.The hysteretic behavior,deformation performance and energy dissipation capacity of specimen C-DC-100 and C-SC-100 were better,which indicated that these stirrup forms could effectively restrain the concrete in the core area,so the seismic behavior of the columns was improved.The damage indices of all specimens were between 0.17 and 0.35 at the story drift of about 1/50,and no serious damage was observed,which proved the good seismic behavior of high-strength concrete columns reinforced with multiple composite central reinforcement.The columns were destroyed at story drifts from 1/29 to 1/21,and the damage indices of the columns were greater than 1.0.