圆钢管再生混凝土柱抗震性能与影响因素分析

为了研究圆钢管再生混凝土柱的抗震性能,以再生粗骨料取代率、长细比、轴压比和含钢率为变化参数,设计10个圆钢管再生混凝土柱试件进行低周反复加载试验,观察了其破坏过程及形态,获取其荷载-位移滞回曲线。基于试验实测数据基础,深入分析了各变化参数对强度、刚度、位移延性和耗能系数等抗震性能指标的影响规律。研究结果表明:在破坏形态上,钢管再生混凝土柱与普通钢管混凝土柱相似,均表现为底部钢管鼓曲、混凝土被压碎。钢管再生混凝土柱的滞回曲线饱满,其形状从梭形发展到弓形。钢管再生混凝土柱的各项抗震性能指标能满足现有抗震规范要求,在地震区推广应用钢管再生混凝土柱可行。随着长细比的减小,试件耗能系数减小,而其他抗震性能指标增加。除刚度随轴压比的减小而减小外,其他抗震性能指标对现有的设计参数变化范围并不敏感。试件壁厚优势在强度、弹性阶段刚度和破坏点耗能系数等方面表现较为显著。

ANALYSIS ON ASEISMIC PERFORMANCE AND INFLUENCE FACTORS OF RECYCLED CONCRETE FILLED CIRCULAR STEEL-TUBE COLUMNS

In order to investigate the aseismic performance of recycled concrete filled circular steel-tube (RCFCST) columns, ten specimens were designed for a low cyclic reverse loading test. The four parameters such as recycled coarse aggregate replacement percentage, slender ratio, axial compression ratio and steel tube thickness were considered in the test. The failure process and modes of specimens were observed, and the hysteretic curves also obtained. Based on the test data, the effects of these parameters on the aseismic performance indexes such as displacement ductility, strength, stiffness and energy dissipation coefficients of specimens were discussed. The study results indicates that:the failure modes of RCFSST columns are similar to that of normal concrete filled circular steel-tube columns, and all of specimen's failure modes were local steel tube buckled and concrete crushed at the bottom of columns. The hysteretic curves are plump, whose shapes change from the early fusiformis to later arches. The aseismic performance index of a RCFSST column can meet the Chinese aseismic code requirements; and it can be used in the building of an anti-earthquake zone. With the decrease of slender ratio, only the energy dissipation coefficient is decreased, and the others aseismic performance indexes are increased. In this experimental vary range, the variation range of axial compression ratios is not sensitive to the aseismic performance of specimens, only the stiffness has a little decreased with the axial compression ratio's decreasing. With the steel tube thickness's increasing, the strength, elastic stiffness and energy dissipation coefficients of specimens are obvious improved.