高强箍筋约束高强混凝土短柱抗震性能试验研究

Experimental study on seismic behavior of high-strength concrete short columns confined with high-strength stirrups

通过6个复合箍筋约束高强混凝土短柱在高轴压比下的低周往复水平加载试验,研究了其破坏过程、破坏形态、抗剪性能以及各个受力阶段箍筋应力的变化,并通过与普通强度箍筋混凝土短柱试件对比,分析了箍筋强度、箍筋间距、配箍率等因素对短柱受剪承载力、滞回特性、耗能能力及延性性能的影响。结果表明:配置高强箍筋对短柱受剪承载力的影响不显著,但明显提高和改善了其耗能能力和延性性能;高强箍筋混凝土短柱具有较普通箍筋混凝土短柱的滞回曲线"饱满",循环次数多,刚度衰减慢等特点;在配箍率等条件相同的情况下,高强箍筋混凝土短柱的延性和耗能能力均明显优于普通箍筋混凝土短柱;达到峰值水平荷载时,普通箍筋达到或接近于屈服,而高强箍筋仍具有较高的应力储备,当达到极限水平荷载时,部分高强箍筋接近于屈服。

A total of 6 high-strength concrete short columns confined with composite stirrups were tested under cyclic lateral loading and constant axial loading. The failure process,failure modes,shear behavior and stirrups stress level of the specimens were studied. Furthermore,by comparing with specimens confined with normal strength stirrups,the influences of the stirrup strength,stirrup spacing and stirrup ratio on shear bearing capacity,hysteretic characteristics,energy dissipation and ductility performance of columns were analyzed. Research results show that the impact of highstrength stirrups on shear bearing capacity of short columns was not obvious,but it may significantly improve the energy dissipation capacity and ductility performance of short columns. Compared with those columns confined with normal strength stirrups,the columns confined with high-strength stirrups are characterized with more plump hysteretic curves,slower stiffness degradation and more cycles. With the same stirrup ratio,the ductility performance and energy dissipation capacity of columns confined with high-strength stirrups are significantly better than those columns confined with normal strength stirrups. When the peak horizontal load is reached,the normal strength stirrups may almost yield,while the high-strength stirrups may still have enough reserves in stress. When the ultimate load is reached,only a part of high strength stirrups are close to yielding.