斜向水平荷载作用下高强钢筋混凝土柱的抗震性能研究

Study on seismic performance of high strength reinforced concrete columns under oblique horizontal load

共设计了7组高强钢筋混凝土柱,考察了低周往复载荷作用下的加载方式、轴压比和约束条件对高强钢筋混凝土柱破坏形态、滞回曲线、骨架曲线和刚度退化曲线的影响。结果表明,无约束和有约束钢筋混凝土试件的滞回曲线都较为饱满,体现出良好的耗能能力;与无约束的试件相比,钢板网和碳纤维布约束试件的滞回曲线更加饱满,刚度退化变缓、耗能能力和承载力相对更大。在相同轴压比下,斜向加载试件B的屈服荷载(F_(y))、极限荷载(F_(u))、延性系数(Δ_(u)/Δ_(y))和刚度退化速率都相较正交加载试件A更低;随着轴压比从0.6增加至1.0,斜向加载作用下试件F的F_(y)和F_(u)增大、Δ_(u)/Δ_(y)减小,刚度退化速率加快;与无约束的试件D相比,有约束的试件E和试件F的Δ_(u)/Δ_(y)明显增大、刚度退化速率变小,而局部区格约束的试件G的Δ_(u)/Δ_(y)和刚度相较试件D减小、变形能力相对较差。钢板网和碳纤维布约束可以有效提升混凝土试件的承载力、耗能能力和变形能力,改善钢筋混凝土的抗震性能。

Seven groups of high-strength reinforced concrete columns are designed,the effects of loading mode,axial pressure ratio and constraint conditions on the failure form,hysteresis curve,skeleton curve and stiffness degradation curve of high-strength reinforced concrete columns under low cycle cyclic loading are investigated.The results show that the hysteresis curves of the unconstrained and restrained reinforced concrete specimens are full,which shows good energy consumption capacity;Compared with the unconstrained specimens,the hysteretic curves of the specimens restrained by steel mesh and carbon fiber cloth are fuller,the stiffness degradation is slow,the energy consumption capacity and bearing capacity are larger.Under the same axial compression ratio,the yield load(F_(y)),ultimate load(F_(u)),ductility coefficient of specimen B under oblique loading are lower than that of vertical loading specimen A;With the increase of axial pressure ratio from 0.6 to 1.0,F_(y) and F_(u) of specimen F increased under oblique loading,Δ_(u)/Δ_(y) decreases and the stiffness degradation rate is accelerated;Compared with the unconstrained specimen D,theΔ_(u)/Δ_(y) of constrained specimen E and F increases obviously,the rate of stiffness degradation decreases,while the stiffness degradation rate andΔ_(u)/Δ_(y) decreases and the deformation ability is relatively poor.Steel mesh and carbon fiber sheet can effectively improve the bearing capacity,energy dissipation capacity and deformation capacity of concrete specimens,and improve the seismic performance of reinforced concrete.