钢绞线网-ECC加固RC柱小偏心受压承载力研究

Study on bearing capacity of RC columns strengthened by steel wire strand meshes-ECC under small eccentric compression

为解决小偏压钢筋混凝土(RC)柱的脆性破坏问题,将钢绞线网-工程水泥基复合材料(ECC)应用于RC柱加固,进行了该复合材料加固RC柱小偏心受压性能试验和理论研究,分析了加固方法、偏心距和纵向钢绞线配筋率等对加固RC柱小偏心受压性能的影响。结果表明:钢绞线网-ECC复合材料加固层可对受压区核心混凝土提供有效的约束,加固后RC柱的开裂荷载、峰值荷载及位移延性系数分别提高了100.0%~113.3%、99.8%~108.0%及75.9%~77.8%;相比仅ECC加固,钢绞线网-ECC复合材料加固效果更优;随着偏心距的增大,加固RC柱的开裂荷载和峰值荷载均降低,但其延性提高,而纵向钢绞线配筋率对其影响相对较小。在试验研究基础上,提出了钢绞线网-ECC复合材料加固RC小偏压柱的承载力计算式,计算结果与试验结果吻合良好,计算值与试验值的比值约为0.94。

In order to solve the problem of brittle damage of RC columns under small load eccentricity in practical engineering,steel wire strand(SWS)meshes-engineered cementitious composite(ECC)was applied to the strengthening of reinforced concrete(RC)columns,and the behavior of the strengthened RC columns under small eccentric compression was studied experimentally and theoretically.The influences of reinforcement method,eccentricity and longitudinal SWS reinforcement ratio on the small eccentric compressive performance of the strengthened RC columns were studied.The results indicate that the core concrete is effectively confined by the SWS meshes-ECC composite reinforcement layer,and the cracking load,peaking load and ductility of the strengthened RC columns are increased by 100.0%-113.3%,99.8%-108.0%and 75.9%-77.8%,respectively.RC columns strengthened by SWS meshes-ECC composites have obvious advantages over the column strengthened by ECC.With the increase of load eccentricity,the cracking load and peaking load decrease,but the ductility is improved,and the longitudinal SWS reinforcement ratio has a relatively small effect.Based on the test results,a formula was proposed to calculate the bearing capacity of RC columns strengthened by SWS meshes-ECC composites,and the calculation results agreed well with the test results with the ratio of the calculated value to the experimental value being about 0.94.