FRP网格-工程用水泥基复合材料复合材料加固钢筋混凝土梁挠度

Deflection of reinforced concrete beams strengthened with FRP grid-engineered cementitious composite matrix composite

为研究纤维增强复合材料(FRP)网格-工程用水泥基复合材料(ECC)复合加固方式对钢筋混凝土梁的挠度影响,对10根钢筋混凝土梁进行抗弯性能试验,分析了各试验变量对FRP网格-ECC复合材料加固钢筋混凝土梁挠度的影响,并推导加固梁挠度计算模型。试验结果表明:FRP网格-ECC复合加固方式能显著提升试验梁极限承载力和抗弯刚度,其中加固梁极限承载力提升27.9%~67.4%、跨中挠度降低30.7%~43.7%,且发生延性特征明显的适筋破坏;FRP网格对加固梁抗弯性能影响较大,网格厚度与加固效果成正比;ECC加固层的厚度、配合比和界面处理方式对加固梁抗弯性能影响较小,其中磨砂处理对加固层界面粘结性能提高较好;基于规范推导了加固梁挠度计算模型,其计算值与试验值吻合较好,该模型为FRP网格-ECC复合材料加固梁挠度计算提供一定的参考。

To study the effect of fiber reinforced plastic(FRP)grid-engineered cementitious composite(ECC)matrix strengthened method on the deflection of reinforced concrete(RC)beams,flexural performance test was carried out on 10 RC beams.Each test variable which does effect on the deflection of RC beams strengthened with FRP grid-ECC matrix composite was analyzed,and a model for calculating the deflection of reinforced beams was derived.The test results show that the FRP grid-ECC matrix strengthened method can significantly improve the ultimate bearing capacity and flexural stiffness of the test beams,in which the ultimate load carrying capacity of the reinforced beam increases from 27.9%to 67.4%,the mid-span deflection decreases from 30.7%to 43.7%,and the reinforced beams occur suitable reinforcement damage with obvious ductile characteristics.The FRP grid has a strong influence on flexural performance of reinforced beams,and its grid thickness is proportional to the strengthening effection.The thickness,matching ratio and interface treatment method of ECC reinforcement layer have little effect on the flexural performance of the reinforced beam,and the sanding treatment improves the interface bonding performance of the reinforcement layer better than other interface treatment methods.The deflection calculation model of reinforced beams is derived based on the specification,and its calculating values agree well with the testing values,so the model is a reference for the deflection calculation of RC beams strengthened with FRP grid-ECC matrix composite.