复合材料加固混凝土梁斜截面承载力的研究

外粘贴纤维复合材料(FRP)加固钢筋混凝土梁的斜截面承载力与加固方式、FRP材料、FRP-混凝土界面应力和混凝土梁的原始参数有关。针对汶川地震中大量的斜截面破坏问题,分析了不同的加固方式、加固材料、配箍率、剪跨比和混凝土强度等参数对加固效果的影响。结果表明:FRP综合加固后混凝土梁斜截面承载力和变形能力明显提高,混凝土裂缝扩展延缓,加固效果明显;其中剪跨比和混凝土强度对加固后梁的挠度影响较大,而配筋率对加固后梁的承载力和变形能力均有较大影响,但对承载力影响最明显。同时对外贴FRP加固后混凝土梁的斜截面承载力进行理论分析,通过与已有的理论计算公式相比较,理论计算结果与试验结果符合较好。

Research on Bearing Capacity of Concrete Beams Shear Reinforced by FRP Sheets

The load carrying capacity of reinforced concrete(RC) beams externally bonded with fibre reinforced polymer(FRP) depends on the reinforcing arrangement,FRP material,FRP-concrete bonding interface stress and initial parameters of the RC beams.To repair the structures damaged in Wenchuan Earthquake,the RC beams with different reinforcing arrangement,stirrup ratio,shear span ratio and concrete strength were investigated.The results showed that externally bonded FRP sheets can increase the shear resistance and ductility greatly,arrest concrete crack extension,and the rigidity of strengthened beams also increased greatly.The deformability of the beam strengthened can be improved by increasing the beam height and the concrete strength.The load carrying capacity and deformability of the beam strengthened can be enhanced by increasing the stirrup ratio,but the load carrying capacity increases more obvious.Finally,the oblique cross section’s bearing capacity of the FRP reinforced concrete beams was analyzed,and the theoretical and practical formula for calculating was established.The results showed that the theoretical calculation is in accord with the experimental data.