CFRP板加固RC梁极限抗弯承载力试验

Experimental Study on Ultimate Flexural Bearing Capacity of RC Beam Strengthened with CFRP Panel

为了解CFRP板加固RC梁裂缝抑制及极限抗弯承载力影响效果,以孟加拉邦戈邦都大桥为背景,选取典型箱梁顶板结构单元,制作1∶1实体模型进行极限抗弯承载力试验,将试验结果与有限元和理论分析结果进行对比。结果表明:在RC梁发生极限破坏过程中CFRP板从中间向两端逐渐剥离并弹出,受压区混凝土未发生异样;未加固的RC梁平均裂缝宽度为2.75 mm,梁端最大位移为11.23 mm,平均极限抗弯承载力为90.8 kN·m,加固的RC梁平均裂缝宽度为0.61 mm,梁端最大位移为5.65 mm,平均极限抗弯承载力为159.6 kN·m,与未加固的RC梁相比,加固的RC梁极限抗弯承载力实际提高约76%;在RC梁发生极限破坏时,CFRP板约发挥了自身抗拉强度的23%;RC梁极限抗弯承载力加固前理论计算值小于有限元计算值,加固后理论计算值大于有限元计算值,加固前、后有限元计算值与实测值几乎相同。

To study the influence of crack suppression and ultimate flexural bearing capacity of strengthened concrete beams with CFRP panel,the typical box girder top plate structural element was selected based on the Bangabandhu Bridge in Bangladesh.The 1∶1 solid model was made for ultimate flexural bearing capacity test.The test result was compared with finite element and theoretical analysis results.The result indicates that during the ultimate failure process of RC beam,the CFRP panel gradually peels off and pops out from the middle to both ends,and there is no abnormality in compression zone concrete.The average crack width of unreinforced RC beam is 2.75 mm,the maximum displacement at beam end is 11.23 mm,and the average bending ultimate bearing capacity is 90.8 kN·m.The average crack width of reinforced RC beam is 0.61mm,the maximum displacement at beam end is 5.65 mm,and the average bending ultimate bearing capacity is 159.6 kN·m.Compared with the unreinforced RC beam,the actual bending ultimate bearing capacity of strengthened RC beam increases by about 76%.When RC beams undergo ultimate failure,the CFRP panel exerts approximately 23%of its own tensile strength.The theoretical calculation value of ultimate bending bearing capacity of RC beam before reinforcement is smaller than the finite element calculation value.The theoretical calculation value after reinforcement is larger than the finite element calculation value.The finite element calculation values before and after reinforcement are almost identical to the measured values.