内嵌CFRP板加固已损伤RC梁抗弯性能的试验研究

Experimental study on the flexural behavior of damaged reinforced concrete beams strengthened with near-surface mounted CFRP laminates

通过对7根钢筋混凝土梁内嵌CFRP板加固的抗弯试验,探讨了CFRP板用量、损伤程度和加固方式对已损伤钢筋混凝土梁承载力、跨中挠度、破坏形态等方面的影响。试验结果表明,与未加固梁相比,已损伤的钢筋混凝土梁采用内嵌CFRP板法加固后,混凝土梁的极限承载力提高了34%～144%;CFRP板的用量对钢筋混凝土梁的抗弯性能影响较大,损伤程度对加固梁抗弯性能的影响不明显,内嵌CFRP板加固钢筋混凝土梁的抗弯性能优于外贴等量CFRP板的加固梁。基于混凝土结构加固理论,考虑开槽数量的影响,对内嵌CFRP板加固已损伤RC梁钢筋屈服前的短期刚度进行理论分析,并建立加固梁钢筋屈服前短期刚度的计算公式,其计算结果与试验实测值吻合较好。

Seven reinforced concrete beams strengthened with NSM CFRP were tested. The ultimate moment,deflection at mid span, failure mode of the test beams with the strengthening amount, damage degree and the way of strengthened were discussed. The experimental results showed that the load-bearlng capacity of the beams strengthened with NSM CFRP increases from 34% to 144% comparing with the beams which are not strengthened. The flexural behavior of the concrete beams were influenced by the strengthening amount, but the damage degree just has a little influence to the fiexural behavior of the concrete beams. Near-surface mounted CFRP strengthening beams has more flexural than bonded CFRP sheets strengthening beams. In consideration of the influence of the groove, the short-term rigidity were discussed for NSM CFRP laminates-strengthened damaged RC beams on the basis of the theory of concrete structure, and introduces a practical calculating method of short-term rigidity. The predicted results agree well with the measured values from the tests of the present.