表面内嵌FRP筋抗剪加固T形混凝土梁参数影响

为了研究不同参数对表面内嵌FRP筋加固梁抗剪性能的影响规律,对6根采用不同FRP筋类型、间距以及不同加固方式的FRP筋加固梁进行受剪性能试验.结果表明,该方法能够很好地改善加固梁的受剪性能,提高梁的极限承载力.未粘U箍和FRP筋间距小的加固梁更易发生剪切破坏.加固方式对加固梁跨中位移无明显影响,FRP筋类型和FRP筋间距对加固梁跨中位移影响显著.表面内嵌FRP筋不能提高试验梁的纯弯段开裂荷载,但能显著提高弯剪段开裂荷载.FRP筋类型、间距以及加固方式对加固梁的极限荷载影响显著.由于CFRP筋弹性模量高,故CFRP筋的应变小、利用率低;不粘贴U箍加固梁中FRP筋应变大于粘贴U箍加固梁;FRP筋间距越大,FRP筋的应变越大,利用率越高.

Parameter influence of T shaped concrete beams shear-strengthened with NSM FRP bars

In order to study the influence of different parameters on the shear properties of beams shear strengthened with near surface mounting （NSM） FRP bars, the shear property tests for 6 beams shear strengthened by FRP bars with different types, different spacing and different strengthening methods were performed. The results show that the proposed method can improve the shear properties of beams and enhance the ultimate bearing capacity. The beams with small spacing of FRP bars or without sticking U hoop are more likely to exhibit the shear failure, and the strengthening methods have no obvious effect on the mid span deflection, while the types and spacing of FRP bars significantly affect the mid span deflection. The NSM FRP bars can not enhance the cracking loads in the pure bending section of test beams, while can obviously increase the cracking loads in the bending shear section. The types, spacing and strengthening methods of FRP bars significantly affect the ultimate load of beams. Because the CFRP bars have higher elastic modulus, the strain of CFRP bars is small and its utilization rate is low. The strain of beam without sticking U hoop is higher than that with sticking U hoop. The bigger the spacing of FRP bars is, the greater the strain is and the higher the utilization rate is.