碳纤维布加固混凝土梁的界面剪应力分析

Interface Shear Stress Analysis of Concrete Beam Strengthened with CFRP

基于弹性理论,放弃了平截面假定,并以碳纤维布加固混凝土梁的破坏形态为计算模型,通过界面分析建立了微分方程,推导了在集中力荷载作用下碳纤维布和混凝土梁之间的界面剪应力计算公式。该计算公式具有一定的通用性,通过改变特解的形式可适用于其它形式的荷载。对公式分析表明,界面剪应力在梁跨中部位附近较小,但在靠近锚固端部迅速增大并达到最大值,它不但与碳纤维布和混凝土的材料性质有关,而且还与碳纤维布的贴厚度、宽度、锚固端弯矩等因素有关。减小碳纤维的厚度和刚度或增加粘贴厚度,可以减小界面剪应力最大值。通过算例,计算了不同参数情况下界面剪应力的最大值,并与有限元法计算结果相比较,相对误差在18%以内,具有较好的计算精度。

Based on elastic theory, abandoned the plane-section assumption and the failure model of concrete beams strengthened with CFRP, the differential equations are established by analysis of the interface, and the formulae about the concrete beams strengthened with CFRP under concentrated load are deduced. This formula has some versatility, and can apply to other forms of load by changing the particular solution in the form. Results show that the interfacial shear stress at mid-span are smaller, but increase rapidly near the end of the anchor and reached the maximum. The interfacial shear stress not only relate to the material property of CFRP and concrete, but also to the thickness, width and bending moment at the anchor end etc.. Reducing CFRP stiffness and thickness or increasing viscose layer thickness, these can reduce the maximum interface shear stress at the end of anchoring. By a numerical example, different parameters are calculated to take the case of the maximum interfacial shear stress, and the results were compared with the finite element method, the relative error is less than 18%. It has a better accuracy.