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由各种纤维复合材料(FRP)加固混凝土梁端斜裂缝诱发的“端头FRP-混凝土界面剥离”是一种常见破坏模式,而用有限元方法对有多条裂缝的整根加固梁进行分析难度很大。该文提出一个简单的以加固梁端第1条斜裂缝为边界的“梁段”空间非线性有限元计算模型,并用圣维南原理和数值分析证实其合理性和可靠性。进而对此模型进行参数分析,探讨FRP拉应力、FRP层数、FRP-混凝土粘结滑移本构关系和加固梁端第1条斜裂缝到支座的距离诸因素对剥离应力的影响。经比较,模型计算结果与既有实验数据吻合较好。
The “tip FRP-concrete interface peeling-off” induced by diagonal cracks in concrete beams strengthened with various kinds of fiber composite materials (FRP) is a common failure mode. However, the finite element method Analysis is very difficult. In this paper, a simple nonlinear finite element model of “Beam Section” with the 1st oblique crack at the reinforced beam end is proposed. Its rationality and reliability are verified by Saint Venant principle and numerical analysis. Then the parameters of the model are analyzed. The influences of the tensile stress of FRP, the number of FRP layers, the bond-slip constitutive relation of FRP-concrete and the distance between the first crack and the abutment on the reinforced beam end are discussed. After comparison, the calculated results agree well with the existing experimental data.