FRP抗弯加固空心板非线性有限元分析及参数研究

Nonlinear FE Modeling and Parametric Analysis on Flexural Strengthened Hollowed Core Slab with FRP

以FRP抗弯加固预应力空心板为研究对象,考虑钢筋、混凝土材料本构的非线性以及FRP与混凝土间的界面剥离,进行加固后结构承载能力的非线性有限元分析。分析表明加固后结构的承载力和延性都得到了较大幅度的提高,数值分析结果明显大于按现有规范公式得到的计算值。此外,从混凝土强度、FRP的轴向刚度、FRP材料用量和二次受力4个方面对FRP加固空心板效果进行了参数分析。结果表明:混凝土强度、FRP的轴向刚度对加固效果影响较大;FRP材料用量存在最优用量,超过最优用量后,加固后结构的受力性能并无明显改观;当结构以钢筋屈服和混凝土压碎为破坏形式时,二次受力对钢筋和FRP的应变影响较大,但对整体结构的极限承载力影响较小。

In the analysis of the flexural strengthened hollowed core slab with Fiber Reinforced Polymer （ FRP）, with the nonlinear of the concrete and steel constitutive model, the beating-capacity of strengthened structure was simulated by using nonlinear finite element analysis based on the behaviors of the bonded interface between FRP and concrete. The results indi- cate that the beating-capacity and ductility of the strengthened beam have a substantial increase and the simulation results are obvious larger than these calculated by the current specifications. And four factors, including the strength of the con- crete, axial stiffness of the FRP, the usage of the FRP and secondary load, were used to investigate the strengthening effect of FRP. It shows that the concrete strength and axial stiffness of the FRP has a great influence on the strengthening effect. The usage of the FRP has an optimal value, and when the FRP usage exceeds this optimal value, the mechanical perform- ance of the structure has no obvious improvement after strengthening. When the main damage form of the structure are the rebar yield and concrete crush, the secondary force has large influence on the strain of the rebar and FRP, but smaller influ- ence on the ultimate load-bearing capacity of the overall structure.