玄武岩纤维增强塑料筋混凝土梁受弯破坏形态有限元分析

Finite Element Analysis of Flexural Failure Mode of Concrete Beams Reinforced with BFRP Bars

设计并制作了3根新型的玄武岩纤维增强塑料筋(BFRP筋)增强混凝土梁,并对其进行三分点加载试验和有限元分析。结果表明,BFRP筋混凝土梁的受弯破坏形态不同于传统的钢筋混凝土梁,其破坏截面均位于加载点附近。梁内的销栓作用对BFRP筋的受力非常不利;较大的裂缝宽度不仅会影响到BFRP筋混凝土梁的正常使用,还会影响到梁的受弯破坏形态;BFRP筋突出的表面变形特征、较低的横向抗剪强度和弹性模量等对上述破坏形态的发生有着重要影响;加载点处BFRP筋混凝土较为严重的局部黏结破坏、较大的销栓作用、应力集中效应和较大的裂缝宽度等使BFRP筋处于复杂的不利受力状态,这是造成上述破坏形态的主要原因。

Concrete beams reinforced with plastics/basalt fiber composite （BFRP bars） were prepared and analyzed by three-point testing and finite element analysis. The flexural failure mode of the beam was different from traditional reinforced concrete beam in that the failure sections were all located near the load point. Finite elements analysis was carried out on the failure mode and the follows was considered as the main reasons： the mechanical behavior of BFRP bars was much adversely influenced by the dowel effect in the beam; the width of cracks affected the flexural failure mode; the failure mode was closely associated with the apparent surface deformation, the lower transverse shear carrying capacity, and the lower elastic modulus of BFRP bars; local bonding failure between BFRP bars and concrete, dowel effect, and stress concentration. The fourth constituted the main reasons of the failure mode.