短纤维对FRP加固混凝土梁承载能力的影响

基于连续损伤理论,考虑胶层的剪切效应,建立了FRP加固修补混凝土结构的高阶剪切弯曲与面内变形耦合的非线性有限元分析模型.在FRP加固修补中,考虑到绝大多数破坏形式是在FRP附近混凝土表层到钢筋保护层之间发生剥离,很少在碳纤维布与混凝土的粘结界面或纤维布与粘结层的界面发生破坏,为了提高FRP加固混凝土结构界面区和整体的强度,分别在混凝土的下表面附近以及在整个混凝土构件中加入短纤维,对7种不同加固方式的混凝土梁进行了有限元分析,并与试验结果进行对比.结果表明:加入短纤维的FRP加固混凝土结构的裂纹扩展缓慢,韧性得到改善,承载能力明显提高.

Influence of Short Fiber on Carrying Capability of FRP Strengthened RC Beams

Based on the continuous damage theory and considering the shear effect on adhesive,a high-order nonlinear FEM model was developed for the coupling of shear/flexure with in-plane deformation of the RC members strengthened with FRP.When strengthened,most failures were found because of the separation of the concrete surface layer near FRP from the protecting layer of reinforcements and few of them were found on the bonded interface between carbon-fiber cloth and concrete or tack coat.To enhance the strength of whole member especially the interlayer as above,short fibers were added to the RC beam especially the lower layer of concrete.It is revealed that the crack propagation is slow,and the mechanic properties of FRP strengthened RC beam with short fibers are thus improved in ductibility especially in carrying ability.