外贴纤维加固梁抗剪承载力计算方法分析

Analysis of shear strength models for beams strengthened by externally bonded FRP composites

在综合分析国际上关于外贴纤维加固混凝土梁斜截面抗剪承载力计算方法现状的基础上 ,分析了斜截面外贴材料应变 (应力 )分布特征、外贴材料与混凝土的最大粘结传力长度和产生梁侧剥离破坏时的最大纤维应变的影响因素 ,采用与在钢筋混凝土梁中钢筋对抗剪承载力贡献计算模式相似的表达方法 ,建立了外贴脆性材料对斜截面抗剪承载力贡献的计算模式 .在该模式中 ,分别对外贴封闭纤维箍加固构件产生纤维拉断破坏和梁侧纤维剥离破坏时相应承载力进行了分析 .

State of the art of the models to predict the shear strength of RC beams strengthened with externally bonded FRP composites is discussed. The strain (or stress) distribution feature of FRP strips intersected by shear crack, the maximum stress transfer length between FRP and concrete, and the maximum strain of FRP strips across the shear crack when FRP debonds from the side faces of beams are studied. A model to predict the contribution of externally bonded FRP composites to shear strength of RC beams is put forward, which has the same style as the contribution of internal steel shear reinforcement. In this model, the shear strengths of FRP strengthened beams with closed strips are considered as two stages, one is the strength when FRP ruptures and the other is the strength when FRP debonds from the side faces of the beams.