CFRP筋增强混凝土梁抗剪性能试验  

EXPERIMENTAL STUDY ON SHEAR PERFORMANCE OF CFRP-REINFORCED CONCRETE BEAMS

作　　者：陈起建 Chen Qi-jian

机构地区：[1]中铁十一局集团建筑安装工程有限公司,武汉430064

出　　处：《建筑技术开发》2022年第9期108-113,共6页Building Technology Development

摘　　要：针对桥梁和建筑结构中大量使用的碳纤维筋(CFRP)增强混凝土梁的抗剪性能,首先设计箍筋间距和剪跨比不同的3根足尺CFRP筋增强混凝土梁试件,并基于规范要求给出其抗剪性能测试试验工况和加载模式;然后,观察不同工况下试件在两点集中加载方式下裂缝的产生和发展过程,总结归纳CFRP筋混凝土梁的失效模式和破坏特征;同时,由CFRP纵向受力筋和CFRP箍筋的荷载—应变关系及CFRP筋混凝土梁的开裂荷载、极限荷载和荷载–挠度曲线的变化情况,分析研究CFRP筋混凝土梁承载能力和变形性能随剪跨和箍筋间距的变化规律;最后,分析剪跨、箍筋间距等影响因素对CFRP筋混凝土梁裂缝宽度、裂缝数量及裂缝分布的影响规律。结果表明:CFRP筋混凝土梁的剪切破坏由弯剪区贯通斜裂缝发展所致;CFRP箍筋配箍率和剪跨比对开裂荷载影响显著,箍筋配箍率越大,试验梁斜截面开裂荷载和极限破坏荷载增加,但是剪跨比越大梁承载力则明显降低;梁的挠度–荷载曲线呈两段式线性分布,梁破坏时变形明显,裂缝宽度较大,高强CFRP箍筋强度发挥有限。Aiming at the shear performance of carbon fiber reinforcement(CFRP) reinforced concrete beams widely used in bridges and building structures, this paper firstly designs three full-scale CFRP reinforcement reinforced concrete beam specimens with different stirrup spacing and shear span ratio.The specification requires that the test conditions and loading modes of its shear performance test be given. Then, the occurrence and development process of cracks in the specimen under two-point concentrated loading mode under different working conditions are observed, and the failure modes and failure modes of CFRP reinforced concrete beams are summarized.At the same time, according to the load-strain relationship of CFRP longitudinal reinforcement and CFRP stirrups, as well as the changes of cracking load, ultimate load and load-deflection curve of CFRP reinforced concrete beams, the bearing capacity and deformation performance of CFRP reinforced concrete beams are analyzed and studied.The variation law with shear span and stirrup spacing;finally, the influence of shear span, stirrup spacing and other influencing factors on the crack width, number of cracks and crack distribution of CFRP reinforced concrete beams is analyzed.The results show that the shear failure of CFRP reinforced concrete beams is caused by the development of oblique cracks in the bending-shear zone. The CFRP stirrup ratio and shear-span ratio have a significant effect on the cracking load. The cracking load and ultimate failure load increase, but the bearing capacity of the beam decreases significantly as the shear-span ratio increases. The deflection-load curve of the beam is linearly distributed in two sections,the deformation of the beam is obvious, the crack width is larger, and the strength of the high-strength CFRP stirrup is exerted.limited.

关 键 词：CFRP筋混凝土梁 抗剪性能 变形 裂缝 

分 类 号：TU375.1[建筑科学—结构工程]