摘要
【目标】为了给RC梁的复合加固设计和施工提供参考,采用TRC面层的预应力CFRP筋嵌入式增强RC梁,探究预应力施加状态和不同加固方式对梁抗弯性能的影响。【方法】对1根普通RC梁和3根加固梁进行四点弯曲加载试验,并对加固后的梁破坏模式、不同阶段荷载、裂缝分布和裂缝宽度及筋材应变进行分析。采用截面分析方法,构建了TRC复合嵌入式CFRP筋加固RC梁的承载力计算公式,预测其极限承载能力。【结果】相较于未加固的普通钢筋混凝土梁,复合加固梁开裂荷载、屈服荷载和极限荷载均有显著提升,且增幅均优于TRC加固梁。对于复合加固梁,施加预应力相较于未施加预应力开裂荷载提高显著,而对屈服荷载和极限荷载无明显影响;复合加固梁的抗弯刚度明显高于未加固梁和TRC加固梁;复合加固梁裂缝具有微细密集的形态特征,且施加预应力与否对复合加固梁的裂缝数量和分布影响较小;通过纤维编织网与CFRP筋协同作用可以有效降低梁下部纵筋应力水平。复合加固梁在加载全程呈现协调变形特征,其截面在受弯过程中仍保持平面,符合平截面假定。其极限承载能力的计算值与实测值偏差小于10%,说明了该模型具有良好的适用性。【结论】复合加固能显著提升RC梁正截面承载性能,提出的承载力计算方法为工程加固设计提供了有效依据。
[Objective]To provide references for the composite reinforcement design and construction of RC beams,the prestressed carbon fiber-reinforced polymer(CFRP)bars embedded RC beams with textile reinforced concrete(TRC)layer were adopted.This study investigated the influences of prestress state and different reinforcement methods on the bending resistance of beams.[Method]The four-point bending tests were conducted on one conventional RC beam and three reinforced beams.The failure modes,load levels at different stages,crack distribution and width,as well as the strain of reinforcing materials of the reinforced beams were analyzed.A sectional analysis method was employed to develop the bearing capacity formula for RC beams reinforced with TRC and embedded CFRP bars.[Result]Compared with the unreinforced RC beams,the composite reinforced beams exhibit significant higher cracking,yield,and ultimate loads.The magnitudes of these improvements consistly supass those achieved by TRC-only reinforcement.For the composite-reinforced beams,the application of prestress notably enhances the cracking load compared with the non-prestressed counterparts,while having negligible influence on the yielding and ultimate loads.The flexural stiffness of composite-reinforced beams is significantly higher than that of both unreinforced and TRC-reinforced beams.The cracks in composite-reinforced beams are characterized by their fine and dense distribution.The number and distribution of cracks in composite-reinforced beams are less affected by whether prestress is applied or not.The synergistic interaction between fiber textile and CFRP bars cn effectively reduce the stress level of longitudinal reinforcement at beam bottom.The cross-sections remain planar during bending,thus verifying the validity of plane section assumption.The calculated ultimate bearing capacity deviated by less than 10%from the measured values,demonstrating the good applicability of the proposed model.[Conclusion]The composite reinforcement can significantly improve the bearing capacity of RC beams.The proposed calculation method for bearing capacity provides an effective basis for engineering reinforcement design.
作者
宁杰钧
罗资清
骆俊晖
尹世平
刘子瑞
NING Jiejun;LUO Ziqing;LUO Junhui;YIN Shiping;LIU Zirui(Guangxi Beitou Transportation Maintenance Technology Group Co.,Ltd.,Nanning,Guangxi 530201,China;Jiangsu Key Laboratory of Disaster Impact and Intelligent Prevention in Civil Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)
出处
《公路交通科技》
北大核心
2025年第8期148-157,共10页
Journal of Highway and Transportation Research and Development
基金
广西重点研发计划项目(AB17292062)
广西科技基地和人才专项(桂科AD23036026)。
关键词
桥梁工程
抗弯性能
静载试验
复合加固梁
预应力CFRP筋
织物增强混凝土
承载力计算
bridge engineering
bending resistance
static load test
composite reinforced beam
prestressed CFRP bars
textile reinforced concrete
bearing capacity calculation
