摘要
为了给钢筋混凝土受弯梁(RC)的复合加固设计和施工提供参考,针对采用TRC面层的预应力CFRP筋嵌入式增强RC受弯梁,考虑TRC层数和开槽间距等因素的影响,对1根普通RC梁和5根复合加固梁进行了四点弯曲加载试验,并对TRC面层的预应力CFRP筋嵌入式增强RC受弯梁破坏形态、承载能力以及使用性能进行了分析。研究结果表明:采用TRC面层的预应力CFRP筋嵌入式复合加固方法可以有效提升梁的承载能力,改善梁在使用荷载下的跨中挠度和最大裂缝宽度;复合加固梁极限荷载随TRC层数的增加有所提升,但较厚的TRC加固层更易发生剥离而退出工作,承载力会因此减小;开槽间距对复合加固梁刚度和承载力无明显影响,但较窄的槽边距会导致复合加固梁发生端部混凝土拉裂破坏,该类破坏导致梁承载力较低,应采取措施避免此类破坏的发生;相比于未加固梁,复合加固梁中性轴高度明显增大,钢筋屈服后,中性轴高度逐渐稳定,曲率变化加快;复合加固梁正常使用极限荷载下的跨中挠度和最大裂缝宽度均在规范规定的限值内,并且远远低于该限值,表现出良好的使用性能;复合加固梁正常使用极限荷载下跨中挠度和最大裂缝宽度的理论值与试验值差距较小,误差总体处于15%~17%范围内,可见规范中计算模型的适用性良好。
To provide a reference for the composite reinforcement design and construction of reinforced concrete(RC)flexural beams,a four-point flexural loading test was conducted on 1 ordinary RC beam and five composite reinforced beams with a TRC surface layer,considering the influence of the TRC layer number and slot spacing.The failure form,bearing capacity,and performance of the embedded reinforced concrete flexural beams with prestressed CFRP bars on the TRC surface were analyzed.The results show that the prestressed CFRP-embedded composite reinforcement method using the TRC surface layer can effectively increase the bearing capacity of the beam as well as improve the mid-span deflection and maximum crack width of the beam under a service load.The ultimate load of the composite reinforced beam increases with the number of TRC layers,but a thicker TRC-reinforced layer is more likely to peel off and withdraw from the work;thus,the bearing capacity will decrease.The slot spacing has no apparent effect on the stiffness and bearing capacity of the composite reinforced beam.However,a narrow slot spacing leads to tensile fracture of the end concrete of the composite reinforced beam,and the bearing capacity of this type of failure is low.Compared with the unreinforced beam,the neutral axis height of the composite reinforced beam increased significantly,the neutral axis height became stable,and the curvature changed faster after the steel bar yielded.The mid-span deflection and maximum crack width of the composite reinforced beam under the normal service limit load are both within the limit value specified in the code and far below the limit value,indicating good service performance.The theoretical and experimental values of the midspan deflection and maximum crack width of the composite reinforced beam under the normal-use limit load are small,and the errors are generally between 15%and 17%,respectively.The applicability of the calculation model to the specifications is good.
作者
骆俊晖
宁杰钧
罗资清
尹世平
刘子瑞
LUO Jun-hui;NING Jie-jun;LUO Zi-qing;YIN Shi-ping;LIU Zi-rui(Guangxi Beitou Transportation Maintenance Technology Group Co.Ltd.,Nanning 530201,Guangxi,China;Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering,China University of Mining and Technology,Xuzhou 221116,Jiangsu,China;State Key Laboratory of Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou 221116,Jiangsu,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2023年第9期193-201,共9页
China Journal of Highway and Transport
基金
2021年度广西交通运输行业重点科技项目
广西科技基地和人才专项(桂科AD23026026)。
关键词
桥梁工程
复合加固梁
四点弯曲试验
嵌入式预应力CFRP筋
TRC层数
开槽间距
bridge engineering
composite reinforced beam
four-point bending test
prestressed near-surface mounted CFRP(NSM-CFRP)
number of TRC layers
slot spacing
