预应力碳纤维板加固重载铁路T梁的效果研究  

Study on Effect of T Girder in Service of Heavy Haul Railway Based on Prestressed CFRP Plate Reinforcement

作　　者：许宏伟[1,2] 武启帆 刘永前[1,2] 李勇[1,2] XU Hongwei;WU Qifan;LIU Yongqian;LI Yong(Key Laboratory of Roads and Railway Engineering Safety Control,Shijiazhuang Tiedao University,Ministry of Education,Shijiazhuang 050043,China;Key Laboratory of Large Structure Health Monitoring and Control,Shijiazhuang Tiedao University,Hebei province,Shijiazhuang 050043,China)

机构地区：[1]石家庄铁道大学道路与铁道工程安全保障教育部重点实验室,石家庄050043 [2]石家庄铁道大学河北省大型结构健康诊断与控制重点实验室,石家庄050043

出　　处：《铁道标准设计》2023年第11期84-91,共8页Railway Standard Design

基　　金：河北省重点研发计划项目(20375410D,21375403D);河北省自然科学基金项目(E2020210017);石家庄铁道大学优秀青年科学基金项目(201801);河北省研究生创新研究基金项目(CXZZSS2022109,CXZZSS2022110)。

摘　　要：随着部分货运铁路扩能改造为重载运输铁路,在役钢筋混凝土桥梁不仅承受重载列车的大轴重,同时,列车加载次数也显著增加,极大地影响了桥梁的正常使用功能,导致梁出现开裂、钢筋锈蚀等病害,因此,需要采用加固技术来合理提升梁的承载能力和适应性。以一孔运营了20年的跨径12 m在役钢筋混凝土T梁为研究对象,选择其中1片未加固T梁开展静力加载弯曲破坏试验,探讨在役钢筋混凝土T梁在不同荷载作用下的损伤演化规律;同时对另1片梁通过在梁底张拉5块预应力碳纤维板进行加固并开展弯曲破坏试验,对加固效果进行验证;通过理论计算及现场试验探究试验梁加固前后在不同等级荷载作用下的钢筋应力、裂缝和变形发展规律。研究结果表明:采用体外预应力碳纤维板加固后,在役钢筋混凝土T梁的梁体刚度得到有效提高;虽然采用预应力碳纤维板加固无法提高梁体的抗裂性能,但对于梁上已产生的裂缝发展起到了有效控制,提高了构件的使用性能;在最不利列车荷载作用下,梁体混凝土及钢筋应力分别下降24.15%、47.68%,裂缝宽度下降66.68%、跨中挠度下降16.31%,且计算结果与试验结果基本一致,加固效果显著,能够满足运营需求。With the expansion of some freight railways into heavy haul transport railways,in-service reinforced concrete bridges not only bear the heavy axle load of heavy haul trains,but also significantly increase the number of loading trains,which greatly affects the normal use of the bridge,resulting in cracks in beams,reinforcement corrosion and other diseases.As a result,the ultimate bearing capacity and operation safety of beams need to be reasonably enhanced by reinforcement technology.Taking an in-service reinforced concrete T-beam with a span of 12 m in service for 20 years as the research object,one unstrengthened T-beam was selected to carry out static load destructive bending test,and the damage evolution law of in-service reinforced concrete T-beam under different loads was discussed.At the same time,the other beam was modified by the tensioning of five prestressed carbon fiber reinforced plastic(CFRP) plates at the bottom of the beam,and the bending failure test was carried out to verify the strengthening effect.Through theoretical calculation and field test,the development law of steel bar stress,crack and deformation before and after strengthened of test beam under different load levels is explored.The results show that the beam stiffness of the in-service reinforced concrete T-beam has been effectively improved after the strengthening with external prestressed CFRP plates.Although the crack resistance of the beam cannot be improved by using prestressed CFRP plates strengthened,it has played an effective control effect on the crack development on the beam and improved the performance of the components.When the test beam was subjected to the most unfavorable load,the stress of concrete and reinforcement decreased by 24.15% and 47.68%,the crack width decreased by 66.68%,and the mid-span deformation decreased by 16.31%.The calculation results were basically consistent with the test results,and the reinforcement effect was remarkable,which can meet the operational requirements.

关 键 词：重载铁路 在役钢筋混凝土T梁 预应力碳纤维板 加固技术 破坏试验 

分 类 号：U24[交通运输工程—道路与铁道工程] U445.7[建筑科学—桥梁与隧道工程]