首页|重载铁路桥梁体外预应力筋加固性能研究

重载铁路桥梁体外预应力筋加固性能研究

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运营提载会导致重载铁路桥梁损伤累积和刚度退化加剧，对重载铁路预应力混凝土桥梁进行加固可以改善桥梁的受力状况，提高桥梁承载能力。为了研究重载铁路桥梁体外预应力筋加固的性能，分别制作重载铁路24 m超低高度预应力混凝土梁的未加固足尺试验模型与体外预应力筋加固足尺试验模型，并开展200万次疲劳试验与疲劳后静力试验。建立未加固预应力混凝土梁与体外预应力筋加固预应力混凝土梁的精细化有限元模型，通过试验与有限元分析，研究加固前后重载铁路预应力混凝土梁的静力与疲劳性能，揭示加固前后梁体挠度和应力变化规律，并分析不同轴重列车作用下加固预应力混凝土梁的力学性能。研究结果表明:重载铁路桥梁外加预应力筋的加固效果良好，疲劳试验中加固梁刚度退化幅度、跨中挠度、梁内预应力筋应力、梁底及下翼缘混凝土应力显著比未加固梁的小;在33 t轴重列车与1。2倍中等荷载(ZH)轴重作用下，外加预应力筋加固的24 m超低高度预应力混凝土梁的适应性良好，预应力混凝土梁挠度与应力响应均符合规范要求。研究结果可为重载铁路桥梁的设计、养护、维护与加固提供基础与参考。
Performance analysis of external prestressing tendons reinforcement for heavy-haul railway bridges
The operational load lifting leads to the problems of strength degradation and stiffness deterioration of bridges for heavy-haul railway,making it crucial to strengthen these structures.In order to investigate the reinforcement performance of heavy-haul railway bridges with external prestressing tendons(EPTs),both fatigue and post-fatigue monotonic tests were conducted on unreinforced and reinforced full-scale 24 m ultra-low height prestressed concrete(PC)beam test models.Finite element(FE)models of unreinforced and reinforced PC beam were established.Through tests and FE analysis,the monotonic and fatigue properties of PC beams for heavy-haul railway before and after reinforcement were studied,and the laws of deflection and stress changes before and after reinforcement were revealed.The mechanical properties of PC beams under the action of different axle weight trains were revealed.The results show that the reinforcement effect is significant.In fatigue tests,the reinforced beams exhibite significantly lower stiffness degradation,mid-span deflection,stress of internal prestressing tendons,and stress in the bottom and lower flange of the concrete compared to the unreinforced beams.In the operation of 33 t axle weight and 1.2 times medium load(ZH)axle weight,the adaptability of 24 m ultra-low-height full-scale PC beams reinforced with external prestressing tendons is excellent,and the deflections and stress responses of 24 m ultra-low-height full-scale PC beam of the reinforced heavy-haul railway meets the specification requirements.The findings can provide useful references for the design,maintenance and strengthening of bridges for heavy-haul railway.

heavy-haul railway bridgereinforcement technologyprestressed concrete beamfatigue testfinite element analysis

宋力、陈岩、刘冉、蒋丽忠、余志武

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中南大学土木工程学院,湖南长沙,410075

高速铁路建造技术国家工程研究中心,湖南长沙,410075

重载铁路桥梁 加固技术 预应力混凝土梁 疲劳试验 有限元分析

国家自然科学基金资助项目国家自然科学基金资助项目国家自然科学基金资助项目国家自然科学基金资助项目中国中铁股份有限公司重大专项

520784925177863152378208513785062020-重大-2

2024

10.11817/j.issn.1672-7207.2024.09.015

中南大学学报(自然科学版)
中南大学

中南大学学报(自然科学版)

CSTPCD北大核心
影响因子：0.938
ISSN：1672-7207
年,卷(期)：2024.55(9)