体外预应力加固重载铁路盖板涵试验研究

Test and Study on the Reinforcement of Heavy Haul Raiway Slab Culvert with External Prestressing

目前大秦铁路运输荷载日趋增加,桥梁的既有损伤不断加重,桥梁不断老化,破损。通过既有盖板涵承载力评估可知,盖板涵混凝土压应力已经超出规范要求。为了改善盖板的受力性能,提高盖板的承载能力,对盖板进行体外预应力加固。根据已加固盖板的室内静载试验和200万次疲劳试验,结合数据研究体外预应力的加固效果。结果表明,体外预应力加固可以大幅度提高盖板的承载能力,在正常使用状态混凝土压应力最大降低约32%。最后,根据力学理论推导体外筋应力增量计算公式,借助试验结果验证理论计算的准确性,为体外预应力加固的实际施工提供理论指导。

With the increase of current railway traffic load, the existing defects of bridges are geeing worse, and bridges are subject to constant ageing and damage. The evaluation of the bearing capacity of the existing slab culvert indicates that the compressive stress of the concrete is beyond the standard requirement. In order to improve the mechanical performances of the cover plate and its bearing capacity, reinforcement with external prestressing is applied to the cover plate. According to the indoor static tests of the reinforced plate and fatigue test of 2000000 times, this paper addresses the effect of external prestressing reinforcement with test data. The results show that external prestressed reinforcement can greatly improve the bearing capacity of cover plate, and the concrete compressive stress is reduced about 32% under normal service condition. Finally, according to mechanical theory, this paper deduces the formula for calculating stress increment of external tendons, verifies the accuracy of theoretical calculation based on t／est results, and provides theoretical guidance for the construction of external prestressing reinforcement.