多病害预应力空心板梁桥承载性能试验研究

Experimental Study on Bearing Capacity for Prestressed Concrete Hollow Slab Beam Bridge with Severe Diseases

为评估既有病害对桥梁承载性能的影响,以某座跨多条铁路线的预应力混凝土空心板梁桥为背景,通过原位静载试验对其承载能力开展研究。根据铁路运营安全保障要求,选择不同试验孔对桥梁挠度、应变、裂缝宽度变化以及上拱度进行测试,并利用数值模拟计算挠度与应变的理论值。在此基础上对桥梁结构校验系数与横向分布系数进行分析,并综合各项试验结果评估该桥承载性能。结果表明:结构校验系数分布在0.22~0.51间,且实测横向分布系数与理论值吻合良好;梁底纵向裂缝宽度在荷载作用下没有明显变化,裂缝的产生与汽车荷载关系较小;空心板梁上拱度介于32.8~43.2 mm,梁体具有充足的预压力。

To evaluate the influence of existing diseases on the bearing capacity of bridges,taking a prestressed concrete hollow slab beam bridge across railway lines as the case,a in-situ static load test was implemented to investigate the bearing capacity of the bridge.According to the requirements for guaranteeing the safety of railway operation,the deflection,strain,development of crack width as well as the camber of the bridge were measured in different test bridge spans.The theoretical values of deflection and strain were calculated by using numerical simulation.On that basis,the structural calibration coefficient and transverse distribution coefficient of the bridge were analyzed.Thus the bearing capacity of the bridge was evaluated comprehensively.The results show that the calibration coefficients are distributed between 0.22 and 0.51.The measured transverse distribution coefficients are in good agreement with the theoretical values.The width of the longitudinal crack at the bottom of the beam does not change significantly with the test load,the occurrence of the crack has little relationship with the vehicle load.The camber of the hollow slab beams in the range of 32.8 mm to 42.3 mm,indicating that the beams have sufficient prestress.