重载列车荷载与环境因素耦合作用下重载铁路桥梁疲劳损伤演化机理研究

重载铁路在大轴重、长编组、高行车密度作用下，桥梁结构的疲劳损伤开裂问题非常突出，同时工程实践又表明，由于环境因素作用而产生的混凝土结构劣化对其疲劳性能的影响较静力性能的影响严重得多。目前，我国尚无专门针对重载铁路桥梁的设计与评估理论体系，已有的研究也并未充分考虑疲劳荷载与环境因素的耦合作用影响。为此，本项目拟通过试验研究和理论分析研究重载列车荷载作用下重载铁路桥梁疲劳损伤演化机理、环境因素作用下疲劳损伤开裂重载铁路桥梁性能劣化机理以及疲劳荷载与环境作用效应的耦合机制，建立疲劳荷载与环境因素耦合作用效应等效的试验模拟方法，并基于疲劳试验与人工环境模拟试验技术实现重载铁路桥梁在疲劳荷载与环境因素耦合作用下性能演化过程的模拟，通过系列模型试验研究疲劳荷载与环境因素耦合作用下预应力混凝土梁疲劳损伤演化机理和失效模式。研究成果将为重载铁路桥梁的设计、评估和强化提供科学依据。

The railway bridges have exhibited the outstanding fatigue damage and crack problem under the high traffic density condition of big axle load and long marshalling heavy haul trains. It is well documented that the performance of concrete structures exposed to corrosive enviroment is deteriorated due to long-time eroding and the concrete structures subjected to fatigue loading are more obviously than that subjected to static loading. The design and evaluation theoretical system on heavy haul railway bridge is not formed in our country and the coupled effect of fatigue loading and environmental action on structural performance deterioration is not taken into account completely in the literature. Based on experimental and theoretical methods, fatigue damage evolution mechanism of the heavy haul railway bridge under heavy haul strain, structural performance deterioration mechanism of damage and cracking bridge under environmental action and the coupled mechanism of fatigue loading and environmental action are systematically investigated. The experiment simulation method on the equivalent coupling effects of fatigue loading and environment factors will be proposed. The fatigue damage evolution rule for heavy haul railway bridge under the coupling effects is simulated by using experiment technology of fatigue loading and artifical climate simulation. The test project of heavy haul railway bridge under the coupling effect of fatigue loading and environment action will be carried out to research fatigue damage evolution mechanism and failure mode. The results will provide important science basis for design, evaluation and strengthening of heavy haul railway bridge