【摘要】 研究目的:为研究箱梁发生徐变上拱时底座板与箱梁顶面接触面间发生应力重分布对箱梁徐变上拱的影响,本文在ANSYS有限元平台上建立纵连板式无砟轨道-32 m PC简支箱梁体系的协同工作分析模型,分析混凝土收缩徐变及预应力筋松弛引起的箱梁长期变形及其对滑动层与CA砂浆应力的影响。研究结论:(1)梁-轨体系下箱梁的跨中徐变上拱小于将无砟轨道体系等二期恒载换算成均布荷载施加在单独箱梁结构上的徐变上拱,持荷1 500 d时前者徐变上拱为后者的72. 2%;(2)箱梁徐变上拱使底座板与箱梁之间产生应力重分布,导致梁端附近一段区域的底座板与箱梁之间压应力降低甚至局部出现脱空现象,该区域压应力往跨中方向转移;(3)箱梁徐变上拱亦使底座板及轨道板间发生应力重分布,在梁端附近一段区域的CA砂浆出现拉应力,但底座板与轨道板间尚未脱空;(4)本研究成果揭示了纵连板式无砟轨道-箱梁结构体系的协同工作机理、箱梁长期变形规律及其对层间应力重分布影响,可为深入研究箱梁-轨道体系协同工作提供参考。更多还原

【Abstract】 Research purposes: To study the influence of redistribution of stresses between base plate and top contact surface of box girder on creep camber of box girder,a synergetic analysis model in finite element software ANSYS for the longitudinally connected slab ballastless track-32 m simply supported PC girders is established in this paper,the long-term deflection of box girder caused by shrinkage & creep of concrete and relaxation of prestressed tendons and its effect on stresses in sliding layer and CA mortar are analyzed.Research conclusions:( 1) The long-term creep camber in mid-span of box girder under girder-rail system is less than that of the single box girder which the uniform load converted from the ballastless track system is applied on. The creep camber of the former is 72. 2% of that of the latter at 1500 days of loading.( 2) The creep camber of box girder causes the redistribution of stresses between the base plate and the box girder,which leads to the reduction of the compressive stress in local area near the end of the girder,and even the void beneath base plate. The compressive stresses in this region are shifted to the mid-span direction.( 3) The creep camber of box girder also causes the redistribution of stresses between base plate and track slab and the tensile stress appear in CA mortar in local area near the end of the girder,but the void beneath track slab has not yet occurred.( 4) The research result discloses the synergetic mechanism of the longitudinally connected slab ballastless track-box girder structure system,the long-term deformation law of the box girder and its influence on the stress redistribution between layers,which can provide a valuable reference for further study of the collaborative work of the girder-track system.更多还原