高速铁路悬臂现浇连续梁桥后期徐变影响因素分析

长期荷载作用下,徐变将引起大跨度预应力混凝土连续梁桥的上拱或下挠。为满足现行高速铁路的高平顺性及高稳定性要求,大部分均采用无砟轨道,但其可调性很小。通过建立多座不同跨度的连续梁有限元模型,分析了混凝土弹性模量E、预应力张拉龄期τ、不同徐变计算模式及二恒铺装时间等主要因素对后期徐变的影响。结果表明,混凝土弹性模量必须达到设计要求;预应力张拉时混凝土龄期根据具体计算结果可适当调整;不同徐变计算模式差异大;延长二恒铺装时间可显著减小徐变变形。

Analysis of Influence Factors on Creep Deformation in Later Period of Cast-in-situ Continuous Girder Bridge by Cantilever Method on High-speed Railway

Under the action of long-term loads,the creep deformation will cause the upwarp and downwarp of large-span prestressed-concrete continuous girder bridge.The ballastless track can meet the requirements of high smoothness and high stability of current high-speed railway code,but the adjustability is small.Through establishing finite element models for several continuous girders with different spans,the influences on creep deformation in later period because of the main factors were analyzed,including the concrete elastic modulus E,pre-stressed concrete tension age τ,different creep deformation calculation model,and the time of the second-order dead load.The results show that the elastic modulus of concrete must meet the design requirements,the concrete age when tensioning the tendons may be properly adjusted according to specific calculation results,the differences among the calculation results of different creep deformation calculation models are larger,and postponing the time of the second-order dead load can reduce the creep deformation obviously.