大跨度预应力混凝土无碴轨道连续梁桥后期徐变变形的研究.pdf

摘要无碴轨道结构在高速铁路上的大量铺设已成为发展趋势。但对于桥上无碴轨道结构而言,由于没有道碴来调节轨道的高程,很难保证轨道的平顺性。因此必须了解并控制轨道铺设后混凝土桥梁的徐变变形即后期徐变变形。本文从混凝土收缩徐变的机理、影响收缩徐变的因素、徐变系数的计算及收缩徐变的基本计算方法出发,对广州至珠海(含中山至江门)城际快速轨道交通工程上的一座大跨度预应力混凝土无碴轨道连续梁桥进行了后期徐变变形的分析研究。主要完成了以下工作: 。结果表明:中国现行规范中铁05规范和中交04规范的徐变计算结果与实测值相比都偏大。 ,并针对预应力混凝土结构的徐变计算方法进行了研究,同时对目前常用分析软件的徐变计算功能进行了对比研究。常用软件对徐变的计算方法和预应力的处理也有不同,在计算时应引起注意。 ,按不同的规范对广珠无碴轨道(85+135+85)m预应力混凝土连续梁桥进行了后期徐变变形分析。按中铁05规范计算的结果比中交04规范大两倍多。 ,并提出了一些减少后期徐变变形的方法。结果表明:徐变和预应力损失对预应力混凝土连续梁桥的后期徐变变形影响较大,收缩影响较小。可以通过调整合拢时间、铺设二恒的时间和顺序及跨中顶、底板预应力钢束对预应力混凝土连续梁桥的后期徐变变形进行控制。本文研究成果,为该桥的设计和施工提供了依据,也为其它同类型桥梁的后期徐变变形计算及控制提供了参考。关键词:无碴轨道,徐变变形,连续梁,大跨度 ABSTRACT Amount laying of ballastless track on high speed railway has e iSvery difficult to ensure thesmoothness of thetrack because the height ofthetrack can beadjusted little without ballast. Therefore,it iSnecessary toknow and control thecreep deformation of concrete bridges after laying track,namely post creep deformation. According to the mechanism of shrinkage and creep,the influences factors ofshrinkage andcreep,the calculation ofcreep coefficients,the basic methods ofshrinkage and creep thepostcreep deformation of a long span prestressed concrete continuous beam bridge which iS on Guangzhou toZhuhai intercity railtrafficengineering hasbeen calculated. Themajor work ofthisPaper is asfollows: calculated ere印coe伍cients according totheformularies in theseveral current codes pared with themeasured results showed thattheere印coefficients ofChinese Railway 05Code and Chinese Highway 04Code are both greater thanthemeasured values. basic theories and methods of ereep calculation were analyzed,and some research was done on the methods ofcreep calculation ofprestressed concrete structure,and thecalculation function ofere印deformation of mon used softwares were are much difference inthecalculation of creep and