【作者】 李力；

【导师】 胡隽；

【作者基本信息】 华中科技大学 ， 桥梁与隧道工程， 2013， 硕士

【摘要】 目前，我国铁路建设正处于高速发展期，已开工修建多条客、货运铁路专线，并且多采用桥梁的结构形式。各条线路均大量采用整孔简支箱梁结构。但与此同时，许多在营运中的混凝土箱梁桥出现了或多或少的工程病害，严重影响了结构安全。本文所涉及的工程实例为某设计速度为250km/h的客货共线铁路，正线无砟双线地段采用单箱双室简支梁，所采用的截面形式与当前客专采用的有明显差别。由于腹肋板变薄、箱室增加等原因，前期城际铁路范围内在预制及施工过程中此种箱梁出现了少许腹板裂缝，本文主要目的是通过结构应力为切入点，观测结构应力状态，来寻求梁结构出现病害的原因，找出解决方法。本文共分基本理论研究，梁应力监测，仿真分析三大块。现场应力监测在考虑到测量精度及经费的前提下，选用钢弦式应变传感器；理论计算主要采用通用空间有限元分析软件Midas Civil进行仿真分析。之后将现场应力监测数据与理论计算值相互比较验证，分析在各个工况下梁的应力、应变状况，讨论裂缝产生的原因。此外，本文还以最不利工况下梁截面上、下翼缘应力、运营状态下梁挠度及混凝土用量为参考指标，计算分析了梁截面各参数对梁受力特性的影响，拟得出一个相对较优的截面形式及对今后的设计提供参考。更多还原

【Abstract】 At present, china’s railway construction is in rapid development period. Somerailway for passenger and freight were bulid on bridge. The bridge structure uses simplesupport box girder. However, series of disease was found in many concrete box-girderbridges, and it’s unsafe for the construction.The thesis was basic on the250km/h Mixed passenger and freight railway line. Atthe site of ballastless track, the railway bridge used double cell girder, which issignificantly different from the girders already used in most passenger dedicated lines.Compare with other box girder, this girder has thinner box webs, and more weight of boxcell. Many cracking was found in such girders at the process of precast and construction.The purpose of this paper is to find the causes of the cracking and get the solutions, byobserved the stress state of girder structure.This paper has three main parts: basic theoretical research、strain monitoring andsimulation analysis. In the consideration of the measurement accuracy and funding, wirestrain gauge was chose; and finite element analysis software Midas Civil was chose forsimulation analysis. In order to find the cause of cracking, monitoring data and thetheoretical results were compared, and the stress and strain situation of this girder atdifferent conditions were discussed and analyzed. The stress of the top and bottom flangeof the girder cross-section under the most unfavorable load, deflection during operators,usage amount of concrete were used as indicators, which used to calculate and analyze theinfluence of every section parameters to the stress and strain for this girder, and get abetter section. It provides a reference for future design.更多还原