Analysis For Stress And Section Of Thin Walled Box Girder Using In High-speed Railway

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.