| Ballastless tracks can adapt to high-speed railway with high smoothness and high stability, but without a high adjustbility. Post creep deformation effect of prestressed concrete will cause the bridge arch and deflect, resulting in track irregularity. At present, ballastless high-speed railway bridge in Europe, Japan and other countries have been used very widely , but only in small and medium-sized span. The large span bridge over 100m application is very few. Recently, China's high-speed railway experienced rapid development with ballastless track applied to the larger span of the bridge. Thus, how to control the post deformation become the very important issue that bridge engineers are concerned about.This paper takes a continuous rigid frame of a Ballastless bridge (104m +168 m×2 +112 m) as the study background. There are many external factors of creep deformation such as cement varieties, aggregate type, water-lime ratio, cement and also some internal factors such as stress, temperature, loading age and construction defects. High-speed railway of ballastless track deformation control is very demanding. The deformation before laying track can be adjusted for some extent, but post creep deformation is hard to adjust . According to the railway design specification, ballastless track with a deformation more than 5,000/L or 2cm can not endure the tension generated by high-speed lane. Therefore, to long-span Bridges, due to the large span , the post creep deformation, will influence the operational performance of the bridge and can be a threat to the smoothness, stability and safty of driving.From the perspectives of the creep factor, paving time, the bridge structure, and prestressed steel beam configuration, this paper will analyze various factors on the post creep deformation before and after laying track. The author intents to put forward appropriates measures and methods to reduce the creep deformation for future long-span bridge with Ballastless building. |
