既有线铁路框架桥改造设计

唐山市龙泽南路（复兴路）下穿七滦铁路立交桥改造工程，由于轨面高差大，既有建筑物多，涉及到拆桥和抬道等技术困难，设计时需要考虑的因素多，设计上有较大的创新。通过合理布孔，线路加固和工作坑防护及路基注浆的优化设计，达到了预期的效果，为以后类似复杂的既有线桥梁改造积累了宝贵的经验。

Rebuilding Design of Frame Bridge on Existing Railway

In the rebuilding project of Qiluan railway frame bridgein Tangshan City, with big difference in track surface elevation and with many existing buildings, the design has to consider many factors and technological difficulties to be involved in construction, such as removing the old structure and lift the road. Through the optimization design of reasonable hole layout, line reinforcement and working pit protection and subgrade grouting, the desired results are achieved, which may provide valuable experience for future transformation of similar complex bridges of existing railways.