高速铁路连续梁拱桥拱肋施工方案对比分析

摘要

一座高速铁路桥梁跨越南水北调主干渠,桥型为梁拱组合体系拱桥,其钢管拱肋施工方案由原来的竖向转体施工转变为支架施工.根据高速铁路梁拱组合体系桥梁的结构特点,设计了一种适用于拱肋支架施工的支架结构.结合拱肋竖向转体和支架拼装2种施工方案,采用MIDAS/Civil模拟施工过程,并对各阶段的关键截面内力、应力和竖向位移进行分析.结果表明:设计的支架结构强度、刚度和稳定性验算结果均满足规范和设计要求;与拱肋支架拼装施工方案相比,竖向转体施工方案中拱肋的内力、应力以及竖向位移较大,但亦满足规范和设计要求,2种施工方案均合理可行;从拱肋受力、施工难易程度、经济性、安全性等方面考虑,支架拼装施工方案比竖向转体施工方案更具有优越性.%A high speed railway girder-arch combination arch bridge was constructed across the mail canal of the South-to-North Water Diversion Project.The construction scheme of its steel tube arch rib was changed from the vertical rotation construction to support construction.According to the structure characteristics of the high speed railway girder-arch combination arch bridge,a kind of support structure for the support construction was designed.Combining with the two kinds of construction schemes,the construction process were simulated by using MIDAS/Civil.The internal force,stress and displacement of the key sections were analyzed in each stage.The results show that the strength,stiffness and stability of the support structure all meet the specification and design requirements.The internal force,stress and vertical displacement of arch rib are larger in the vertical rotation construction scheme than the support construction scheme,but the values all meet the specification and design requirements,so the two construction schemes are feasible.The support construction scheme has more advantages than vertical rotation construction scheme in terms of the arch rib stress,degree of construction difficulty,economy and safety.