郑万铁路上跨郑西客专联络线特大桥主桥转体结构分析

郑万铁路上跨郑西客专联络线特大桥为主跨138 m独塔斜拉桥,该桥位于半径1 400 m曲线上,采用国内最大横向偏心球铰(偏心距0.847 m),其可靠性与稳定性对保证施工安全至关重要。基于空间有限元软件Midas FEA分析转体结构在施工过程中的局部应力分布,并研究预应力筋对转体结构力学性能的影响。结果表明:(1)转体结构整体处于较低的应力状态,局部存在应力集中,可通过构造措施保证其力学性能;(2)预应力筋的配置可大幅减小由于局部承压而产生的拉应力,确保转体施工中上下转盘的结构安全;(3)通过设置预偏心,实现了转体施工在大跨度小曲线斜拉桥上的成功运用,降低了桥面配重和转体重力。上述研究成果可为同类型桥梁转体施工提供重要借鉴。

Analysis of the Rotary Structure of the Extra-long Bridge Crossing-over Zhengzhou-Xian Railway Line on Zhengzhou-Wanzhou Dedicated Passenger Tie-Line

The bridge on Zhengzhou-Wanzhou dedicated passenger tie-line crossing-over Zhengzhou-Xian line is a single pylon cable-stayed bridge with a main span of 138 m and is the longest railway curved cable-stayed swing bridge. The bridge located on a 1400 m curve line is equipped with the largest lateral eccentricity spherical hinge(SH) in China,and its reliability and stability are of great importance to ensure the construction safety. The paper analyzes the stress distribution of the SH during the rotation construction based on the Midas FEA program. The effect of prestressed tendons on the mechanical property of the SH is also analyzed. Results indicate that:(1) the entire rotation structure is subject to a low stress with only some local stress concentration,which can be solved by some structural measures;(2) the tensile stress in some local areas can be greatly reduced by prestressed tendons so that safety rotation construction can be ensured;(3) the setting of eccentric displacement enables the application of rotation construction on the long-span small-curved cable-stayed bridge,thus,the additional weight on the deck and the swivel weight is greatly reduced. The above results may provide references for the construction of similar bridges.