跨丰沙铁路小曲线半径转体桥设计

Design of the Small Curvature Swivel Bridge Straddling Fengtai-Shacheng Railway

北京地铁14号线跨丰沙铁路节点桥位于右线曲线半径为470 m的曲线上,桥梁主体结构为84+84 m的T构。桥梁转体跨度71+71 m,转体重量7 130 t,转体时球铰中心相对下盘中心向曲线内侧预设偏心1.152 m,转体角度33.46°,桥梁的转体半径和转体跨度在轨道交通转体桥梁的设计和施工领域均为国内首创。比选桥梁方案,从针对桥梁上部结构的非对称主体结构设计、下部结构预偏心设置、施工合拢段位置的选择、施工时对既有铁路线的防护等多方面进行论述和详细介绍。结果表明,通过上部结构非对称设计和转体结构预设偏心,有效地保证了小曲线半径大跨度桥梁转体施工时的平衡和稳定性,大大降低了施工风险。

The bridge of Beijing subway line 14 straddling the Fengtai-Shacheng railway is in the right curve with 470 in radius. The main structure is 84 ＋84 m T-structure one, the bridge swivel span is 71 m, the total swivel weight is 7 130 t, the default pre-set eccentric is 1.152 m and the swivel angle is 33.46° towards the inside of the curve between swivel ball hinge center to lower plate center. The bridge＇ s swivel radius and span are domestic initiative in the field of urban rail transit design and construction. Bridge schemes are compared in detail from asymmetric main body structure design for bridge upper-structure, pre-set eccentric design for bridge sub-structure, location of folded construction and protection on existing railway etc. The results show that, through the asymmetric design for upper-structure and the pre-set eccentric for swivel structure, the balance and stability for long-span bridge swivel construction with small curve radius can be effectively ensured and the construction risk can be reduced greatly.