福厦高铁(95+125) m非对称独塔部分斜拉桥设计

Design of Partial Cable-stayed Bridge with Asymmetric Single Tower(95+125)m for Fuzhou-Xiamen High-speed Railway

新建福州至厦门铁路太城溪特大桥跨越沈海高速公路,斜交角度较大,为减少对高速公路的影响,主桥采用(95+125)m非对称独塔部分斜拉桥方案。对桥体结构体系、主梁梁高、桥塔高度、非对称索力等结构参数进行对比研究,确定合理的结构形式。结果表明:(1)非对称独塔斜拉桥在不设辅助跨的情况下,采用塔梁墩固结体系能有效提高结构刚度,减小梁部后期徐变,采用墩塔梁固结体系徐变值减小约50%,梁端转角减小约40%;(2)为满足高速铁路无砟轨道梁端转角的限值要求,桥体跨中梁高最小5.3m;(3)随着桥塔高度的增加斜拉索对主梁的加劲效果明显,主梁受力得到有效改善,徐变显著减小;(4)通过不平衡索力的合理选择,有效改善了梁部的结构受力,桥体小跨侧与大跨侧索力比值取1.1时受力最佳。该桥转体质量达3.8万t。

Taichengxi super long bridge of Fuzhou-Xiamen high-speed railway crosses Shenyang-Haikou expressway with large skew angle.In order to reduce the impact on the expressway,the main bridge adopts the scheme of(95+125)m asymmetric single tower partial cable-stayed Bridge.The structural parameters of the bridge,such as the structural system,the height of the main beam,the height of the tower and the asymmetric cable force,are compared and studied to determine the reasonable structural form.The results show that:(1)In the case of no auxiliary span,the tower beam pier consolidation system can effectively improve the structural stiffness and reduce the late creep of the beam.The creep value of the bridge with pier tower beam consolidation system is reduced by about 50%,and the beam end angle is reduced by about 40%;(2)In order to meet the limit requirements of beam end angle of ballastless track of high-speed railway,the minimum beam height in the middle span of the bridge is 5.3 m;(3)With the increase of tower height,the effect of stay cable on the main girder is obvious,the stress of main beam can be effectively improved,and the creep is significantly reduced;(4)Through reasonable selection of unbalanced cable force,the structural stress of beam can be effectively improved.The ratio of cable force between small span side and large span side is 1.1.The swivel tonnage is 38000 tons.