高速铁路矮塔斜拉桥结构体系参数研究

Research on structural parameters of high-speed railway extradosed cable-stayed bridge

矮塔斜拉桥是塔、梁、索协同受力的结构体系,其刚度分配情况对结构力学特性有决定性影响。建立(142+270+142)m的高速铁路矮塔斜拉桥有限元模型,对比研究了梁高、塔高及无索区长度等关键参数,总结其受力规律并进行了经济性比较。研究表明:塔墩固结体系温度跨度小,可避免设置伸缩调节器,后期养护少;梁端转角是矮塔斜拉桥梁高梁高重要控制因素,随着跨中无索区长度增加,恒载下主梁墩顶负弯矩减小、跨中弯矩增大;桥塔越高,对主梁竖向支撑作用及应力控制越有利,工后徐变控制越容易。综合比较,本桥塔高采用45m,支点梁高14.0m,跨中梁高7.0m,支点无索区长度为44.5m,跨中无索区为18.5m,结构受力及综合性能最优,本研究可为矮塔斜拉桥的设计提供参考。

Extradosed cable-stayed bridge is a structural system in which tower,beam and cable are stressed together.Its stiffness distribution has a decisive impact on the mechanical properties of the structure.The finite element model of(142+270+142)m high-speed railway low pylon cable-stayed bridge is established.The key parameters such as beam height,tower height and length of cable-free zone are compared and studied,and their stress laws are summarized and compared economically.The results show that the temperature span of the tower pier consolidation system is small,the expansion regulator can be avoided,and the later maintenance is less;The beam end angle is an important control factor for the height of the low pylon cable-stayed bridge.With the increase of the length of the cable-free zone in the middle of the span,the negative bending moment at the pier top of the main beam decreases and the bending moment at the middle of the span increases under the dead load;The higher the bridge tower is,the better the vertical support effect and stress control of the main beam will be,and the easier the post construction creep control will be.Through comprehensive comparison,the tower height of this bridge is 45m,the beam height at the fulcrum is 14.0m,the beam height at the midspan is 7.0m,the length of the non cable area at the fulcrum is 44.5M,and the non cable area at the midspan is 18.5M.The structural stress and comprehensive performance are the best.This study can provide a reference for the design of extradosed cable-stayed bridge.