变宽度连续箱梁桥空间力学性能分析

摘要

Continuous box⁃girder bridge with variable⁃width is widely used in transportation construction. However, there is few study about the special structure. Taking a multi⁃span continuous box bridge with variable width of the intercity railway between Zhengzhou and Xinzheng international airport as an example, the influence of variable width section on the space me⁃chanical properties of continuous girder bridge was studied, taking into account of transverse effect of girder. Based on spatial beam element model, the feature of internal force, stress as well as displacement was obtained under dead load, prestressed load, temperature load and live load. The results indicated that torsion, reaching its maximum at bearing of the first span, was greatly influenced by the width of the cross section. And bearing bending moment and shearing force increased with wider beam under the action of self weight. The analysis results had reference value for the design of similar bridges.%横向变宽度桥梁在交通建设中被广泛采用，但对这种特殊结构的分析研究较少。本文以郑机城际铁路多跨变宽度连续箱梁桥为例，考虑主梁横向协同工作效应，研究截面宽度变化对连续梁桥空间受力特性的影响规律。通过建立空间梁单元模型，得到恒载、预应力荷载、温度作用和列车活载等荷载作用下箱梁的内力、正应力和位移分布特征。结果表明：变截面宽度对扭矩影响较大，在宽度较大的第一跨支座处达到最大扭矩值；自重作用下，支座处弯矩及剪力随着梁宽度变大而增大。分析结果对设计同类桥梁有参考价值。