薛巧蕊 朱涵

摘要 以北京豐台站六线简支钢箱叠合拱桥为工程背景，利用MIDAS/Civil建立六线简支钢箱叠合拱桥的有限元模型，对成桥状态下的拱肋在不同工况下的受力情况进行分析，在三线偏载情况下拱肋竖向位移达到最大值129.3 mm，比六线全载情况下稍增加3.7 mm，拱肋最大压应力达到208 MPa，比六线全载情况下稍增加7 MPa，在三线偏载情况下对拱肋受力最不利，但拱肋位移及应力均满足规范要求，在使用阶段的安全性得以保证。分析了温度对拱肋位移的影响，拱肋各部位竖向位移变化呈抛物线形，随着拱肋与拱脚之间距离的增加，竖向位移值增大，在拱顶处达到最大值，拟合出了拱肋位移与温度之间的关系，为预测六线简支钢箱叠合拱桥的温度变形提供相关依据;同时分析了拱肋与主梁刚度比变化对拱顶在不同温度下的竖向位移进行了分析，提高拱肋刚度可以减小拱肋竖向位移。

关 键 词 钢箱叠合;拱肋;受力分析;温度;刚度比

中图分类号 U448.22     文献标志码 A

Mechanical analysis of arch rib of six-line simply supported steel box composite arch bridge

XUE Qiaorui1，2， ZHU Han1

（1. College of Architectural Engineering， Tianjin University， Tianjin 300072， China; 2. China Railway Sixth Group Tianjin Railway Construction Co Ltd， Tianjin 300232， China）

Abstract Based on the engineering background of Beijing Fengtai Station six-line simply supported steel box composite arch bridge， the finite element model of six-line simply supported steel box composite arch bridge is established by MIDAS/Civil. The stress of arch rib under different working conditions is analyzed. The maximum vertical displacement of arch rib is 129.3 mm under three-line eccentric load， which is 3.7 mm higher than that under six-line full load， and the maximum compressive stress of arch rib is 208 MPa， which is 7 MPa higher than that under six-line full load. When under three-line eccentric load， the stress of arch rib is the most disadvantageous. However， the displacement and stress of the arch rib meet the requirements of the code， and the safety of the arch rib can be guaranteed in the use stage. The influence of temperature on the displacement of arch rib is analyzed. The vertical displacement of each part of arch rib changes in a parabolic shape. With the increase of the distance between arch rib and arch foot， the value of vertical displacement increases and reaches the maximum value at the arch top. The relationship between the displacement of arch rib and temperature is fitted， which provides a relevant basis for predicting the temperature deformation of six-line simply supported steel box composite arch bridge. At the same time， the vertical displacement of the arch roof at different temperatures is analyzed when the stiffness ratio of the arch rib to the main beam is changed. The vertical displacement of the arch rib can be reduced by increasing the stiffness of the arch rib.

Key words steel box overlap; arch rib; force analysis; temperature; stiffness ratio

0 引言

世界上第1座钢拱桥是1874年美国建造的跨越密西西比河的三跨钢桁架拱[1]。钢结构与混凝土结构相比，具有抗拉性能好、自重小等特点。近年来，随着科学技术的进步，作为大跨度桥梁形式之一的钢拱桥得到迅速发展，其跨径逐步增大，结构形式日新月异。

钢箱叠合拱桥作为一种结构新颖的钢拱桥，因跨越能力强、刚度大、造型美观、桥下净空较大等特点，被我国高速铁路桥梁建设所应用。……