单线铁路长联大跨连续梁力学特性精细数值分析

Numerical Analysis for Mechanical Properties of Long-span Continuous Girder of Single-track Railway

单线铁路长联大跨连续梁目前较为少见,需精细化分析。本文以国内最大的单线铁路连续梁桥(100+3×180+100)m为依托工程,建立了主梁实体单元等4种数值模型,分析了0号块和跨中截面应力分布状态,对比量化了各模型计算径向力效应和温度效应的差异。研究结果表明:(1)由于支座宽度对负弯矩折减的影响,支点上方的0号块顶板应力明显小于0号和1号块交界处的应力,未考虑此影响的杆系单元模型结果偏于保守;(2)预应力钢束径向力导致底板中部出现横向拉应力,若以主梁实体单元模型中钢束径向力引起的应力为基准,框架杆系单元计算结果偏于不安全;(3)采用主梁杆系单元计算移动荷载作用下跨中截面应力和梯度温度截面应力偏于安全。

The long-span continuous beams of single-track railways are still relatively rare and require detailed analysis. Based on the largest single-line railway continuous beam bridge(100+3×180+100) m in China ,this paper establishes four numerical models such as the main beam solid element. The stress distribution state of the block 0 and the mid-span section is analyzed. The difference between radial force effect and temperature effect calculated by each model is compared and quantified. The research results show that:(1) Due to the effect of the bearing width on the reduction of the negative bending moment,the roof stress of the block 0 above the bearing is significantly less than that at the junction of block 0 and block 1. The results of the bar element model without considering this effect are conservative (2)The radial force of the prestressed steel causes transverse tensile stress in the middle of the bottom. If the stress caused by the radial force of the steel cable in the solid element model of the main beam is taken as the reference,the calculation result of the frame element has security risks.(3) The stress of mid-span section and the stress of gradient temperature section calculated by main beam element under moving load are safe.