重载铁路连续刚构桥徐变精细化数值分析

Refined analysis of creep effect for heavy haul railway continuous rigid frame bridge

为了研究重载铁路连续刚构桥的空间徐变效应,通过ANSYS UPFs(user programmable features)功能进行本构关系二次开发,实现了桥梁徐变计算。依托山西省最大的重载铁路连续刚构桥为背景工程开展研究,采用空间壳模型模拟箱梁,空间梁单元模拟桥墩,考虑了连续刚构桥的施工过程,开展了重载铁路连续刚构桥的空间精细化数值分析。对比分析了空间数值模型和梁模型的长期下挠特性,同时对比了不同规范对计算结果的影响。研究结果表明:考虑空间徐变效应后梁体的长期变形发生了较大变化,壳单元模型的竖向下挠量比梁单元模型增加了25%左右。B3模型的计算下挠度比JTG D62—2004规范和TB规范大,需要采用B3模型进行桥梁长期变形验算。

To study the space creep effect of heavy haul railway continuous rigid frame bridge, constitutive relation of concrete creep was modified by user programmable features （UPFs） of ANSYS software. Based on the largest heavy haul railway in Shanxi province, creep research of bridge was conducted. Box girders were simulated by shell element and piers by spatial beam elements. Considering the construction process of a continuous rigid frame bridge, refined analysis of three dimensional creep effect for heavy haul railway continuous rigid frame bridge was carried out. The resuits of refined analysis model and beam model were compared. Difference between different design standard was compared. The results showed that major changes happened in the long-term deformation of beam body if spatial creep effect was considered. The vertical deflection of the shell element increased about 25 % than that of the beam model. Vertical deflection value based on B3 model was larger than that based on JTG D62-2004 design standard and TB design standard, and B3 model should be utilized to compute long-term deformation of box girder bridge.