曲线钢箱梁支座反力分析和脱空控制

哈尔滨市香滨路连续曲线钢箱梁在初始设计支承条件下,最小验算支反力出现负值。为防止桥梁运营阶段支座脱空,对桥梁上、下部结构产生附加病害,根据曲线钢桥特点,采用有限元法及相关推导公式对负支反力产生的主要原因进行分析,经分析,曲线梁桥曲率的存在、横截面尺寸的分布特点以及钢箱梁自重小是导致支座脱空的主要原因。以此为基础,提出设置配重和支座预偏心的综合支座脱空控制方法。实践证明:在梁端配置适当重量后,负支反力会明显减小,再进行适当支座偏移后即可达到设计支反力要求。通过静载试验进一步验证了该法具有良好的实际效果。

Support Reaction Analysis and Control of Bearing Hanging in the Air of Curved Steel Box Girder

Under the initial design supporting condition,the minimal checking support reaction of the bearings of Xiangbin Road Continuous Curved Steel Box Girder Bridge in Harbin shows a negative value.To prevent additional damage from occurring in the superstructure and substructure of the bridge due to the event of bearing hanging in the air and in accordance with the characteristics of curved steel bridge,the finite element method and related derivation formulae are adopted to analyze the main causes leading to negative reaction force.Results of the analysis show that the occurrence of bearing hanging in the air are attributed to the existence of the curvature of the curved steel bridge,the distribution characteristic of the cross section dimension and the small deadweight of box girder.Based on this,a comprehensive method of setting counterweight and bearing eccentricity to control the occurrence of bearing hanging in the air was proposed.Practice has proved that the negative support reaction obviously decreases when proper weight is added to the ends of the girder,and after the bearing is properly offset,the support reaction meets the design requirement,and the method is feasible.Static test further proves that the practical effect of the method is sound.