钢箱梁横隔板疲劳开裂原因及补强细节研究

发布时间：2018-04-03 10:32

本文选题：桥梁工程　切入点：钢箱梁横隔板　出处：《中国公路学报》2017年03期

【摘要】：针对压-压循环可不验算疲劳、横隔板弧形切口母材疲劳为面外反复变形所致、《公路钢结构桥梁设计规范》(JTG D64—2015)(以下简称《公路钢桥规》)疲劳损伤效应系数取值等认知或规定,以及服役背景工程横隔板弧形切口处补强细节尺寸的确定,通过服役背景工程的疲劳细节、交通载荷与病害特征等信息汇集,服役背景工程多种补强方案、新建背景工程等轮载有限元分析与多规范疲劳验算比较,力求揭示横隔板弧形切口母材疲劳开裂机理,确定其合理的补强细节。研究结果表明:横隔板弧形切口处母材的轮载应力主要为膜压应力,轮载压应力幅耗费横隔板母材疲劳寿命;《公路钢桥规》疲劳损伤效应系数取值或许偏大;弧形切口形状对横隔板与U肋连接处及横隔板母材轮载应力及其峰值影响较大,弧形切口半径不能太小,且其与U肋交点的切线与U肋腹板的夹角宜取小值;横隔板母材裂纹较短者(优化后,裂纹自然切除)可采用"弧形切口优化"的处治方案,较长者可采用"止裂孔+弧形切口优化+双面补强钢板"的处治方案;补强钢板对补强以外稍远部位应力影响可忽略,补强钢板尺寸可统一,其边缘距顶板可取65mm,已覆盖裂纹全长,其边缘距U肋宜取30mm,太近会导致横隔板与U肋连接焊缝处应力增大,其厚度宜取4mm,过厚将在补强钢板边缘处母材上形成新的疲劳敏感点。
[Abstract]:Fatigue can not be checked in the pressure-pressure cycle.The fatigue of the base material of the transverse partition arc notch is caused by repeated deformation outside the plane, the Code for Design of Highway Steel structure Bridges, JTG D64-2015 (hereinafter referred to as "Highway Steel Bridge Regulation"), and so on.As well as the determination of the size of reinforcement details at the arc incision of the transverse diaphragm in the service background engineering. Through the collection of fatigue details, traffic load and disease characteristics of the service background engineering, various reinforcement schemes of the service background engineering are obtained.In order to reveal the fatigue cracking mechanism of the base material of arc incision of transverse partition plate and determine the reasonable reinforcement details, the finite element analysis of iso-wheel load and the fatigue checking calculation of multi-code are compared in this paper.The results show that the wheel load stress of the base metal at the arc notch of the transverse diaphragm is mainly membrane compressive stress, and the amplitude of the wheel load stress consumes the fatigue life of the transverse diaphragm, and the fatigue damage effect coefficient of the highway steel bridge gauge may be too large.The shape of arc notch has a great influence on the stress and peak value of wheel load of transverse diaphragm and U rib, the radius of arc cut can't be too small, and the angle between the tangent line and U rib web should be small.The treatment scheme of "arc notch optimization" can be adopted in the case of short crack in the base metal of the transverse partition (after optimization, the natural excision of the crack), and the treatment scheme of "the arc-shaped notch of the stop hole to optimize the reinforcing steel plate on both sides" can be adopted by the elder.The effect of reinforcing steel plate on the stress of a little further place outside the reinforcement can be neglected. The size of the reinforcing steel plate can be unified. The edge distance from the roof can be 65mm and the crack is covered in the whole length.The edge should be 30 mm away from the U rib, which will cause the stress to increase at the weld joint between the transverse diaphragm and the U rib, and the thickness should be 4 mm. If the thickness is too thick, a new fatigue sensitive point will be formed on the base metal at the edge of the reinforcing steel plate.
【作者单位】：长沙理工大学桥梁工程安全控制教育部重点实验室;
【基金】：国家自然科学基金项目(51308070) 国家重点基础研究发展计划(“九七三”计划)项目(2015CB057701,2015CB057702) 湖南省研究生科研创新项目(CX2016B396) 桥梁工程安全控制教育部重点实验室开放基金项目(16BCX12)
【分类号】：U441.4

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