钢桥面板横隔板疲劳裂纹维修对未开裂侧的影响

Effect of fatigue crack maintenance on uncracked side stress of steel bridge deck diaphragm

针对不同止裂孔孔径、补强钢板厚度下的疲劳裂纹修复后应力特征,采用数值模拟的方法,建立了不同维修参数下的有限元模型进行了探究。通过提取各工况下右侧横隔板-U肋连接焊缝焊趾部位2条路径上主拉应力进行对比,得到了横隔板-U肋构造细节左侧维修后对右侧重点开裂部位应力的影响。研究结果表明:未维修前,左侧横隔板焊趾裂纹在0~20 mm区间内扩展时,右侧焊趾处的应力水平增幅显著;钻孔止裂法不能有效降低右侧焊趾处开裂的风险。使用较大孔径的止裂孔维修后,右侧焊趾应力会超出维修前的水平,右侧开裂风险加剧;钢板补强法可降低右侧焊趾应力至未开裂前的水平,建议使用与母材厚度相当的钢板进行补强维修,效果较为理想。

According to the stress characteristics of fatigue crack repaired under different aperture and thickness of reinforcing steel plate,the finite element models under different maintenance parameters were established using numerical simulation.By extracting the principal tensile stress of the right diaphragm-U rib joint weld toe under different working conditions and coMParing the two paths,the influence of the left side of diaphragm-U rib structural details on the stress of the right crack point was obtained.The results showedthat the stress level at the right weld toe of the left diaphragm increased significantly when the crack propagates in the range of 0-20 mm before maintenance,and the drilling hole method can not effectively reduce the risk of cracking at the right weld toe.After repairing the crack with larger aperture,the stress of the right weld toe will exceed the level before repairing,and the risk of cracking on the right side will increase.The steel plate reinforcement method can reduce the stress of the right weld toe to the level before cracking.It is suggested that the steel plate with the same thickness as the diaphragm be used for reinforcement and maintenance,while the effect is more ideal.