顶板与竖向加劲肋围焊端部疲劳应力优化方法

RESEARCH ON FATIGUE STRESS OPTIMIZATION FOR WELDED JOINTS BETWEEN STEEL DECK AND VERTICAL STIFFENER

正交异性钢桥面板广泛应用于桥梁工程。在日常车流荷载作用下,顶板与竖向加劲肋构造细节容易发生疲劳损伤。建立该细节局部足尺模型,提出延长加劲肋横桥向长度、设置角钢支撑以及加劲肋开孔三种应力优化方法,以缓解围焊端部应力集中,预防疲劳裂纹的萌生。通过分析围焊端部焊趾处名义应力和热点应力,结合应力集中系数,对比不同措施下围焊端部的应力水平,提出合理的优化参数。研究表明：围焊端部的应力随加劲肋长度的增加而呈线性降低;角钢支撑提高了围焊端部的刚度,降低了应力水平;对加劲肋开孔能截断围焊端部应力流,改善应力集中。

Orthotropic steel bridge deck has been widely used in bridge engineering. The welded joints between steel deck and vertical stiffeners are vulnerable to fatigue damage under wheel loads. The FEM analysis was conducted on the weld of vertical stiffener. Three optimization methods were proposed to prevent fatigue cracking,including extending the length of vertical stiffener,setting angle steel stiffening and opening holes on vertical stiffener. The nominal stress,hot spot stress and stress concentration factor of the weld toe were used to evaluate the effects of different stress optimization methods. The appropriate parameters were proposed. The results showed that the stress at weld end linearly decreased with the increase of the stiffener length. The stress level was effectively reduced due to improved stiffness of weld end through the method of setting angle steel stiffening. The opening of the stiffener could cut off the stress flow at weld end,and the stress concentration was reduced.