基于WIM数据和断裂力学方法的钢桥疲劳强度评估

发布时间：2018-05-21 17:11

本文选题：桥梁工程 + 应力强度因子　；参考：《公路交通科技》2017年12期

【摘要】：为了准确评估钢桥焊接结构的疲劳强度,基于断裂力学K判据对于高周疲劳的适用性分析,采用Pairs公式并结合有限元方法和G*积分理论,计算获得了钢桥典型构造细节的应力强度因子表达式。结果表明:钢桥棱角焊缝构造细节和T形接头对接焊缝构造细节的应力强度因子均与结构裂纹尺寸密切相关,其表示式可以由裂纹尺寸、工作应力及结构尺寸等参数联合表达。以构造细节的应力强度因子为基础,计算得到了典型构造细节的等效200万次疲劳强度,并与各国规范及疲劳试验结果进行了对比分析。结果表明:采用断裂力学方法获得的疲劳强度结果与规范值及试验值均吻合良好,对应棱角焊缝构造细节的计算偏差基本在10%以内;对应T形接头对接焊缝细节的计算偏差在20%以内,且T形接头构造细节的疲劳强度远低于棱角焊缝构造细节的疲劳强度,设计和施工中需引起重视。基于坝陵河大桥动态称重系统实测数据,计算获得了钢桁梁节点构造的等效应力幅,并采用上述断裂力学方法评估了该节点构造的疲劳强度和寿命。通过坝陵河大桥节点疲劳模型试验,进一步验证了该方法在钢桥疲劳强度评估上的适用性,研究成果可为钢结构桥梁的强度评估提供借鉴和参考。
[Abstract]:In order to accurately evaluate the fatigue strength of welded structures of steel bridges, based on the applicability analysis of K criterion of fracture mechanics to high cycle fatigue, the Pairs formula and the finite element method and G* integral theory are adopted. The expression of stress intensity factor for typical structural details of steel bridge is obtained. The results show that the stress intensity factors of steel bridge and T-joint butt weld are closely related to the crack size, and the expression can be expressed by the parameters such as crack size, working stress and structure size. Based on the stress intensity factor of structural details, the equivalent 2 million fatigue strength of typical structural details is calculated and compared with the national codes and fatigue test results. The results show that the fatigue strength obtained by the fracture mechanics method is in good agreement with the standard value and the test value, and the calculation deviation for the structural details of the corner weld is less than 10%. The calculation deviation of butt weld details corresponding to T-joints is less than 20%, and the fatigue strength of the structural details of T-joints is much lower than that of corner welds, so attention should be paid to the design and construction of T-joints. Based on the measured data of the dynamic weighing system of the Baling River Bridge, the equivalent stress amplitude of the steel truss joint is obtained, and the fatigue strength and life of the joint structure are evaluated by the above fracture mechanics method. The applicability of this method to the fatigue strength assessment of steel bridges is further verified by the fatigue model test of the joint of the Baling River Bridge. The research results can be used for reference and reference for the strength assessment of steel bridges.
【作者单位】：中南大学土木工程学院;湖南省交通规划勘察设计院;合肥工业大学土木与水利工程学院;
【基金】：国家自然科学基金项目(51078357)
【分类号】：U441.4

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