采用支撑杆件提高钢箱梁正交异性板疲劳性能研究

交通运输的迅速发展使得钢箱梁正交异性板的疲劳问题日趋突出。为研究设置支撑杆件对钢箱梁正交异性板疲劳性能的影响，制作试件进行室内试验，并采用有限元软件ABAQUS建立有限元模型，分析在无支撑杆件和有支撑杆件的情况下，钢箱梁正交异性板易疲劳开裂位置应力幅（最大荷载时的应力与无荷载时应力之差）的变化。试验和有限元对比结果表明：试验结果和有限元模拟结果吻合良好，支撑杆件的设置可将钢箱梁正交异性板U肋及T肋开槽处的应力幅减小约40%~60%，其中个别位置应力幅减小占比（无、有支撑时的应力幅差值与无支撑时应力幅之比）可达70%；支撑杆件的设置可将顶板跨中位置应力幅减小约20%~40%，其中个别位置应力幅减小占比可达50%。有限元参数分析结果表明：离支撑杆位置越近，开槽位置处的应力幅减小占比越大；随着支撑杆件直径的增大，应力幅减小占比增大，但增大幅度逐渐减小。合理使用支撑杆件能有效减小钢箱梁正交异性板易疲劳开裂部位的应力幅，可在较低的成本下减少钢箱梁正交异性板疲劳破坏的发生，提高其疲劳寿命。

Study on improving fatigue performance of orthotropic plate of steel box girder by using supporting bars

With the rapid development of transportation, the fatigue problem of orthotropic plate of steel box girder becomes increasingly prominent. In order to study the effect of supporting bars on fatigue performance of orthotropic plate of steel box girder, a laboratory test was carried out, and the finite element model was established at the platform of ABAQUS to analyze the change of stress amplitude (the difference between the stress at the maximum loads and the stress without loads) at the areas where the orthotropic plate of steel box girder are prone to fatigue cracking under the conditions of no supporting bars and with supporting bars. The comparisons show that the experimental results are in good agreement with the finite element simulation results. The stress amplitude of U rib and T rib slots of orthotropic plate of steel box girder can be reduced by 40% 60% with the setting of the supporting bar, and the reduced proportion of stress amplitude ( the ratio of the difference of stress amplitude without and with supporting bars to the stress amplitude without supporting bars) of individual position can be reduced by 70%. The stress amplitude of top mid span can be reduced by 20% 40% with the addition of the supporting bar, and the stress amplitude of individual position can be reduced by 50%. The finite element analysis results show that the closer to the supporting bar, the larger the reduced proportion of stress amplitude at slotting positions. With the increase of the diameter of the supporting bar, the reduced proportion of stress amplitude increases, but the increasing amplitude decreases gradually. The rational using of supporting bar can effectively reduce stress amplitude of fatigue cracking-prone areas of the orthotropic plate of steel box girder, which can reduce the occurrence of fatigue failure of the orthotropic plate of steel box girder and improve its fatigue life at low cost.