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根据现场检查结果,虎门大桥辅航道桥箱梁顶板及梗腋部位出现较多纵向裂缝。为分析此类裂缝的形成原因,采用桥梁分析软件Midas Civil建立了混凝土箱梁平面框架模型,考虑横向及竖向预应力作用,对因桥梁铺装形式变化引起的截面梯度温度效应和车辆荷载效应进行深入地分析,对比分析原设计与现况条件下的箱梁截面各个关键点的应力情况。研究结果表明:桥面铺装形式变化和超重车效应均引起箱梁不利效应;现况条件下箱梁中心线顶板底部及梗腋处应力均明显大于原设计情况,且均超过了混凝土抗拉强度设计值。为保障桥梁结构安全,控制裂缝继续发展,应严格限制超55t重车通行。
According to the on-site inspection results, there were more longitudinal cracks in the roof and stem axillary parts of the Huqimen Bridge airside bridge girder. In order to analyze the cause of such cracks, the plane frame model of concrete box girder is established by the bridge analysis software Midas Civil. Considering the effect of transverse and vertical prestressing, the effect of cross-section gradient temperature and vehicle load effect In-depth analysis, comparative analysis of the original design and the current conditions of the box girder section of the key points of stress. The results show that both the deformation of deck pavement and the overweight vehicle effect cause the adverse effects of the box girder. The stress at the bottom and the stem of the roof of the box girder at the centerline of the box girder is significantly greater than that of the original design under current conditions, Intensity design value. In order to ensure the safety of the bridge structure and control the development of fractures, the passage of over 55t heavy vehicles should be strictly limited.