裂缝宽度的提取及在桥梁承载力评估中的应用研究

Research on the extraction of crack width and its application in the evaluation of bridge bearing capacity

以旋翼无人飞机为工作平台搭载富士X-T20单反相机获取混凝土桥梁的裂缝图像,基于MATLAB编制桥梁裂缝图像处理程序,对桥梁裂缝形状进行识别。根据裂缝形状特征选取裂缝区域图像短轴的像素参数,基于修正后的解析度式计算出混凝土桥梁裂缝图像的最大宽度。本研究选取12张图像进行裂缝最大宽度计算,裂缝宽度识别平均相对误差为4.14%。根据裂缝宽度与桥梁承载能力之间的关系建立桥梁ANSYS模型,得到一系列裂缝宽度对应的桥梁承载力富余系数。混凝土桥梁的承载力富余系数为0时裂缝宽度达到0.6 mm,此时裂缝宽度已经远超规范值。发现承载力富余系数可作为混凝土桥梁结构在运营阶段的重点观测参数,对混凝土桥梁的长期安全监测具有指导意义。

The unmanned aerial vehicles with FUJIFILM X-T20 cameras were used for the imaging platform to got images of bridge cracks.Bridge crack shapes were identified by the bridge crack image processing program based on MATLAB.According to the shape feature,the short axis parameters of crack image area were selected as the parameters of resolution formula.The maximum crack width was calculated by revised resolution formula.Twelve images were selected to calculate the maximum crack width,and the average relative error of identifying crack width was 4.14%.According to the relationship between the crack width and the carrying capacity of the bridge,ANSYS model of the bridge was established to obtain the carrying capacity of the bridge corresponding to a series of crack widths.The crack width of concrete bridge is 0.6 mm when the excess coefficient of bearing rate is 0,with the crack width far exceeding the normal value.The excess coefficient of bearing capacity can be used as the key observation parameter of concrete bridge structure in the operation stage and it is of guiding significance to the long-term safety monitoring of concrete bridge.