Inspection methods and precautions for common structural diseases of simply supported beam bridges
简支梁桥常见结构病害巡检方法及注意事项

摘要

面向沿海重载矿卡与氯盐耦合环境下的30m装配式PC简支T梁桥，构建“无人机高清拍照+人工复测”两步巡检体系，对弯曲、剪切、网状收缩裂缝及混凝土剥落四类表观缺陷进行运营天窗级快速筛查；U-Net语义分割实现0.1mm裂缝92%召回，引入裂缝密度ρ与氯盐修正阈值，现场验证数据误差<5%，为后续BIM挂接和养护资金精准投放提供可复用的量化模型。

Abstract

For a 30-meter prefabricated PC simply supported T-beam bridge under the coupling environment of heavy-duty mining trucks and chlorides along the coast, a two-step inspection system of "drone high-definition photography + manual re-inspection" is constructed to conduct rapid screening of four types of apparent defects, namely bending, shearing, network shrinkage cracks and concrete spalling, at the operational window level. U-Net semantic segmentation achieves 92% recall of 0.1mm cracks, introduces crack density ρ and chloride salt to correct the threshold, and the on-site verification data error is less than 5%, providing a reusable quantitative model for subsequent BIM connection and precise allocation of maintenance funds.