中小跨径桥梁监测预警关键技术研究

Key Technology of Structural Health Monitoring of Short and Medium Span Bridges

中小跨径桥梁在我国桥梁总数中占比将近90%,随着桥龄的增加,结构的技术状况日益恶化。研发适用于中小跨径桥梁的健康监测技术已成为社会关注的重要问题。在分析了上部结构型式、活荷载作用下主梁位移占比、活荷载作用时间等影响中小跨径桥梁安全耐久的因素基础上,确定了以桥梁跨中动挠度作为中小跨径桥梁监测的关键指标,并提出了采样频率和精度等要求。以某在役中小跨径桥梁为对象基于毫米波雷达技术开展了动挠度监测试点应用,利用均值滤波算法实现了活载挠度与温度挠度的分离,结合监测统计值确定了分级报警阈值设定方案。通过试点监测案例,表明基于动挠度监测技术在中小跨径桥梁中具有显著的应用优势。

Short and medium span bridges account for nearly 90%of the total number of bridges in China and are now deteriorating due to aging.Therefore,it is becoming an important social concern to develop health monitoring systems for short and medium span bridges.In the paper,based on the analysis of the factors affecting the safety and durability of short and medium span bridges,such as superstructure type,the proportion of live load,the action time of live load,the mid-span dynamic deflection is determined as the key index to monitor short and medium span bridges,and the requirements of sampling frequency and accuracy are put forward.Based on millimeter-wave radar technology,apilot application of dynamic deflection monitoring is carried out for a short and medium span bridge that in-service.The mean filter algorithm is used to separate live load deflection from temperature deflection,and a hierarchical alarm threshold setting scheme is determined based on monitoring statistics.Through the pilot monitoring cases,it shows that the dynamic deflection monitoring technology has significant application advantages for short and medium span bridges.