预应力混凝土结构广泛应用于公路和铁路桥梁建设中。受收缩徐变、荷载和温度等因素影响,混凝土在长期服役过程中可能会发生开裂,导致钢筋锈蚀或服役性能的劣化。已有的人工巡检和光纤传感等方法监测混凝土开裂时存在时效性和可靠性低等问题。基于漏磁效应和应力致磁化效应,研发了预应力混凝土结构开裂弱磁传感器并进行了可靠性分析和工程应用。结果表明,该弱磁传感器具有较高的灵敏度和可靠性,初步监测结果已得到大桥管理部门的证实,该系统可以实现对预应力混凝土开裂的实时、长期和自动化监测。

The prestressed concrete structure is widely used in the construction of highway and railway bridges. Under the influence of shrinkage and creep, load, and temperature, concrete may crack during long-term service, leading to deterioration of service performance such as steel corrosion. The existing methods such as manual inspection and fiber optic sensing have problems with low timeliness and reliability monitoring concrete cracking. Based on the magnetic leakage effect and stress induced magnetization effect, the author developed a weak magnetic sensor for cracking prestressed concrete structures and conducted reliability analysis and engineering applications. The results indicate that the weak magnetic sensor ha good sensitivity and reliability, and the preliminary monitoring results confirmed by the bridge management department. The system can achieve real-time, long-term, and automated monitoring of prestressed concrete cracking.