Deformation monitoring and numerical simulation of prestressed concrete beam with local corrosion and fracture of prestressed steel

To understand the influence of corrosion and fracturing of prestressed steel on structural deformation, accelerated corrosion testing was carried out using a self-made test beam and applying DC power. Distributed optical fibre sensing technology based on pulse prepumped Brillouin optical time-domain analysis (PPP-BOTDA) was used to monitor the deformation of the prestressed concrete beam in the process of corrosion and fracture in real time. The finite-element model of local corrosion fracture of prestressed steel is established, and the monitoring results are verified based on various corrosion fracture simulation methods. The results show that when the sensing optical fibre pasted on the beam is less than 150 mm from the prestressed steel, the significant change of concrete strain when the steel breaks can be monitored and the fracture location can be determined at the same time. However, when the distance is greater than 150 mm, the change in monitoring data with the strain is not obvious. The distributed optical fibre sensing technology has high monitoring efficiency and abundant measurement data, and the underwater environment does not affect the transmission of monitoring data. This technology is applicable to the deformation monitoring of large prestressed concrete structures and could be widely used in practical engineering.