Experience in Monitoring the State of the Load-Bearing Structure of Prestressed Concrete Bridge to Extend Its Operation

Abstract The paper deals with assessing and monitoring the structural behaviour of the load-bearing structure of a road bridge over the railway in Bratislava. The prestressed concrete bridge is heavily damaged by corrosion of the prestressing tendons and steel reinforcement. The extensive damage was the reason why it was not effective to repair and strengthen the bridge. Because the bridge is the only link between the city and the industrial area, and the preparation of a new bridge project requires time, it is necessary to keep the bridge in operation for a while. The monitoring was designed based on the results of a detailed diagnostic survey, load tests, and assessment of the load-bearing capacity of the bridge. The monitoring includes long-term measurement of deformations with additional load test, measurement of the dynamic properties of the bridge, and detailed visual controls of the most damaged parts of the bridge at regular time intervals. The bridge has been under surveillance since 2020, with no further significant deterioration of the structural behaviour, which was achieved by several interventions in the bridge, i.e., repair of the bridge surfacing, including waterproof insulation, and creation of a single traffic lane with a pendulum traffic.