The Dutch road infrastructure contains a large number of concrete bridges and viaducts. Malfunction of these bridges and viaducts has large financial consequences. To avoid malfunctions of bridges, bridges need to be inspected frequently and actions should be taken when required. The reliability of the inspections of the health of a bridge could be increased by monitoring the deflections and/or the vibrations of the bridge. The main idea of a Structural Health Monitoring system is that degradation of a bridge results in detectable changes in the deflections and in the modal properties of the bridge. The results of data-driven modal calculations of an existing concrete bridge have been compared with the results of Finite Element modal calculations of this bridge to investigate whether this comparison can be used to predict damage in the bridge. The effect of fatigue and localized corrosion damage on the deflections of a Reinforced Concrete beam was investigated by laboratory tests. The effect of fatigue and localized corrosion damage on the deflections and on the first natural frequency of a Reinforced Concrete beam was predicted by Finite Element calculations and probabilistic calculations. It was concluded from the tests and from the calculations that deflections and natural frequencies cannot be used as indicator for fatigue damage in concrete bridges.@en

During the service-life of Reinforced Concrete (RC) bridges, the deflections and the natural frequencies of the bridge change. It was considered that damage in a RC bridge results in changes in the deflections and in the natural frequencies of the bridge. Since these changes could be obtained by a Structural Health Monitoring system, the popularity of such system is increasing. It is, however, uncertain how the deflections and the natural frequencies of RC bridges change during their total service-life. It is also uncertain how damage in a RC bridge changes the deflections and the natural frequencies of the bridge. To obtain information about changes in the deflections of a RC beam during its total service-life, laboratory tests have been conducted. 24 RC beams have been loaded dynamically in a four-point-bending configuration. The deflections of the RC beams have been measured from the first cycle until failure. To investigate the impact of corrosion in the reinforcing bar on the fatigue failure mechanism of the RC beam, corrosion was simulated in the reinforcing bar of 12 of the 24 RC beams. The reinforcing bars of the other 12 RC beams were uncorroded. The setup of the tests and the deflections of the RC beams with and without corrosion in the reinforcing bar are presented in this paper.@en