Corrosion effects on the capacity and ductility of concrete half-joint bridges

Monitoring and evaluating the deterioration of structures is one of the most pressing challenges of the last decades. Bridges and overpasses represent a significant percentage of infrastructures requiring ongoing maintenance and monitoring. In this scenario, a typical static solution used in the last century is the Gerber half-joint, obtained by reducing the cross-section of a beam end, supported by the nib of the adjacent beam or abutment. The particular geometry gives many benefits. However, at the same time, it is the origin of damages and failure due to the difficulty to access for inspections, and the proneness to corrosion phenomena. This study estimates the effect of corrosion on the capacity and ductility of two case studies: a half-joint tested by Desnerk et al. used for model calibration and a real-case half-joint. The author simulated an increasing level of corrosion in the two case studies by reducing the cross-section of the re-bars and modifying the ductility of steel. The analyses showed different behaviour in the two case studies. While the first exhibited a significant reduction of capacity and ductility, the real-case half joint did not show a manifest capacity reduction, still, accompanied by minor embrittlement of the response.