EXPERIMENTAL INVESTIGATION ON THE MECHANICAL BEHAVIOR OF CORRODED PRETENSIONED BEAMS

Corrosion phenomena and related effects, such as size reduction in both rebars and strands, bond decay at steel-concrete interface, and cracking in the surrounding concrete, are particularly critical in prestressed-concrete members, not only for safety reasons, but also for their huge possible socio-economic effects, since this technique has been used for the last 50 years in the majority of viaducts and bridges built in many countries like Italy. In order to evaluate the influence that corrosion has on prestressed pretensioned beams, a number of tests has been carried out in the Laboratory of the University of Rome "Tor Vergata". Nine prestressed beams (section size 200x300; total length 3000 mm; clear span 2700 mm) were first subjected to artificial corrosion, to obtain different damage levels, and then were tested in 4-point bending. The results clearly show the sizable effects that corrosion has on the ultimate capacity (that is significantly reduced), on the failure mode and on the structural response, that turns from ductile to brittle.