Natural corrosion effects on prestressed beams failure modes

Research carried out on the load-bearing capacity of naturally corroded beams in laboratory tests and existing structures is presented and analysed. Load tests were performed on short span pretensioned beams that experienced corrosion under service loads in two different industrial environments for 25 years. Prestressed beams from a decommissioned bridge after 40 years of service life with chloride attack were tested to failure. Different failure modes are analyzed using non linear finite element (NLFE) modelling and limit state models. Flexural and shear-bond failure are shown and analysed for prestressed beams with shear reinforcement. The results show that flexural failures can be predicted with simple resistance models and an estimate of the maximum cross-section loss. Lab tests show that bond-shear failure must be considered in corroded prestressed beams; these have been analysed by a NLFE model, but models for the bond deterioration and this structural limit state are not yet available.