Sudden failure of reinforced concrete or prestressed concrete bridges and viaducts occurred in Italy in the last few years due to brittle failure of Gerber supports subjected to degradation of material such as corrosion of steel bars. The danger of sudden and brittle failure is often due to pitting corrosion, loss of bond in steel bars and concrete crushing. In this paper, the risk of failure of Gerber supports in service condition and at ultimate state under vertical and lateral loads was investigated focusing on the consequences of pitting corrosion and loss of bond in steel bars. A simplified strut-and-tie model was developed to predict flexural response of Gerber supports including effects of corrosion of steel bars, loss of bond and concrete crushing due to the biaxial state of stresses. Several experimental studies regarding the flexural behavior of RC beams with Gerber supports were collected to validate the proposed model. The topic of this research is of particular interest for existing bridges with Gerber supports to be retrofitted or strengthened for seismic verification.
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