Formulation of repair methodology for corrosion damaged exterior girders of Sardar and Gandhi bridge across river Sabarmati at Ahmedabad
The Sabarmati River Front Development Corporation Ltd. (SRFDCL), Ahmedabad has approached CSIR-Structural Engineering Research Centre (SERC), Chennai to assess the condition of two bridges namely Gandhi Bridge and Sardar Bridge and to formulate repair and rehabilitation strategies of distressed bridges. It has been observed that mainly due to water seepage caused by improper drainage system of the bridges lasting several years, some of the girders are severely corroded and the girder reinforcement is exposed. In view of this, a detailed analysis has been carried out by CSIR-SERC to assess the demand from dead load and live load. It has been found that the amount of reinforcement calculated from the analysis results is generally in close agreement with that report supplied by SRFDCL. Since the distress of the bridge girder is visually distinct and the report given by CECRI indicated that atleast 25% of the reinforcement are corroded, in the present study it has been attempted to formulate different strengthening strategies to provide additional strength against live load. The reason behind is that the dead load is already been acting on the girder and large deformation in the girder has not been observed, so there would be no reason to design the retrofit strategy to carry dead load also. A detailed procedure has been presented for surface treatment of the distressed girder and further retrofit and strengthening using additional reinforcement with anchored stirrups / additional CFRP plates. Finally, additional measures are given to minimise further distress to the bridge due to absence of proper maintenance
