Condition assessment of a prestressed concrete girder and slab bridge for increased axle loadings

Abstract

Our daily lives are becoming more dependent on civil infrastructure, including bridges, buildings, offshore structures, etc. Much of the existing infrastructure in India has been in service for many years. These structures continue to be in use, despite aging and associated damage. Hence, condition monitoring of these structures to provide necessary maintenance has become critical. The Indian Railway had requirement of increased freight haulage on the iron ore routes of various zonal railways. The Railway Board hence desired to undertake pilot project for operation of heavy axle freight wagons loaded upto 22.86 ton per axle. This proposed alteration may subject the bridges to higher tractive effort / braking forces (due to high power locos) together with higher axle loads. This proposed increase in load is acceptable only based on the available load capacity of the existing railway bridges. In this connection, condition assessment of a prestressed concrete slab bridge in service was carried out by adopting appropriate methodologies for instrumentation, testing and measurement. This paper describes the details of instrumentation adopted, various static and dynamic tests carried out and measurements taken during the investigation of the prestressed concrete slab bridge and also presents the results of the experimental investigation.