Effect of External Posttensioning on Member Forces of Determinate Pratt Pattern Bridge Truss

Abstract- Transportation on land is the most common one among all the modes of transportation: may be on roads or railways. In India and abroad bridges have been built along roadways and railways in order to make the transportation system more efficient and economical. Some of them are steel truss bridges and majority of which are very old and have been designed as per the codal standards existing at the time of their construction. Problems with these truss bridges are that, they are deteriorated to such extents which are not able to resist the loads for which they are originally designed and/or they may not be able to match with the current loading and traffic requirements. Hence there is a need to strengthen these existing truss bridges. The method to be adopted for strengthening should be cheap and economical with minimum disturbance to the existing traffic. Even though there are different methods of strengthening o