A design method for prismatic prestressed continuous box girder bridges

Abstract

Prestressed concrete is one of the most difficult building materials to design due to many reasons such as number of different solutions available for the same problem and the time dependent changes that take place. When used for continuous box girder bridges, there are added problems associated with secondary moments. In this paper, a straight forward design method has been presented that localises the iterations involved in the design process as much as possible so that the calculations involved can be minimised. The guidelines to determine the cross sectional dimensions has also been discussed. A complete design example has been presented for a three span continuous bridge. A simple method for modelling a box girder as a grillage of beams also has been presented.