Design Concept of Pre-Stressed Balanced Cantilever Segmental Bridge

Abstract

Bridges are constructed by cantilever method to cross geological critical areas such as valleys, rivers, and in heavy traffic areas for the easy flow of vehicles where shoring may become costly or even may not be able to be adopted. The construction is carried out segment by segment on either side of the pier above the ground level and so it can also be called as segmental balanced cantilever bridges. Spans of 80 to 150m are favored for bridges with prestressed concrete box girder decks built by the cantilever method. However, this method can be used for spans up to 200m in common widths without major problems. This paper is going to explain a design procedure for segmental prestressing along with an example which was solved using IRC6-2014 and IRC112-2011. The concept of simplified frame analysis is adopted for transverse analysis, and a line beam modeling is adopted for longitudinal analysis. For the calculation of prestressing forces, Magnels graphical method is used.