Design of Haunched Single Span Bridges

Abstract

A novel method for the design of variable depth single span bridges having maximum depth at the ends and minimum depth at midspan is presented. These bridges are intended to be used for long span river crossings or highway overpasses, where only a single span is required, and the vertical clearance below needs to be maximized, and/or an aesthetically pleasing graceful shape is desired. The design is made possible by “fixing” the ends to “lock-in” negative moments, so that the positive moments at midspan are greatly reduced, and a shallow section may to be used. The method is developed and presented in two parts. The first part discusses and unifies the behavior of three very famous bridges (the Luzancy Bridge in France designed by Eugène Freyssinet, the Gänstor Bridge in Germany designed by Ulrich Finsterwalder, and the Pinzano Bridge in Italy designed by Silvano Zorzi). The second part describes the method in detail by virtue of a complete design example. Application of the method to other bridges is included, and abutment treatments to enhance the visual qualities are presented. This innovative bridge type will be of interest to those looking for a practical and elegant new bridge solution for long span bridges.