Enz viaduct: a 1044 m long prestressed concrete box girder bridge

Abstract

This brief article describes the design and construction of the 1044m long Enz viaduct, which is a prestressed concrete box girder bridge carrying the railway over the Enz river about 25m before Stuttgart. It consists of 18 spans of 58m each, and the maximum height above the valley is 47m. The bridge is straight, with a gradient which has a change in longitudinal inclination from -0.15% to +1.2434%. A continuous girder with a depth of only 4.75m and with piers only 3.0m instead of 3.5m makes the bridge slenderer and more aesthetically pleasing. The girder is divided into three equal 348m spans, to aid replacement should this ever become necessary. The horizontal forces from trains braking and accelerating are transmitted to the abutments (axis 0 and 18). There, the forces are carried to the ground via hydraulic dampers. The bridge is fixed to piers no 7-11. This group of 5 piers holds the bridge in position even if braking occurs many times. These piers should also be able to take the whole braking force should the dampers ever fail. The bridge was built by incremental launching. The three continuous girders were fixed together during launching, and only divided into three afterwards. The French title of this article is: Viaduc de l'Enz: un pont en poutre-caisson en beton precontraint. The German title of this article is: Enztalbruecke: eine 1044 m lange Spannbeton- Hohlkastenbruecke. For the covering abstract of the conference see IRRD 851274.