The Grande Ravine viaduct is integrated in a project comprising 34km of 2×2 expressway lanes, the so-called “Route des Tamarins”. This outstanding structure spans the breccia of the Grande Ravine, whose vertiginous dimensions are approximately 300m in width and 170m in depth.


The Grande Ravine Viaduct consists of a metal deck with a 288m long orthotropic slab hinged on two concrete braces tilted 19° with respect to the horizontal. The braces are embedded at the bottom of the counterweight abutments and held at the top by rods located inside the deck. Structurally, it is a bridge with a limited and controlled arch effect.


To meet the structural requirements, high elastic limit steels and high-performance concretes are employed. The structure is designed to resist cyclone winds capable of attaining peak speeds of 270km/h. The study of these winds was performed in a wind tunnel at the CSTB.


The braces are constructed by successive coffer dams and held on top by temporary rods during the “launching” of the deck up to its half-length from each bank.




setec, as part of the consortium with Spielmann, was awarded the design and works project management contract.


Key information

Client : Reunion Region

Design and Works PM JV partners : setec, Spielmann

Period : 2002-2009

©Région Réunion

In a Nutshell

270km/h cyclone winds speed
19° inclination of braces
288mtotal length

Large Displacement studies 

Dynamic and static models are carried out with the use of setec tpi’s in-house software, PYTHAGORE, comprising beam elements (deck, braces) and shell elements (abutments). The calculations consider the construction phasing approach, the ground brackets and the scientific (ideal) creep with creep brackets. The computational chain integrates a check for buckling in large dimensions, a check for “sailing” in the metal sections, and a check for the braces in a broken section.