The viaduct of Houffalize is located on the E25 motorway that links Utrecht to Genova (Genoa), between Liège and Bastogne, and it crosses the Eastern Ourthe's deep valley. It is long 369,6 meters whereas the reinforeced concreted arch's loading is 162 meters for a height of 60 meters. The arched viaduct of Houffalize is one of the greatest arches in the world together with the Eau rouge viaduct in Malmedy.
Its building started on May 6 1974 and ended up in June 14 1979. The total amount of the investments was BEF 422 millions. The viaduct is made of two identical bridges that are large 16 meters, one for each direction. Their lenght is 369,6 meters. Each one of the half viaducts is divided into fourteen isostatic spans whose loading is 26,40 meters. Each one of these spand is crossed by five prefabricated girders in prestressed concrete, that are equidistant, 3,60 meters away from each others. these girders carry permanent shuttering concrete slabs that carry the screed made with argex concrete. This screed is interrupted by expansion joints only. The viaduct's supports are in the rock and the central zone's are in the arch.
The arch has a loading of 162 meters and its top is about 60 meters over the depth of the valley.