Tamina Canyon Crossing

Structural Designer

Leonhardt, Andrä und Partner

Client Name

Tiefbauamt Kanton St. Gallen

Location

Bad Ragaz, Canton St. Gallen, Switzerland

PRINCIPAL CONTRACTOR
ARGE Taminabrücke c/o Strabag AG, Glattbrugg, J. Erni AG, Films Dorf, Mesierbau AG / Balzers

ARCHITECT
Volkhard Angelmaier
 
  Images: © TBA St Gallen

PROJECT DESCRIPTION

The bridge crosses the Tamina canyon 200m above the gorge. The arch and the superstructure create a continuous prestressed girder mainly forming the structural system. The 417m long superstructure is connected monolithically to the arch by inclined columns; the total length of the structure is 473m with abutments included. 

Judge's comment:

This is undoubtedly an outstanding engineering solution, and the judges were impressed by the elegance, clarity and economy of the design. The judges noted the efficiency of the structural system, as well as the beautiful way that the design integrates with its spectacular surroundings. This is a concrete arch design in the best traditions of Christian Menn and Robert Maillart, and the engineers have produced a world class and graceful design.

The judges liked the way that the open spandrel prop supports are inclined in a radial fan arrangement, and the high degree of transparency that has been achieved, with an attractive rhythm for the spans of the deck girder. This transparency is accentuated by the slenderness of the thin inclined props which is achieved by the use of meticulously detailed concrete hinges.

The two end props, which spring from the ends of the arch, imposing both physical and visual weight at these points to good effect, work as part of an integral framing system with the slightly deeper end spans of the girder. These spans can therefore be longer, thus avoiding the need for additional foundations at the sensitive upper slopes of the valley. So the bridge stands on just four foundations, reducing construction uncertainty and maximising the economy of the scheme.