A9 Gleinalm Tunnel portals

The twin-carriageway upgrade of the Gleinalm Tunnel section of Austria's A9 motorway involves the construction of two impressive portals at the ends of the tunnel. The tunnel cross-section is rectangular, but as they stretch away from the tunnel proper the inside and outside walls gradually assume a pronounced outward lean. The clear width of the tunnel portal and the inclination of the top slabs also increase toward the front. Innumerable kinks give the portals their unique profile.

Length of northern portal including ventilation separating wall: approx. 100.00 m
Length of southern portal including ventilation separating wall: approx. 87.00 m
Clear propping height of top slab: up to 12.80 m
Angle of inclination of outside walls: from vertical to 17 ° outward lean

cover photo (c) fasch&fuchs.ZT