e-mosty June 2017: Osman Gazi B. US Suspension. Hålogaland B. e-mosty June 2017: Suspension Bridges | Page 11

2.2 Towers
The towers are concrete A-frames. For a bridge with
more lanes, the “A” would be very wide and the
foundations would be very large – but this design is
ideal for a narrow structure. An H-shaped pylon
might appear too slender, given the tall height and
narrow width needed; and a central pylon is
impractical for a two-lane road.
Both towers stand the same height above the deck,
though the uneven road and terrain levels on either
side result in that one is 172.7m tall and the other is
167.1m.
Tower Karistranda
Bottom caisson at -31.0m
Top concrete in tower + 172.7m
Top tower house +179.1m
Total height 210m
Tower Øyjord
Bottom caisson -22.0m
Top concrete + 167.1m
Top tower house +173.5m
Total height 195.5 m
The tower design determined the layout of the rest
of the structure, especially the spatial arrangement
of the cables and hangers. The two main cables meet
at saddles on a narrow support on the top of the
towers, splaying out at the centre of the bridge. As a
result, the hangers are slightly inclined.
Each tower is topped with a “tower house”. It
provides extra protection to the cable and the
saddles. It is also an architectural feature, its internal
lighting will be the only strictly non-functional
feature on the bridge.
Figure 5 ↑: Tower rendering
Figure 6 ←: Tower leg
.
Figure 8: Rendering of the Tower House
Source: DISSING+WEITLING architecture
Figure 7: Tower House
2/2017