e-mosty June 2017: Osman Gazi B. US Suspension. Hålogaland B. e-mosty June 2017: Suspension Bridges | Page 16

3.3 Cable system installation
3.3.1 Main Cables
The two main cables have a diameter of 475mm in
the main span; 484mm at Karistranda and 492mm at
Øyjord back span. Main cables are made up of 40 wire
strands, each consisting of 127 steel wires each with
5.96mm diameter, additional back span cable strands
consisting of 91 wires with 5.96mm diameter, with 2
additional strands on the Karistranda side and 4
additional strands on the Øyjord side. There are a
total of 18,300 km of steel wires. Each cable weighs
2,010 tonnes.
Figure 18 ↑: Main cable strands and additional back span strand
Figure 19 ←: Main cable and strand section
The A-shape of the towers influences how the cable
system is installed. To obtain the correct shape, a
special construction sequence is required allowing the
two main cables to hang vertically during installation.
The splay saddles and the tower top saddles were
mounted.
Temporary constructions such as tower top platforms,
portal frames and the working platform (catwalk)
were installed. The catwalk was designed as three
separate catwalks (not as continuous system), and it
was designed to follow the shape of the main cable
during the construction period.
Main cables are made from PPWS (Prefabricated
parallel wire strands). The strands were fabricated in
the factory, with a socket at each end, cut-to-length,
coiled to drums, and then transported to the site.
Approximate weight of one drum with strand was 54
tonnes.
The two main cables were formed by pulling the
strands from Øyjord side to Karistranda side, using
the hauling system.
Video: Strand pulling over the saddle
2/2017