Stay Cables
The western tower, along with the first three deck segments, were built at the same time and completed in mid 1993. During construction the three deck segments were supported by scaffolding and then, when tower construction was completed, the first stay cables were installed.
The sub contractor responsible for the cable stays was Austress Freyssinet Pty Ltd.
The individual strands, 15.7mm in diameter, consist of seven galvanised steel wires waxed and covered in polyethylene.
The number of strands in each sheath varied - increasing in number from 25 to 74 towards the centre of the bridge.
12m lengths of polyethylene sheath were welded together on the deck and an initial wire strand drawn in.
The sheath and strand were then winched into place and the initial strand fixed into the anchor points and tensioned to its predetermined load. 3.
sheath and the drawing wheel.
The remaining strands were then individually drawn into place through the polyethylene sheath from the deck level using a drawing wheel.
After being secured in an adjustable anchorage point in the tower head, the strand was cut to length and fixed at deck level.
A hydraulic jack at the tower top was then used to set the final strand tension to match that of the initial strand. 1.3.8.
Initially the stay cables were subject to serious vibrations. Experimentation using heavy ropes tying the stay cables diagonally back to the deck reduced the problem.
The spring failure safety link shown below was added later.
From 2011 to 2013 major works were undertaken to replace the stabilising cables with hydraulic dampers.See stay cable maintenance
