The Sydney Harbour Bridge, Sydney, Australia
The total weight of the bridge is 52,800 tonnes, and six million hand-driven rivets hold the bridge together. The rivets were made at the Park Bridge Ironworks in Lancashire England.
The two pairs of pylons at each end are about 89 m (276 feet) high and are made of concrete and granite. Abutments, which support the ends of the bridge, are contained at the base of the pylons. They prevent the bridge from stretching or compressing due to temperature variations. Otherwise, the pylons serve no structural purpose and are primarily to visually balance the bridge itself. They were originally not part of the design but were added later to allay concerns about structural integrity — ironically, as the pylons do not actually touch the bridge (except at road level). Although inserted into the designs for their aesthetic value, all four pylons have now been put to use: a museum and tourist centre with a lookout of the harbour is contained in the southeastern pylon.
The southwestern pylon is used by the New South Wales Roads and Traffic Authority (RTA) as a base for their CCTV cameras overlooking the bridge and the roads around that area. The two pylons on the north shore are now venting chimneys for fumes from the Sydney Harbour Tunnel. The RTA maintenance shed for the bridge is contained within the bottom of the southern pylon and the traffic management shed (tow trucks and safety vehicles used on the bridge) is contained in the bottom of the northern pylon.
[Source: Wikipedia]
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April 16th, 2007 at 2:42 pm
http://www.youtube.com/watch?v=4O8eCn-Pv5Y