Design
On completion of construction, the (260 m/853 ft) main span of the Gateway Bridge was a world record for a prestressed concrete free cantilever bridge. It held this record for over 15 years. The box girder is still the largest prestressed concrete, single box in the world, measuring 15 m (49 ft) deep at the pier, with a box width of 12 m (39 ft) and an overall deck width of the 6 lanes of 22 m (72 ft).
The bridge owes its distinctive shape to air traffic requirements restricting its height to under 80 metres (260 ft) above sea level (all features of the bridge including light poles) coupled with shipping needs requiring a navigational clearance of 55 metres (180 ft).
The bridge has six lanes (three in each direction). The bridge was financed by funds borrowed by the Queensland Government, and as a result, users of the bridge pay a toll on the southern side of the Brisbane River. The Bridge is operated and maintained by Queensland Motorways, which is a Queensland Government-owned enterprise.
The total length is 1,627 metres (5,337 ft). This is divided into a southern approach of 376 metres (1,234 ft), a northern approach of 731 metres (2,398 ft) and the three central spans of 520 metres (1,706 ft). The main span is 260 metres (853 ft) long by 64.5 metres (212 ft) high, which is equivalent to a 20-storey building. A total of 150,000 tonnes (165,000 short tons) of concrete was used to construct the bridge.
The original design did not include a safety fence to prevent suicide attempts and base jumping. Three-metre high safety fences attached to the top of the concrete traffic barrier were later installed to prevent these incidents occurring. Anti-climbing screens are part of the second bridge's security features.
Read more about this topic: Sir Leo Hielscher Bridges
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