Tasman Bridge

Tasman Bridge
File:Tasman Bridge Dusk.jpg
Coordinates
Carries	Tasman Highway
Crosses	Derwent River, Southern rail line
Locale	Hobart, Tasmania
Maintained by	Department of Infrastructure, Energy and Resources
Characteristics
Design	Prestressed concrete Girder
Total length	1,395 metres (4,576 ft)
Width	17.5 metres (57'-2 ft)
Height	60.5 metres(197 ft)
Clearance below	46 metres (150 ft)
History
Construction begin	May 1960
Construction end	23 December 1964
Statistics
Daily traffic	67,000

The Tasman Bridge is a five-lane bridge crossing the Derwent River, near the CBD of Hobart, Tasmania. The bridge has a total length (including approaches) of 1,396 metres (4,576 ft). As part of the Tasman Highway, it provides the main traffic route from the CBD (on the western shore) to the eastern shore. It has a pedestrian foot way on each side, but no dedicated lane for bicycles. However, steps to the pedestrian foot way have recently been replaced with on-ramps.

History

In the 1950s with the development of the Eastern shore, it was decided to build a larger bridge; the old Hobart Bridge faced increasing difficulty in managing the larger volumes of traffic that came with development, and constantly raising the lift span for shipping was disruptive. The total cost of the new bridge in conjunction with approach ramps and Lindisfarne Interchange was in the area of £7 million. Construction commenced in May 1960 and the bridge was first opened to traffic (2 lanes only) on 18 August 1964. The bridge was completed with all four lanes operational on 23 December 1964. It was officially opened on 18 March 1965 by Prince Henry, Duke of Gloucester. During peak construction a labour force of over 400 men was employed on site.

Disaster

Main article: Tasman Bridge disaster

On Sunday 5 January 1975, at 9:27 p.m. Australian Eastern Summer Time, the Tasman Bridge was struck by the bulk ore carrier Lake Illawarra, bound for the Electrolytic Zinc Company with a cargo of 10,000 tons of zinc concentrate. It caused two pylons and three sections of concrete decking, totaling 127 metres (417 ft), to fall from the bridge and sink the ship. Seven of the ship's crewmen were killed, and five motorists died when four cars drove over the collapsed sections before the traffic was stopped. A major press shot showed a Holden Monaro HQ GTS, which was owned by Frank and Sylvia Manley, along with an older EK Holden station wagon, driven by a local man Mr. Murray Ling, perched balancing on the ledge.

The depth of the river at this point (35 metres (115 ft) is such that the wreck of Lake Illawarra still lies on the bottom, with concrete slab on top of it, without presenting a navigation hazard to smaller vessels.

The breakage of an important arterial link isolated the residents in Hobart’s eastern suburbs – the relatively short drive across the Tasman Bridge to the city suddenly became a 50 kilometre (31 mi) journey via the estuary's next bridge at Bridgewater. The only other vehicular crossing within Hobart after the bridge collapsed was the Risdon Punt, a cable ferry which crossed the river from East Risdon and Risdon, some five kilometres upstream from the bridge. However, it was totally inadequate, carrying only eight cars on each crossing, and although ferries provided a service across the Derwent River, it was not until December 1975 that a two lane, 788m long Bailey bridge was opened to traffic, thereby restoring some connectivity.

Tasman Bridge from Mount Nelson

The separation of Hobart saw an immediate surge in the small and limited ferry service then operating across the river. In a primary position to provide a service were the two ships of Robert Clifford, a Tasmanian mariner. He had introduced the locally-built ferries Matthew Brady and James McCabe to the river crossing, from the Central Business District of Hobart to the eastern shore, shortly before the collision. These two ships were soon joined by the Cartela, a wooden vessel of 1912 vintage, and other ships, including Sydney Harbour ferries, pressed into service by the Tasmanian Government, to ferry thousands of commuters across the river.

Following successful rebuilding of the Bridge, Clifford's organisation saw the ferry traffic fade quickly, but by then he had diversified into further building of ships..

On 20 June 2007, a crane toppled whilst carrying out works on the bridge, and precariously hung for a number of hours off the side of the barriers.

Panorama of the Tasman Bridge at night.

Reconstruction

Entering the bridge from the eastern shore

Reconstruction of the Tasman Bridge commenced in October 1975. An important factor of the reconstruction is the improved safety measures. Some examples:

• Large vessels passing beneath the bridge must now do so slightly to the west of the original main navigation span.
• Personnel controlling ships (or harbor pilots) must be trained and then cleared for using the special laser lighthouse that indicates by colours whether the ship must be steered left or right to regain the centre line.
• All road traffic is now halted whilst large vessels transit beneath the bridge.

On top of the new safety measures implemented, the bridge was further upgraded to hold a fifth lane. This upgrade included the construction of a lane management system which would enable the new middle lane to function as a reversible lane. The system consists of a traffic light system and a sign above each lane, pictured right. The signs, in conjunction with the traffic light system, employ a pulley system to periodically pull the signs over their appropriate lanes.

The middle lane points towards the city side (or western shore) during a.m. peak hours and points back towards the eastern shore during p.m. peak hours. The lane generally points towards the eastern shore during non-peak hours.

The Tasman Bridge repair took two years and cost approximately $44 million. The bridge officially reopened on 8 October 1977.

Replacement

In 2010, Clarence Alderman Richard James stated that it was time to consider the replacement of the Tasman Bridge with a new bridge of suspension or cable stay design citing that the current bridge was facing a greatly reduced lifespan due to damage to the internal steel structure caused by the Tasman Bridge disaster. Richard James has suggested a timeframe of no more than 20 years.

Gallery

• Tasman-under-from-east-shore.jpg

  View of the bridge from the eastern shore.

• Tasman-bridge-from-south.jpg

  Looking towards the Tasman Bridge from Montagu Bay.

• NS14TasmanBridge.JPG

  Dinghy and the bridge.

• Tasman-bridge-fixed-span.jpg

  The repaired bridge span

• Tasman Bridge Hobart1.jpg

  The view of the Bridge from Mount Wellington

• Derwent River 013.jpg

  A view of the bridge from the river

• 

  Tasman Bridge from the Western shore

See also

• List of disasters in Australia by death toll

References

• Reference: Lewis, Tom. By Derwent Divided. Darwin: Tall Stories, 1999.
• Ludeke, M. (2006) Ten Events Shaping Tasmania's History. Hobart: Ludeke Publishing.

External links

• Live webcam view of Hobart including the Tasman Bridge
• Traffic camera view of the Tasman Bridge
• Archival photographs of construction of the Tasman Bridge: page 1, page 2.
• 1995 article about Tasman Bridge safety
• Hobart To Tasman Bridge 1938-2000
• Tasman Bridge at Structurae