Grafton Bridge

:"For the bridge in Grafton, NSW, see "Grafton Bridge, NSW."

Grafton Bridge is a road bridge spanning Grafton Gully in Auckland City, New Zealand. Built of reinforced concrete almost 100 years ago, it connects the Auckland CBD with the Grafton suburb. Grafton Bridge spans about 97.6 metres (320 feet), rises 25.6 metres (84 feet) above the abutments and to a height of around 43 metres (142 feet) over the Grafton Gully.

The bridge is on the NZ Historic Places listing and the IPENZ Engineering Heritage Register. In a 2006 poll amongst 600 alumni of the University of Auckland School of Engineering, the bridge placed 3rd on the list of New Zealands engineering achievements, after the Manapouri Power Station and the "Black Magic".

Function

Overview

The bridge carries one traffic lane in each direction as well as footpaths on either side. At the moment (late 2006), all lanes are still open for all normal road traffic, though the bridge will soon become a bus priority route on the Central Connector. The footpaths are covered with an aesthetically curved glass screen, which serves to prevent people from falling or jumping off the bridge as well as providing unobstrusive weather cover (the bridge already had suicide prevention barriers from 1992 to 1996, but after the removal, suicide rates on the bridge jumped five-fold, leading to a quiet re-installation in 2002). ["Effectiveness of barriers at suicide jumping sites" - Beautrais, A L - "Australian & New Zealand Journal of Psychiatry" 35(5):557-62, Oct 2001]

Transit corridor

The bridge in 2007 carried around 13,000 vehicles per day, most of them through traffic. ["Get Moving: Your traffc questions" - "The New Zealand Herald", Tuesday 17 July 2007, Page A8] In the future, Auckland City plans to use Grafton Bridge as a major part of the new Central Connector, to connect downtown Auckland and the commercial-centre suburb of Newmarket with improved bus services. This will mean that from 7am to 7pm on weekdays, normal traffic will be banned to allow up to 1,500 daily bus trips to get preference." [http://www.nzherald.co.nz/search/story.cfm?storyid=000700C0-DF42-1520-91D183027AF1010F Revamping Grafton Bridge to cost $7.3m] " - "The New Zealand Herald", Tuesday 03 October 2006] This will effectively make Grafton Bridge a bus lane, operating like other bus lanes in the city. For this project, somewhat controversial due to the interruption of the direct car connection to Grafton, the bridge is being tested and in 2008, strengthened, [ [http://www.nzherald.co.nz/location/story.cfm?l_id=117&objectid=10449239 "Get Moving: Car travel to be restricted over Grafton Bridge"] - "The New Zealand Herald", Tuesday 03 July 2007] .

The modifications, which for structural reasons will close the bridge to all but cyclist and pedestrian traffic for about 14 months starting October 2008, ["St John aim to avoid Grafton jams" - "The New Zealand Herald", Wednesday 01 october 2008, Page A7] are to ensure that in the future, the weight limit can be raised from 13 tons to 40 tons, allowing the heavier buses to cross. Costs are expected to be around $7.3 million for new anchors at the bridge's two main piers, carbon fibre wrapping around various steelwork and improvements to foothpaths.

History

The bridge was built in 1910 and was the third bridge to cross Grafton Gully. The first two bridges (built 1884 & 1905) were pedestrian bridges which ran from the bottom of St Martins Lane to Grafton Road (the current bridge connects Karangahape Road and Grafton Road). Championed by the Mayor Sir Arthur Myers, it cost £31,918, resulting in it being called "Myers' Folly" by many at the time, but was also seen to symbolise a commitment to a 'Greater Auckland' as well as state leadership in technology development.

Built of reinforced concrete by the Ferro-Concrete Company of Australasia Ltd, it is believed to have been the biggest arch bridge span of that type existing at that time. In order to dispel doubts about the strength of the still relatively untested type of construction, at the opening in April 1910 two steam rollers were driven across it. This lack of trust had also led to a stipulation in the original construction contract that no progress payments should be made, causing the construction company to go into bankruptcy, with the bridge having to be completed by the city. [ [http://www.ipenz.org.nz/heritage/itemdetail.cfm?itemid=135 Grafton Bridge] (from the IPENZ Engineering Heritage Website. Accessed 2008-10-08.)]

Symonds Street Cemetery, a historic Auckland cemetery with many old and imposing (though often crumbling) gravestones is under and around the bridge on the steep inner-city side bank of the Grafton Gully.

References

External links

* [http://www.historic.org.nz/Register/ListingDetail.asp?RID=16&sm= Grafton Bridge] (database entry in the Historic Places Register)
* [http://www.ipenz.org.nz/heritage/itemdetail.cfm?itemid=135 Grafton Bridge] (database entry in the IPENZ Engineering Register)