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 in 1910, 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 Black Magic . Since 2009, the bridge forms a core part of the Central Connector public transport route between the Auckland CBD and Newmarket, and is closed to private vehicles during daytime hours.

History
Designed by engineer R. F. Moore, and its construction supervised by the city's engineer, W. E. Bush, 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). These cable-stay bridges were comparatively unstable, and it was said of one that police were stationed on the bridge after rugby matches to ensure rowdy crowds did not cause it to collapse by jumping or stamping on it. The new bridge was championed by the Mayor Arthur Myers (who advocated for it to be twice as wide as it was eventually built). Even in its narrower form, it was to 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. It utilises large 'false piers' at each end which give the appearance of strength in the classical masonry style, but are actually not required to be anywhere as massive. 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. This also added to the final costs, which were around £33,000 Symonds Street Cemetery, an 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.

Function

Overview
The bridge carries one traffic lane in each direction as well as footpaths on either side. The bridge was closed for reinforcement works between late 2008 and October 2009. In October 2009 it was reopened by Mayor John Banks to 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 unobtrusive weather cover (the bridge already had suicide prevention barriers from 1992 to 1996 (and extra safety fencing from as early as 1936), but after the removal, suicide rates on the bridge jumped fivefold, leading to a quiet re-installation in 2002). There have been no suicides from the bridge since then as of 2009, and the feature has been called an example of best practice of preventing such acts.

Transit corridor
The bridge in 2007 carried around 13,000 vehicles per day, most of them through traffic. Starting in 2009, Auckland City plans uses 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 resulted in the bridge becoming a 7am to 7pm bus lane, with normal traffic banned to allow up to 1,500 daily bus trips (and up to 65,000 passengers) to get preference. For this project, somewhat controversial due to the interruption of the direct car connection to Grafton, the bridge was tested and in 2008-2009, strengthened. The modifications, which for structural reasons closed the bridge to all but cyclist and pedestrian traffic starting October 2008, 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. The works also ensured that the bridge will now be able to withstand a 1000-year earthquake. The bridge had been found to be in good shape, despite around 2,800 primarily minor faults having been found during the upgrade, and only two pieces of reinforcing steel had to be replaced. Costs were originally 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. In October 2009, the bridge was reopened ahead of schedule, the works having cost $6.9 million. However, the full intended level of bus services did not immediately use the bridge, as the Central Connector project itself was not fully finished at that stage. Compliance with the bus lane regulations was low initially, and after issuing warnings only for an initial period, Auckland City Council eventually began issuing infringement notices, ticketing 831 offenders during the first five days.