Everything about The Auckland Harbour Bridge totally explained
The
Auckland Harbour Bridge is an eight-lane,
box truss motorway bridge over the
Waitemata Harbour, joining
Saint Marys Bay in
Auckland City with
Northcote in
North Shore City,
New Zealand. It has a total length of 1,020 m (3,348 feet), with a main span of 243.8 m, rising 43.27 m above high water allowing ships access to the deepwater port at the
Chelsea Sugar Refinery up harbour (nowadays one of the few remaining wharves needing such access west of the bridge). It is part of the
Auckland Northern Motorway running from the
Central Motorway Junction in downtown Auckland to
Orewa.
Construction
Background
Prior to construction of the bridge, the quickest way of getting from Auckland to the North Shore was via one of the regular passenger or vehicular ferries. By road, the shortest route was through
West Auckland via
Riverhead and
Albany, a distance of over 40 kilometres.
Initial structure
The bridge took four years to build and was opened on
May 30,
1959 by Prime Minister
Sidney Holland, with four lanes of traffic, two in each direction. Four men were killed during construction, and their names are recorded on a memorial plaque underneath the bridge at the Northcote end.
The bridge started out as a
toll bridge, with toll booths for both north and south-bound traffic located at the northern end. Tolls were originally 2/6 (25 cents) per car but were reduced to 2/- (20 cents) after 15 months of operation. Later, tolling was made south-bound only before being finally discontinued on
March 30,
1984, and the booths were removed. This was in line with political commitments that tolls would only be charged until the bridge's construction costs were paid off.
'Nippon clip-ons'
The bridge was originally built with four lanes for traffic. Owing to the rapid expansion of suburbs on the North Shore and increasing traffic levels it was necessary to increase the capacity of the bridge.
In 1969 two-lane box girder clip-on sections were added to each side, doubling the number of lanes from four to eight. The sections were manufactured by Japanese contractors (
Ishikawajima-Harima Heavy Industries Co., Ltd.), which led to the nickname 'Nippon clip-ons'. They have an expected lifetime of 50 years.
In 2006, it became public that cracks and signs of
material fatigue had been found in the clip-on lanes. Auckland City Council Transport Committee requested Transit New Zealand to investigate the future of the clip-on lanes as part of its 10-year plan. Transit noted in this context that the plan already includes some funding for bridge maintenance.
In May 2007, Transit New Zealand proposed a bylaw change to restrict trucks over 4.5 tonnes from using the outside lane on each clip-on. This is to reduce stress on the aging structure. This was later changed to a less strict bylaw introduced in July 2007 restricting only vehicles of 13 tonnes or more, based on the high level of voluntary compliance during the previous months.
In 2007, it was announced that NZ$ 45 million in maintenance work on the clip-on sections was being pulled ahead as part of good practice. However, in October 2007, a 2006 report from
Beca Group surfaced in the press, noting that the clip-ons were at risk of catastrophic, immediate failure in certain circumstances (such as a traffic jam trapping a large number of trucks on them). Transit New Zealand has noted that the situation described was extremely unlikely, and measures already implemented would prevent it from occurring.
Cycle- and footpaths
The bridge in its current form can only be used by motor vehicles (tourists can walk on the span via guided tours). In recent (2007) discussions about the future of the bridge, the addition of a cycle and footpath link between Auckland City and North Shore City has been mooted for the bridge. Transit New Zealand has noted that such a provision would cost between 20 and 40 million NZ$, but public support for such an addition to the bridge has been polled as being very high.
Cycle Action Auckland meanwhile notes that lower-cost options are available, and that a cycleway could relatively easily be included in the bridge strengthening works currently being planned for the clip-on structure.
Cycle Action Auckland has
created a webpage
showcasing the proposed walking / cycling solution and invites visitors to sign a petition supporting or opposing the proposal.
Traffic management
A "tidal flow" system is in place where the traffic direction of two of the centre lanes is changed in order to provide an additional lane for peak period traffic. During the morning rush, five of the eight lanes are allocated to southbound traffic heading towards Auckland. This situation is reversed in the afternoon, when five lanes are allocated to northbound traffic. At all other times of the day the lanes are split evenly, and peaks also have grown increasingly evenly distributed (for example whereas in previous decades (as late as 1991), there was often a higher than 3:1 difference in directional traffic, this has now (2006) dropped to around 1.6:1). The bridge has an estimated vehicle capacity of 180,000 per day, and in 2006 had an average volume of 168,754 vehicles per day (up from 122,000 in 1991).
Several projects either side of the bridge are also currently (2007) underway or planned to ensure that the motorway capacity on both sides matches that of the peak time capacity of the bridge (a factor which is considered by some to be more of a bottleneck than the bridge capacity itself),
However, the current (2007) discussions about future traffic plans in Auckland, as well as for the
Western Reclamation (an area where a proposed crossing alignment was to be anchored) have put the plans for a second crossing back into public discussion, though most of the plans would still envisage the actual construction to be one or two decades away.
Proposed crossings
Possible alignments
Several solutions have been proposed in the past, including building another bridge alongside the existing one, a tunnel, or combinations of both. Following a detailed scoping study undertaken in 1996, Transit New Zealand identified its preferred options for a new crossing - either a new bridge approximately 500 m west of the bridge connecting to the North-Western Motorway (SH16) via a tunnel underneath Ponsonby and Grey Lynn, or a tunnel slightly to the east of the bridge connecting to the Central Motorway Junction via twin cut-and-cover tunnels under the western CBD / Victoria Park.
In 2006, Transit New Zealand noted that its 10-year plan, at that time being consulted on, would include funding for another study into a second harbour crossing. Some commentators like Brian Rudman have noted that it would make the most sense to keep the new crossing for public transport only, possibly to connect with a rail tunnel to Britomart Transport Centre. This statement was largely supported by North Shore City mayor George Wood, who noted that public transport provision on the new crossing (including the possibility for light rail or heavy rail to connect to Britomart) had been part of North Shore City Council's plans for many years.
A possible tunnel between Mechanics Bay and Northcote was also be considered in the feasibility studies, but was faced increasing criticism from local groups, as well as problems due to the denser residential zones and geographic difficulties faced on such an alignment.
In December 2007, Transit New Zealand noted that the more than 160 options had been narrowed down to only two alignments. The first possible alignment (of approximately 4.5 km length) would be a parallel link several hundred meters directly to the east of the existing bridge (either as a bridge or a tunnel), while the second alignment (of approximately 6.5 km length) would start in the same general environs in North Shore City, but travel diagonally southeastwards to link up with the motorway at Grafton Gully, east of the Auckland CBD. The seond option, due to the need to cross shipping lanes, would need to be a tunnel. It could also possibly be connected to the CBD via a side branch tunnel (for use by public transport only). North Shore City has noted that it would prefer a tunnel option for aesthetic reasons, and to potentially emplace light rail within the tunnel at a future stage.
Replacement bridge
During the public discussions in 2007, an interest group also put forward a proposal to build a new, much larger bridge to the east of the existing structure, and demolish the old Harbour Bridge. They argue that the new bridge, which would be about 50% longer than the existing one, could be constructed to provide for dedicated public transport (including light rail, which is credited with allowing a tripling of the total capacity in people moved over the existing Harbour Bridge), as well as for cyclists and pedestrians. Significantly, they argue that the new bridge would more or less pay for itself, by freeing up new residential land (currently taken up by several km of motorway approaches) in some of the most sought-after Auckland locations like Saint Marys Bay. The proponents claim that the bridge would put more than 35 hectares and open up 3.3 km of shoreline, a prize which would more than make up for the fact that the plans for the Western Reclamation redevelopment would in this case find themselves partly compromised by a major motorway in its area. The new bridge would also be cheaper to operate and wouldn't need emission vents like a tunnel.
The new bridge design, a cantilever spar cable-stayed bridge, was proposed by the Jasmax architectural firm, which note the 'Anzac Centenary Bridge' would be buildable in time for the 100-year memorial of the Gallipoli landings in 1915.
Further Information
Get more info on 'Auckland Harbour Bridge'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://auckland_harbour_bridge.totallyexplained.com">Auckland Harbour Bridge Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
