Kopu Bridge
Encyclopedia
The Kopu Bridge is a single-lane
swing bridge
that spans the Waihou River
, near its emergence into the Firth of Thames
in the Thames-Coromandel District
of New Zealand
's North Island
. The bridge was completed in 1928 and is part of State Highway
25. The swinging span in the middle of the bridge is 43 metres long and with an overall length of 463 metres, the bridge is the longest and oldest single lane bridge within the state highway network.
As the first available crossing of the Waihou River and the main link between the Hauraki Plains
and Coromandel Peninsula
, it sees a lot of traffic, especially during holidays. Due to a gradual increase in the traffic between Auckland
and the Coromandel Peninsula, by the early 1990s the bridge became the most heavily used single lane bridge in the country, with traffic volumes of an average of 9,000 vehicles per day. Traffic flow over the bridge is controlled by traffic lights and the bridge is notorious for queues which form during peak times such as holiday weekends, when three hours delay are common. As of 2010, construction on a replacement bridge is ongoing directly to the south of the old Kopu Bridge.
While rarely used nowadays as boat traffic has declined (especially for shipping use, with the river once navigable all the way up to the town of Paeroa
), the swing span can still open, and provide a 15.3 m wide channel to passing vessels.
The bridge is the only surviving road bridge of the swing span type in the country and the New Zealand Historic Places Trust
lists the bridge as a Category 1 historic place, while it is also on the IPENZ Engineering Heritage Register.
It replaced the barges and ferries which had until then served to cross the Waihou River
, connected Thames to the newly drained dairy farming grounds of the Hauraki Plains, and was reckoned to have made a big difference to the local district, having marked the local shift from river transport to road transport becoming dominant, and to Thames moving from a mining town towards a farming service community. It was also considered a project typical of the time and of New Zealand Prime Minister Gordon Coates
quest to develop the rural economy.
Up to the 1960s, traffic used the passing bays, but after angry confrontations between motorists had become more common, lights were installed. Until that time, the bridge had still sometimes used for herding of livestock, but soon after the signalisation, further increasing traffic queues began causing calls for a replacement bridge. In late 2009, a webcam
was installed to allow online checking of queue lengths during the holiday periods, a feature that in New Zealand had so far been limited to urban areas.
, and that it had failed to pass safety inspections which require the ability to withstand a 2,500 year return period quake. In 2006, Transit New Zealand
announced their intention to build a second bridge slightly upstream of the existing bridge and to route the State Highway over the new bridge. However, the start date was at that time set for no earlier than 2011, which was later brought forward to late 2009 by National as part of an economic stimulus package.
The new bridge will be 587 m long, and have 16 spans, with its foundations being driven 36 m to 50 m deep into the riverbed, due to the soft swampy ground not providing good support otherwise. Much of the ground would also have to be forcibly compacted first. The design incorporates images of waka
and taniwha
, and landscaping using native plants. The replacement was to originally cost $32 million, this later rose to $47–48 million, also including 2.5 km of new approach road as well as a new roundabout near Thames.
The bridge's navigation channel at the central span will be 42.8 m wide and 6.5 m above mean sea level, allowing larger vessels to pass under it, without the need for a swing bridge as for the old structure.
As of February 2010, works on the new bridge were reported as proceeding on schedule for a 2012 completion, and employing around 40 people on site, and another 100 in the wider area, with NZTA making an effort to source much of their material locally. The New Zealand Labour Party
has however criticised this claim, noting that only 3,000 of the 11,000 tonnes of steel to be used are sourced from within New Zealand, despite claims that the country's steel industry was well able to provide the remaining steel in terms of volume and quality.
As of January 2011, 10 of the 15 piles for the new bridge had been sunk. However, the contractor noted that this would not enable an earlier-than-expected completion date - since it would still take more time until the soft soils on the approach roads was sufficiently compacted and stable under a bed of rubble (though 1 m settlement had been reached as of early 2011, 2m will be required). Therefore, the expectation was still for completion in mid 2012.
Due to its historical significance, the existing bridge will be retained and upgraded, possibly to be integrated into a new cycleway along the coast - though the new bridge will also provide access to cyclists and walkers.
Lane
A lane is a part of the roadway within a road marked out for use by a single line of vehicles in such a way as to control and guide drivers for the purpose of reducing traffic conflicts. Most public roads have at least two lanes, one for traffic in each direction, separated by Lane markings...
swing bridge
Swing bridge
A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its centre of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right...
that spans the Waihou River
Waihou River
thumb|The Waihou River near [[Putaruru]]The Waihou River is located in the northern North Island of New Zealand. Its former name, Thames River, was bestowed by Captain James Cook....
, near its emergence into the Firth of Thames
Firth of Thames
The Firth of Thames is a large bay located in the north of the North Island of New Zealand. It is the firth of the rivers Waihou and Piako, the former of which was formerly named the Thames River, and the town of Thames lies on its southeastern coast....
in the Thames-Coromandel District
Thames-Coromandel District
The Thames-Coromandel District Council in the North Island of New Zealand is seated in the town of Thames. It is located in the region around the Firth of Thames and Coromandel Peninsula, to the southeast of Auckland...
of New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
's North Island
North Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
. The bridge was completed in 1928 and is part of State Highway
New Zealand State Highway network
The New Zealand State Highway network is the major national highway network in New Zealand. Just under 100 roads in both the North and South Islands are State Highways...
25. The swinging span in the middle of the bridge is 43 metres long and with an overall length of 463 metres, the bridge is the longest and oldest single lane bridge within the state highway network.
As the first available crossing of the Waihou River and the main link between the Hauraki Plains
Hauraki Plains
The Hauraki Plains are a geographical feature and non-administrative area located in the northern North Island of New Zealand, at the lower end of the Thames Valley...
and Coromandel Peninsula
Coromandel Peninsula
The Coromandel Peninsula lies in the North Island of New Zealand. It is part of the Waikato Region and Thames-Coromandel District and extends 85 kilometres north from the western end of the Bay of Plenty, forming a natural barrier to protect the Hauraki Gulf and the Firth of Thames in the west...
, it sees a lot of traffic, especially during holidays. Due to a gradual increase in the traffic between Auckland
Auckland
The Auckland metropolitan area , in the North Island of New Zealand, is the largest and most populous urban area in the country with residents, percent of the country's population. Auckland also has the largest Polynesian population of any city in the world...
and the Coromandel Peninsula, by the early 1990s the bridge became the most heavily used single lane bridge in the country, with traffic volumes of an average of 9,000 vehicles per day. Traffic flow over the bridge is controlled by traffic lights and the bridge is notorious for queues which form during peak times such as holiday weekends, when three hours delay are common. As of 2010, construction on a replacement bridge is ongoing directly to the south of the old Kopu Bridge.
While rarely used nowadays as boat traffic has declined (especially for shipping use, with the river once navigable all the way up to the town of Paeroa
Paeroa
Paeroa is a small town in New Zealand, in the northern Waikato region of the Thames Valley. Located at the foot of the Coromandel Peninsula, it is close to the junction of the Waihou and Ohinemuri Rivers, 20 kilometres from the coast at the Firth of Thames...
), the swing span can still open, and provide a 15.3 m wide channel to passing vessels.
The bridge is the only surviving road bridge of the swing span type in the country and the New Zealand Historic Places Trust
New Zealand Historic Places Trust
The New Zealand Historic Places Trust is a non-profit trust that advocates for the protection of ancestral sites and heritage buildings in New Zealand...
lists the bridge as a Category 1 historic place, while it is also on the IPENZ Engineering Heritage Register.
History
The original bridge was built in 1928, under the lead of the Main Highways Board after negotiations over its construction started in 1911, and planning begun in 1922. It was one of the largest such works of its time, with 23 spans and advanced deep piling for the soft ground of the river bed.It replaced the barges and ferries which had until then served to cross the Waihou River
Waihou River
thumb|The Waihou River near [[Putaruru]]The Waihou River is located in the northern North Island of New Zealand. Its former name, Thames River, was bestowed by Captain James Cook....
, connected Thames to the newly drained dairy farming grounds of the Hauraki Plains, and was reckoned to have made a big difference to the local district, having marked the local shift from river transport to road transport becoming dominant, and to Thames moving from a mining town towards a farming service community. It was also considered a project typical of the time and of New Zealand Prime Minister Gordon Coates
Gordon Coates
Joseph Gordon Coates, MC and bar served as the 21st Prime Minister of New Zealand from 1925 to 1928.- Early life :Born on the Hukatere Peninsula in Kaipara Harbour where his family ran a farm, Coates took on significant responsibility at a relatively early age because his father suffered from...
quest to develop the rural economy.
Up to the 1960s, traffic used the passing bays, but after angry confrontations between motorists had become more common, lights were installed. Until that time, the bridge had still sometimes used for herding of livestock, but soon after the signalisation, further increasing traffic queues began causing calls for a replacement bridge. In late 2009, a webcam
Webcam
A webcam is a video camera that feeds its images in real time to a computer or computer network, often via USB, ethernet, or Wi-Fi.Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a video camera...
was installed to allow online checking of queue lengths during the holiday periods, a feature that in New Zealand had so far been limited to urban areas.
Replacement
In addition to the constrained traffic over the bridge (with flows projected to increase by 2% per year over the next 15 years), investigations in 2001 had also found that the bridge was likely to be severely damaged or might even collapse in an earthquake stronger than that of a 300-500 year return periodReturn period
A return period also known as a recurrence interval is an estimate of the interval of time between events like an earthquake, flood or river discharge flow of a certain intensity or size. It is a statistical measurement denoting the average recurrence interval over an extended period of time, and...
, and that it had failed to pass safety inspections which require the ability to withstand a 2,500 year return period quake. In 2006, Transit New Zealand
Transit New Zealand
Transit New Zealand was, from 1989 to 2008, the New Zealand Crown entity responsible for operating and planning the New Zealand State Highway network...
announced their intention to build a second bridge slightly upstream of the existing bridge and to route the State Highway over the new bridge. However, the start date was at that time set for no earlier than 2011, which was later brought forward to late 2009 by National as part of an economic stimulus package.
The new bridge will be 587 m long, and have 16 spans, with its foundations being driven 36 m to 50 m deep into the riverbed, due to the soft swampy ground not providing good support otherwise. Much of the ground would also have to be forcibly compacted first. The design incorporates images of waka
Waka (canoe)
Waka are Māori watercraft, usually canoes ranging in size from small, unornamented canoes used for fishing and river travel, to large decorated war canoes up to long...
and taniwha
Taniwha
In Māori mythology, taniwha are beings that live in deep pools in rivers, dark caves, or in the sea, especially in places with dangerous currents or deceptive breakers...
, and landscaping using native plants. The replacement was to originally cost $32 million, this later rose to $47–48 million, also including 2.5 km of new approach road as well as a new roundabout near Thames.
The bridge's navigation channel at the central span will be 42.8 m wide and 6.5 m above mean sea level, allowing larger vessels to pass under it, without the need for a swing bridge as for the old structure.
As of February 2010, works on the new bridge were reported as proceeding on schedule for a 2012 completion, and employing around 40 people on site, and another 100 in the wider area, with NZTA making an effort to source much of their material locally. The New Zealand Labour Party
New Zealand Labour Party
The New Zealand Labour Party is a New Zealand political party. It describes itself as centre-left and socially progressive and has been one of the two primary parties of New Zealand politics since 1935....
has however criticised this claim, noting that only 3,000 of the 11,000 tonnes of steel to be used are sourced from within New Zealand, despite claims that the country's steel industry was well able to provide the remaining steel in terms of volume and quality.
As of January 2011, 10 of the 15 piles for the new bridge had been sunk. However, the contractor noted that this would not enable an earlier-than-expected completion date - since it would still take more time until the soft soils on the approach roads was sufficiently compacted and stable under a bed of rubble (though 1 m settlement had been reached as of early 2011, 2m will be required). Therefore, the expectation was still for completion in mid 2012.
Due to its historical significance, the existing bridge will be retained and upgraded, possibly to be integrated into a new cycleway along the coast - though the new bridge will also provide access to cyclists and walkers.
External links
- SH25 Kopu Bridge (NZTANew Zealand Transport AgencyThe New Zealand Transport Agency is a New Zealand Crown entity tasked with promoting safe and functional transport by land, including the responsibility for driver and vehicle licensing and investigating rail accidents. It was created on 1 August 2008 by the Land Transport Management Amendment...
project website)