Taking shape - new bridge over Waikato River
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New bridge over Waikato River takes shape
Since reporting in the August 2021 Contractor on the preliminary and early stages of construction of this new bridge, significant progress has been made on the actual bridge structure and approach roads. Richard Silcock reports.
?The Peacocke Road Bridge is part of a near $400 million urban expansion project for the new housing development at Peacocke on the southern fringes of Hamilton City.
The $40 million four-lane bridge which spans the Waikato River was designed by BBO (Bloxam Burnett & Olliver) , Burnett and Oliver (BBO) and is being constructed by HEB Construction .
It comprises three spans; a 70-metre northern section, a 50-metre central section and a 60-metre southern section. It is 180 metres long, 26.2 metres wide and extends well beyond the river banks on both sides. In addition to the four traffic lanes the bridge will also have two dedicated bus lanes.
The bridge stands 30 metres above the level of the river (at normal flow) and is supported by concrete abutments at each end and a single concrete pier supporting a steel lattice frame structure on the southern bank of the river.
The whole project is being funded by the Hamilton City Council with significant input from the Government’s Housing Infrastructure Fund and NZTA.
HEB’s project manager for the bridge construction, Iain Fletcher, who took over from Shane Wilton some 18 months ago, says the initial piling work carried out by sub-contractor, March Construction Ltd was completed in late August 2021 and comprised 40, 1.2 metre in diameter bored piles filled with reinforced concrete.
“The piles are on average 40 metres deep on the north side of the river and 35 metres on the south side,” says Iain.
“This phase of the project was pretty straight forward however we did strike an earth tension crack on the steep northern bank which required the installation of 640 soil nails and geonett matting to provide stability.”
Perhaps the most significant standout feature of the bridge is the Corten weathered steel lattice support structure which sits on the concrete pier on the southern bank. This elongated V-shaped box-like structure beneath the bridge is 31.6 metres long, 21.1 metres wide and 3.2 metres deep and is constructed of four, two metres by 800mm steel girders welded together and weigh in excess of 500 tonnes.
This structure was fabricated and installed by sub-contractor Culham Engineering Company Ltd and was completed at the end of last year over a three week period having been craned into position using a 600 tonne crawler crane operated by Smith Crane & Construction Ltd who, together with HEB Construction subsequently won an award at last year’s Crane Association of New Zealand Inc. Conference for the intricate and complex lift.
“The combination of the huge load, complex lift sequences, the unique lattice structure, the constrained site and difficult mid-air manoeuvring made this pretty interesting,” says Iain.
“Since installing the lattice structure we have placed all of the 36, 45-60 tonne steel beams for the bridge superstructure and these have been bolted together and the deck plates and structural steel reinforcing for the concrete deck has been completed.
“The beams were craned into position from both sides of the river, necessitating moving the cranes from one side to the other and entailed a complete derigging and disassembly before being trucked by heavy haulage units to the other side and reassembled. ?
“The concrete deck for the bridge was poured in late February and took three days to complete over a continuous pouring cycle.
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“The deck paving will be asphalt SMA40 specification and this will be provided by Fulton Hogan utilising asphalt from their nearby plant in Hamilton.”
The bridge has a two percent (3.6 metre) slope from the northern side to the southern side due to the topography of the land on either side of the river.
Apart from the work restrictions imposed by the Covid lockdowns and the extended lock down in Auckland, which impacted on receiving some materials, Iain says it has been a pretty clear run, although a rise in the river level last winter curtailed some operations for a short period.
“We had constructed foundation platforms of aggregate retained by sheet piles for the cranes to operate from and these were 1.5 metres above the average river level, however the river rose above the platforms necessitating a shutdown of crane operations for a short period.
“This, along with some extremely wet weather over last winter has been a bit of a challenge and slowed construction down for a period, as did the Covid lockdowns, but we are back on track and only running a few weeks behind the original completion date which we should be able to claw back.
“We did lose a few people who were travelling from Auckland for a period due to the lock-down border, however since the removal of the Governments ‘traffic light’ system and controls we are experiencing far more absenteeism due to them getting Covid. ?
?“Excluding our sub-contractors we currently have 130 people working on the project, of which 25 are involved in the actual bridge construction.”
In addition to the main bridge, a combined 71 metre-long curved pedestrian/cycleway bridge is being constructed approximately 70 metres to the north (city side) and extends in in arc diagonally across the road approach to the Peacocke Bridge.
This bridge connects the Wairere Drive ring-road with Hamilton Gardens Park and was constructed in five steel sections which were fabricated off-site by PFS Engineering with the sections craned into position over a period of three days.?A visual feature of this bridge, are the two poles (taurapa’s), one at each end which represent the stern of a waka canoe. ?
Schick Civil Construction has carried out the main earthworks for the project, SW Civil and Waipa Civil Ltd are providing the water and storm water utilities and Fulton Hogan will carry out the road paving work.
The overall project is the city’s largest most recent investment in urban expansion and will include, in addition to the Peacocke Bridge and pedestrian/cycleway bridge, a 20,000 people housing development, the construction of new streets, the upgrading and widening of others, a new roundabout, drainage and other utilities, the planting of over 135,000 trees and shrubs and some 15 hectares of gully restoration and wetland areas.
The council’s director for strategic infrastructure, Andrew Parsons says the new Peacocke Bridge not only provides a new transport connection for the expanding southern suburbs, but also carries a number of essential utility services such as water and wastewater pipes, power and broadband/internet cables.
The Peacocke Road Bridge is expected to be completed by late July this year and be open to traffic by September. The pedestrian/cycleway bridge is expected to open next month (April).
Nelson Tasman Regional Franchisee
1 年And the superstructure was fabricated and installed by Eastbridge.