Taking the traffic out of Taupo
Fulton Hogan adopts a three-zone approach to building a 16 kilometre State Highway 1 bypass of the lakeside holiday resort, which will feature an unusual bridge and flyover. BY GAVIN RILEY
Anyone who has driven through Taupo at the height of summer will have experienced the frustration of having to weave one’s way through the mass of stop-start vehicles and holidaymakers that fills the lakeside resort during the holiday season. It’s not much fun for the town, either.
The problem is age-old. An alternative route for State Highway 1 was first considered nearly half a century ago and an action group was formed as far back as the mid-1980s.
Last November the dream finally began to be realised when a start was made on building the East Taupo Arterial (ETA). This 16 kilometre highway, expected to be completed in March 2011, will run along the eastern outskirts of Taupo from Wairakei in the north to Taupo airport in the south and will include an innovative bridge and flyover.
Fulton Hogan is carrying out the $97.4 million physical-works contract. Just over three-quarters of the project’s overall estimated cost of $110 million is being funded by the New Zealand Transport Agency, with Taupo District Council paying the remainder. Opus is the project consultant.
Fulton Hogan has divided the work into three geographical zones: northern, central and southern (see map).
The company’s project manager, Andrew McRae, says this approach is to make the work more manageable. But there’s another reason. “Each zone has its own challenges, so we’ve built a team in each zone around those challenges. It seems to be working pretty well.”
Northern zone is separated from the rest of the ETA project by the Waikato River and the scope there is heavily weighted towards structures – a bridge over the river and a flyover across the Contact Energy steam field.
Central zone also has structures in the form of two graded separators, plus eight of the project’s nine box culverts and a number of constraints revolving round a Contact Energy steam-field improvement, availability of Department of Conservation land, and the presence nearby of an irrigation farm.
Southern zone is heavily focused on earthworks and drainage and contains the majority of the project’s 34 major culverts, the last two of which are close to completion. The culverts range from single to triple barrel, are up to 2.1 metres in diameter, and are 45 metres to 103 metres long.
The nature of the southern-zone work enabled an early start to be made and, hopefully, will result in an early completion. But a unique challenge is that this zone contains all of the geothermal ground in the project.
McRae says “zoning” is becoming more common on major roading projects, such as the Northern Gateway and SH20 Mt Roskill extension, in order to best manage each section’s discrete challenges and break down the work into bite-sized, manageable chunks.
Earthworks for the ETA began in May and are due to be completed in October – “all part of a strategy to minimise dust and improve the condition of the soil for compaction, because it’s typically pumice and requires a fair bit of moisture to lay, and it’s often dry in summer and difficult to keep the moisture in,” McRae explains.
The earthworks will produce 1.1 million cubic metres of compacted fill, half of which is earmarked for the grade separations at Centennial Drive and Broadlands Road in mid-route (see map). Some 140,000 cubic metres of pumice from two cuts in central zone are being carted in by road for a 500-metre fill embankment between the steam-field flyover and the river bridge, both of which will have steel superstructures.
More than 50 percent of the substructure of the 440-metre flyover is in place. It includes an eight-metre-high abutment and 20 piers up to 20 metres in height. Fabrication of the superstructure steel is underway in Napier and it is hoped the first sections will be on site around October and the structure finished by the middle of next year.
Flying over the steam field
McRae says the flyover has involved an innovative approach. It’s a steel ladder bridge and because of the pumiceous soil there are no piles – the structure sits on shallow concrete pads, sunk two to three metres into ground which has had to be pre-compacted. The specimen design proposed a series of short bridges crossing the plethora of steam pipes which runs through the area. But in the tender design it was decided it would be simpler and more cost-efficient to build a longer structure clear across the field.
“We had to find a way of constructing a 440-metre structure, which is reasonably long. So we’ve opted for the ladder bridge,” McRae says.
Bridging the Waikato
The Waikato River bridge is a network arch structure, a configuration he says is not widely used in New Zealand. At 104 metres it’s longer than a football field and 28 metres farther than the longest span on the Northern Gateway project.
“The whole design and length of the span has been determined by a desire to keep out of the river,” McRae says.
“The specimen design and all of the consenting allowed for some minor intrusion of the piles into the river. We’ve lengthened the span to eliminate that.
“The Waikato is a deep, fast-flowing river, so construction in the river itself was always going to require some fairly substantial reclamation.”
Steel for the bridge’s arch is being fabricated in New Plymouth and it will be launched or erected across the river in three sections using a 400-tonne crane hired from Culham Engineering of Whangarei. The bridge will have two 20-metre-deep, 2.4-metre-diameter piles on each riverbank, specially designed to cope with poor “skin friction” in the pumiceous soil.
Underway at present
Current ETA work includes building a roundabout at the intersection of State Highways 1 and 5 at Wairakei and reconstruction of 800 metres of State Highway 1 to the immediate north.
Creation of a temporary road split began last month to enable the roundabout to be constructed offline from traffic. The 800 metres of road reconstruction, which will involve cuts up to nearly two metres deep, is designed to improve approach grades to the roundabout and drivers’ sight-line. It is anticipated that all this work will be finished by Christmas – in time for the busy holiday season.
Ramps for the grade separated intersections with Centennial Drive and Broadlands Road are being constructed as part of the earthworks programme. The bridges for the intersections are tied to the bridges programme and should be completed by Christmas. The intersection pavements will be finished by next February-March to facilitate access for the construction of the balance of the 150,000-square-metre pavements programme, due to start in October and continue for the duration of the project.
Permeating Fulton Hogan’s expected two and half years’ work on the ETA is the adoption of a “zero harm” policy for its workforce, which will grow from 110 in late winter to 180. The company is striving to prevent even the most minor accident through a system which includes inductions, safety-education programmes, and holding daily on-site and weekly meetings. The result: not one lost-time injury to date.
“Everybody’s trying to improve safety,” McRae says. “Zero harm all starts with a state of mind, where we all believe from workers through to management that every job can and will be done safely and without causing injury. Once we start believing that, we’re able to deliver on it.
“So often you’re challenged by people’s paradigms that injuries will happen in the construction industry. We’ve got to get away from that, where we accept that it’s OK. Zero harm is saying, well, it’s not OK, it’s simply not good enough.
“The number of zero-harm days in itself, and the way they’re reported and communicated, reinforces to the teams that work can be completed without injury. We have to positively reinforce that so we can do it for a long period of time, end on end.”
McRae says safety has to be incorporated into planning and managing work, as opposed to “this is how we’re going to build it, now let’s have a think about safety”.
He adds that after 12 months on site with no lost-time injury, Fulton Hogan is now focusing on first-aid incidents, the nicks and scratches, and asking what occurred, how did it occur, and how can it be prevented?
“Our belief is we’ll win.”
Fulton Hogan is employing a number of key subcontractors on the ETA. They include: Hick Bros Civil Construction, earthworks; Seay Earthmovers, clearing and enabling works, and aggregate supply; E&J Contractors, drainage; Tenix Robt Stone, steel work for the Waikato River bridge; Eastbridge, steel work for the steam-field flyover; J Swap Contractors, pumice cartage by road from central to northern zone, and M4 basecourse supply; Hynds Pipe Systems, pipe supply; Stahlton Engineered Concrete, precast for bridge decks and box culverts; Allied Concrete, readymixed concrete; and Steel & Tube, all steel components.
The presence in that list of two Taupo companies (Seay and E&J) and others with Taupo branches reflects how Fulton Hogan’s increased construction presence in the area is benefiting the local economy. For the ETA contract the company has supplemented its 30-strong Taupo branch with a separate project office that has 30-40 management staff alone.
Company employees have integrated into the community, shop locally, enjoy local hospitality, rent or own homes, have joined local clubs and participate in local events. For instance, Taupo, this year’s New Zealand “top town” winner, recently held a “top team” competition. Fulton Hogan entered an ETA line-up – and won.
Taupo mayor Rick Cooper has said that in the current recession it is exciting to see a major infrastructure project such as the East Taupo Arterial in its physical-construction phase. He has described the steam field flyover as “quite an engineering feat – just one of many we will see with the development of this significant project”.
Fulton Hogan shares his enthusiasm. “As a project team we’re not only focusing on producing an excellent result by constructing a top quality highway, we’re also determined to achieve the highest level of safety, environmental and community outcomes,” says Andrew McRae.
Contractor Vol.33 No.8 September 2009
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