Kia ora and welcome to the Winter 2019 update from the Transmission Gully team.
The teams’ Workplace NZ Health and Safety award onsite at the bridge over Cannons Creek.
On Tuesday 28 May, the Transmission Gully Project team's innovative in-crane GPS warning system took out honours for ‘Best use of innovative New Zealand design or technology to eliminate or manage a risk’ at the 2019 New Zealand Workplace Health and Safety awards.
To keep the team safe under high voltage transmission power lines, during construction of the huge pier heads for the bridge over Cannons Creek, the team needed an innovative solution to manage some critical crane lifts and day to day servicing of the piers.
The project’s survey team, and engineers, looked to 3D modelling, and GPS technology for a solution. A much less sophisticated system was already being used onsite on excavators and graders to attain accurate earthworks levels. To fix the complex problem at the bridge over Cannons Creek , the system required a 3D model of the overhead transmission lines and a 3D model of the exact crane setup, to work together simultaneously.
Working with data supplied by Transpower’s engineering team, the project’s survey team created a 3D model to cover all possible locations of the high voltage powerlines under different conditions. For example, wind and temperature – which cause lines to sway and sag, making them a moving target with thousands of possible variations to map. The crane company then provided a 3D model of the crane. This had to include the main boom length, fixed fly jib length and offset angle, back stay ropes and any other elements that could potentially contact the overhead lines.
Once combined, the team could calculate all variables based on the crane’s maximum boom height above the cab (around 70 metres) and the overhead powerline variables. This provided guidance on the best conditions for critical lifts, and to ensure compliance with the required exclusion zone of 10 metres during normal lifts and 6 metres during critical lifts. The separation distances were calculated from the position of the powerline in the most extreme weather conditions, to ensure a safe working distance from the overhead powerlines could be maintained.
The 280 tonne crawler crane, was then equipped with dual mast GPS receivers and the latest Trimble Marine Construction (TMC) software that uses real-time kinematic GPS (RTK) to map the position of the crane’s main boom, fixed jib and main body to within 30mm accuracy.
Onboard, a touch screen shows the operator a 3D view of the crane boom’s proximity to the closest powerline and the closest section of the exclusion zone, ensuring safe operation near the live lines. A two-step alarm system was also installed, to alert the operator to their proximity to the lines. The alarm triggers both visual and audible alerts inside and outside the crane as they aproach the exclusion zone. Trimble Marine Construction confirmed that’s a world first use of this system for this type of lifting application.
Before the critical lifts, the project’s survey team carried out onsite testing to confirm the coordinates displayed by the GPS antenna in the cab of the crane matched the coordinates measured by the surveyor. This confirmation gave the construction team and Transpower confidence that the new system was working and accurate.
Transpower GM Projects, Cobus Nel, said Transpower was proud to have been part of the project that prioritised safety. “We congratulate our colleagues on this prestigious award,” he said. “This is a great example of industry collaboration and clever use of technology to enable CPB HEB Joint Venture’s team to operate safely in a complex and high-risk environment.”
Wellington Gateway Partnership’s CEO, Sergio Mejia, says this is just another example of the project’s commitment to achieving excellence in health and safety in New Zealand.
“CPB HEB JV has navigated their way through a number of design and build challenges thrown at them by the project’s largest structure, and the project team should feel proud of their achievement”, says Sergio.
View looking north over the new northbound bridge over SH1 nearing completion.
The heavily-reinforced concrete columns and bridge girders spanning the Kenepuru-Linden stretch of SH1, are another great technical story of the Transmission Gully motorway.
How to build bridges over State Highway 1 (SH1), Kenepuru Stream and the North Island Main Trunk railway? It’s tricky work that involves some serious planning and innovation by multiple teams and organisations including the likes of KiwRail, NZ Transport Agency and local Councils. One innovative solution involved building a temporary bridge across the Kenepuru Stream to create safe access for workers. This then doubled as a building platform for the central pier of the Kenepuru Link Road bridge being constructed over the stream and railway line.
Replacing the old Collins Avenue overbridge at Linden, which was in fact two bridges side-by-side, required another innovative approach.
Wellington Gateway Partnership’s CEO, Sergio Mejia, says the construction team has had to build the new bridge and demolish the old bridges in stages to keep traffic flowing on SH1. “This process has involved switching traffic and changing the layout of SH1 in this area several times. One of the main challenges for the construction team is working so close to suburban streets and existing traffic. As much as possible, any lane closures happen at night and there is a constant need, for safety reasons, for road users to follow all reduced speed limits and public-access restrictions to the site”, says Sergio.
The Kenepuru Interchange, Transmission Gully motorway northbound bridge over SH1 and Collins Avenue bridges, are all designed to withstand a 1-in-2500-year seismic event. “They shrug off the earthquake by working with it, rather than against it, to sway slightly without endangering traffic.”
The concrete bridge piles, some over 30 metres deep, have air voids between them and their in ground metal casings. This allows for lateral movement to accommodate earthquakes on incredibly strong piles that are socketed into and bearing on bedrock. Distinctive features include “cascading” sleeves with larger diameters at the top than the bottom and bespoke reinforcing designs for each pile to suit specific soils and bedrock depth.
These foundations may be small in comparison to some of the project’s larger structures, but they bring their own set of unique and complex challenges, with innovation at the heart of the build.
Here’s what you can expect to see over the coming months, as the Kenepuru Interchange and Collins Avenue bridges enter their final phases of construction:
Shortly, weather permitting, northbound traffic will be moved onto the stage two section of the new Collins Avenue overbridge. For regularly updated information about traffic impacts on SH1 Linden to Porirua, visit the traffic notices page. For real time traffic updates and information visit NZTAWgtn on Facebook(external link) and Twitter(external link).
On 6 July, we’ll be demolishing the old Collins Avenue northbound bridge, and construction will start on stage three of the new bridge.
Note: Diagrams are not to scale and indicative only.
By the end of July, the final girders for the Kenepuru Link Road bridge over SH1 will be installed, and works will start on constructing the bridge’s deck, ahead of final finishing works.
Works continue for the new Transmission Gully motorway northbound bridge over SH1, with concrete pours for the bridge deck underway. Once complete, the bridge’s side barriers will be installed, and the construction team is set to start driving on the new bridge from the end of July.
We want to thank residents and road users for their continued patience and understanding during construction, and if you have any questions or concerns, please contact us at any time on 0800 84 4636 (0800 TG INFO), or email us at info@tg.co.nz.
View of the bridge over Cannons Creek, which is set to reach the northern abutment at the end of July.
Designing a long, high, curving bridge that is aesthetic yet able to withstand a 1-in-2500-year seismic event, and building it in rugged terrain, requires a special mix of engineering excellence and innovation.
The Transmission Gully project team building the bridge over Cannons Creek, has taken on the challenge, and they’re expertly navigating their way through the build.
Along the way they’ve:
The team’s now defying gravity to construct the bridge and incrementally launch its steel beam sections. These are bolted together behind the southern abutment, slowly launched over the gully, stopping at carefully pre-planned points to connect additional beam sections for launching. The process repeats until the giant structure touches down on the northern side of the gully, passing over the two piers on its way.
Wellington Gateway Partnership’s CEO, Sergio Mejia, says “This is about heavy steelwork, massive bolts, huge temporary works, enormous lifting equipment, precision measurements, strong supporting structures and giant jacks. We’re also working in a sensitive environment, have had to relocate a high-pressure gas line, and are working directly under high voltage power lines. Combine all of these, and you get a sense of how technically challenging the bridge build is, and the innovative design and engineering that comes into play.”
When asked what aspects of the build he’s most proud of, Sergio says hands down it’s the team. “CPB Contractors, HEB Construction and EIC Activities are all part of the project along with our local partners. We have a team of world-class experts on the job – from environmental specialists, designers and engineers, through to our construction crews. Our people are at the heart of innovation. They come up with out of the box, workable solutions, and we’re extremely proud of that.”
Members of the design and construction team, responsible for delivering this iconic structure.
The bridge over Cannons Creek is set to reach the northern abutment – it’s final destination, by the end of July. Following this, the launch nose will be removed and the bridge’s permanent fixings will be installed. By spring, the concrete pours for the bridge deck will be well underway, with the structure set to be complete by early 2020.
Watch a timelapse of the third launch sequence for the bridge over Cannons Creek.
Native specimens onsite at Battle Hill Farm Forest Park, ready for planting.
With just over a million native trees and shrubs left to plant along the 27-kilometre route, the project team is gearing up for another busy winter planting season. With the help of an innovative new planting excavator a whopping 450,000 natives will go in the ground this season.
Wellington Gateway Partnership CEO, Sergio Mejia says that around 534 hectares of land surrounding the new motorway has been fenced and is being planted with around two million native trees and shrubs, including seedlings of long-living tree giants like tōtara, matai and rimu.
“We’re aiming to create one of the most significant lowland bush areas in the Wellington region. Streams along the 27-kilometre route are also being enriched with riparian planting to create better environments for native fish and birds”, says Sergio.
“All seeds have been ‘eco-sourced’ from Wellington, the Kāpiti Coast and the Akatarawa Ranges, as well as from the Transmission Gully motorway route; in other words they’re all local species.”
With many planting areas in ‘hard to reach places’ the team needed to find alternative solutions, to manually hauling hundreds of thousands of plants across hundreds of hectares. Enter Kāpiti Heliworx. Working alongside the project team, choppers are being used to transport between 1,000 and 1,800 natives at a time to their final planting destination. This not only saves the team time, but also helps prevent unnecessary backache and potential damage from carting seedlings overland.
We’re also excited about another piece of kiwi ingenuity being piloted this planting season. The brainchild of the project’s planting contractor Evergreen, a new planting excavator has been developed, to not only ‘dig the hole’, but to fertilize, and then plant selected natives in their correct location. At its top speed, it will see around 2,000 specimens planted in the ground each day.
Check out this cool photo of Evergreen’s new planting excavator being trialed:
With the increased habitat, it’s hoped that iconic songbirds like tui and bellbirds will successfully nest in the new bush and rarer species like native falcon or kārearea will migrate from the Tararua, Rimutaka and Akatarawa Ranges and kākā to and from the likes of Kāpiti Island.
The Landscape Inspection Testing Authority (LITA) has a key role to ensure all native plant species for the project are eco-sourced, and that stringent controls are in place to make sure they thrive – starting from early nursery propagation, through to final planting, and ongoing maintenance once the new motorway is open.
Each eco-sourced native seed is inspected and assigned its own unique barcode, based on where it’s sourced. LITA undertakes regular nursery inspections to check the plant’s progress during its time at the nursery. Once the natives are ready to plant onsite, LITA visits to review and approve the proposed location, and project team’s planting plan. LITA returns once the plants are in the ground, to test the quality of the planting. At the completion of the planting phase, LITA will undertake quarterly inspections, over three years, to ensure the plants continue to thrive.
The Transmission Gully motorway project team partnered with Engineering NZ, and recently took part in the 'Wonder Project rocket challenge'. The challenge runs for six weeks – through May and June, and aims to teach students Newton's laws of motion, spark their creative thinking and inspire them to pursue careers in Science, Technology, Engineering and Mathematics (STEM).
One of the project's Site Engineers, who is a Wonder Project Ambassador, volunteered time each week to support a class of year 7 and 8 students at Pauatahanui School, to design, build and then launch their very own water rockets.
The students also learnt about our Site Engineer's role on the project, and the types of engineering innovation and challenges involved in his job, and how the students could transfer these skills to their own rocket building endeavours.
Two rocket launching kits and parachutes were donated by the Transmission Gully motorway project, along with safety glasses and hi-vis vests, to keep them safe during the launching phase.
Check out the highlights video of the students’ journey over the past six weeks.
At the start of June:
The new motorway route can now be clearly seen winding up the Wainui Saddle from Paekākāriki.
Our winter programme is now well underway across the project and the new motorway is really starting to take shape. Several sections of the alignment are now at pre-pavement level and a massive 76 percent of the project’s structures are complete, with many of the remaining ones set to be finished by the end of winter.
Here’s an update from the team about what’s been happening, and also what’s coming up on the Transmission Gully motorway project.
Paving works are now underway for the Paekākāriki Interchange and where the new motorway will join the Kāpiti expressway, and are set to be complete by the end of winter. Works are also underway to install ITS and lighting, and to complete drainage works. Landscaping is also in full swing. Construction works are also set to get underway over winter for the Mackays Crossing Intersection, located beside the railway line.
View looking south over Paekakariki with paving works underway.
With 85 percent of the earthworks now complete at the Wainui Saddle, the focus during the winter months, weather permitting, will be on bulk earthworks activities to move the remaining earth. Construction works continue on the last of the six batters through this area, along with slope stabilisation, including horizontal drains, rock bolts, pins and shotcrete. By the end of winter, the team will have complete the slope stabilisation down to the final road level, with subgrade construction set to kick off in spring.
View of some impressive bench cuts through the Wainui Saddle.
The team is making great progress at Te Puka Stream, with section six of the permanent stream currently being piped, while the team excavate down to the new stream level. Section seven of the stream has now been diverted and the team are installing erosion and sediment controls. Over the winter months, the team will be focussed on constructing the new stream for sections six and seven of Te Puka Stream, before livening, and building the embankments, and planting natives along the stream’s banks.
For Horokiri Stream, the team is focussed on the Western and upper Eastern Horokiri Stream tributary diversions.
A section of the Horokiri Stream flourishing in its new permanent location.
The team are continuing with final preparation works for pavement through this area, with a focus on finishing the remainder of the bridges, along with undertaking major planting works through the winter months.
A number of natives are set to be planted through the Battle Hill Farm Forest Park area during winter.
The focus of the team through winter will be on finishing works, including paving preparation along the route. Heading south from SH58 through to Cannons Creek, large areas of the new motorway are now at pre-pavement level. Weather dependant, bulk earthworks activities will continue through the winter months. The final concrete pours for the SH58 Interchange bridge deck are now complete, and the team is focussed on completing the lift and placement of the bridge side barriers through winter.
View looking over State Highway 58 Interchange, showing completed bridge deck pours.
With the James Cook Interchange now taking shape, the focus of the team over winter will be to continue with drainage and pavement works. In July, deck pours for the James Cook Interchange bridge are set to get underway.
View looking over the James Cook Interchange, with the Interchange bridge in the top right.
Great progress has been made over summer, with the new link road taking shape. There’s only one large area of fill left to go, before it will connect with the Transmission Gully motorway at the James Cook Interchange by the end of winter.
The team are currently finishing off detailed earthworks, ahead of pre-pavement works starting for the first few sections of the new road. Local road users may notice an increase in heavy vehicles entering and exiting the site at Warspite Avenue during the day. Please take care when travelling through this area, and we thank you for your continued patience during our construction works.
With much of the earthworks complete for the Whitby Link Road, the team are now focussed on their winter programme, which will see the surrounding slopes laden with top soil, and planting of a number of native species. Drainage and channel works will continue, in preparation for the final summer season of works.
The link roads are being constructed by CPB HEB JV under a separate contract for Porirua City Council, and will provide the community with access to the new Transmission Gully motorway once open in 2020.
Visit Porirua City Council’s website (external link)to find out more about the link roads project.
The team recently completed a successful third launch phase for the bridge, with the beams reaching the second pier head over the gully. The final launch phase will see the bridge reach its final destination – the northern abutment, by the end of July. Once complete, the launch nose will be removed, and the bridge’s permanent fixings will be installed by the end of winter. Concrete pouring for the bridge deck will follow in spring, with the structure set to be complete by early 2020.
Construction team at work to attaching the next section of bridge girders ahead of the next launch.
The Transmission Gully motorway project team wishes to sincerely apologise to our neighbours in Tawa, for the noise experienced in the later hours of Friday 14 and Saturday 15 June.
To protect the public from any potential safety risks associated with piling activities in the area, and to work within the safety constraints of the adjacent SH1 traffic, we had to work at night.
We apologise for the disturbance this caused, and wish to let neighbours and road users know, we have now completed these critical works, which will allow for the upcoming traffic switch on SH1 onto the new section of the Collins Avenue overbridge. There are no plans to repeat this particular piling exercise at night again, as this was a unique situation.
Shortly, traffic will be switched over to the new section of the Collins Avenue overbridge on SH1, the team will then prepare to demolish the old northbound Collins Avenue overbridge, which is set to take place on Saturday 6 July. This requires Collins Avenue in Linden to be closed for a 12-hour period. This closure is to ensure the safety of all road users, residents and workers while the old Collins Avenue overbridge is demolished. Note, these works will be weather permitting, and we’ll be in touch with neighbours with more information closer to the day.
Check out the map below for more details on the detour in place for users of Collins Avenue.
Note: Diagrams are not to scale and indicative only.
Please note:The timing of this work is weather dependent, and may change. For regularly updated information about traffic impacts on SH1 Linden to Porirua, visit the traffic notices page. For real time traffic updates and information visit NZTAWgtn on Facebook(external link) and Twitter(external link).
Once complete, the focus for the team during the winter months will shift to construction of the stage three section of the new Collins Avenue overbridge, including excavation and piling works, ahead of construction works starting for the stage three bridge abutments.
For any questions or concerns, contact the Transmission Gully team on 0800 TGINFO (0800 844636) or email info@tg.co.nz
By the end of July, the final span of girders for the Kenepuru Link Road bridge over SH1 will be installed, and works will start to pour the bridge’s deck.
Construction work has started on the Kenepuru Interchange bridge. The Kenepuru Interchange will provide safe access for road users via on and off-ramps to Kenepuru and the new motorway.
Works are now underway to construct the bridge abutments, before girder installation in July, and weather dependent, finishing works are expected to start in late August.
View looking down on works underway for the Kenepuru Link Road bridge spanning SH1.
Works continue for the new Transmission Gully mortorway northbound bridge over SH1 at Linden, with concrete pours for the bridge deck underway. Once complete, the bridge side barriers will be installed, and the construction team is set to start driving on the new bridge from the end of July.
View looking over the northbound Transmission Gully motorway bridge over SH1.
With winter now arrived, our focus from June to September will be on:
The mobile visitor centre is now open onsite at Coastlands, Paraparaumu.
With much of the project happening out of public sight, the mobile visitor centre is a great way for people across the region to learn more about how we’re constructing the new motorway.
Housed in a 20 foot container, the visitor centre includes photos of construction progress, and a series of information panels about the project. The exterior features a specially commissioned mural painted by local Porirua artist Anthony June (Antz).
The visitor centre is located on Rimu Road, behind Pak ’n Save, Coastlands Shopping Centre, until the end of September and is open Monday to Sunday from 10.00am until 4.00pm.
View over works underway at SH58, with Whitby and the Porirua Harbour in the background.
Check out the project’s image gallery to view the latest photos of the motorway from the air and on the ground.
Visit our video library to see animated videos of the Interchanges and innovative construction works for the project.
Don’t forget to tell your friends and family to sign up(external link) to receive the latest project news.
We hope you enjoy reading these updates, and we’d love to hear from you. If you have any questions, comments or story suggestions, you can email them to info@tg.co.nz
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