Waterview Tunnel construction update

By: Cameron Officer

Waterview Tunnel construction update Waterview Tunnel construction update
Waterview Tunnel construction update Waterview Tunnel construction update
Waterview Tunnel construction update Waterview Tunnel construction update

While work continues underground on the Waterview Connection, a large neatly stacked stockpile of concrete segments is starting to form at the southern end of the project.

While Alice the TBM has been turned around at the Waterview end of the tunnel complex and at the time of writing is back on her way southwards (with a projected break-out at the southern terminus sometime this coming October), all the action moves momentarily to East Tamaki for the Waterview Connection project.

Having produced more than 24,000 concrete segments – each one weighing 10 tonne – to line the motorway tunnels, preparations are now underway to disestablish the Segment Precast Facility at East Tamaki.

When production started in August 2013, the 6000-square-metre, high-tech factory was the most modern pre-cast concrete manufacturing facility in Australasia.

The Precast Sub-Alliance (PSA) established the precast facility to manufacture and deliver the tunnel segments. It operates from 4am to 10pm, five days a week, producing 13.1-metre (int.) diameter rings (each ring has 10 segments, two metres-wide). Forty rings – 400 segments – are produced every week.

The segments have been produced with to-the-millimetre precision, and with the strength and durability to withstand 100 years of demanding use.

Since its establishment around 18 months ago, production staff have so far produced almost 19,500 segments, or about 80 percent of the total required. The final segments will be produced at the end of this month.

"A lot of hard work has gone in through the establishment, pre-production and production phases," says Precast Sub-Alliance (PSA) manager Andy Bould.

Bould says everyone involved in the facility can be proud of what has been achieved.

"This facility was built specifically for Waterview, and investing in the best equipment and having a dedicated workforce is reflected in the standard of segments produced with its high quality finish and consistency."

At neighbouring facilities, the PSA is making 2418 tunnel culvert units, which will be completed in early July, along with 244 Super T beams cast for the Richardson Road Bridge and the Great North Road interchange, which is on track to be completed in January 2016.

Now motorists entering or exiting the motorway at Maioro Street might note hundreds of precast ring segments neatly stacked in the southern construction zone, which stretch all the way to the Southern Approach Trench.

Logistics engineer Devon Bainbridge says that storing 2280 segments on the motorway here (which will eventually make up the final 228 rings in the northbound tunnel) is an efficient and economical solution for the project.

"The production of the segments cannot be halted and there is only so many that they can hold onsite. The motorway expands our storage capacity and ensures uninterrupted production at Tamaki."

A total of 722 deliveries will be required to transport the segments and with as many as 115 delivered a day the motorway extension is already getting a decent workout.

"The segments are transported in sets of three to the site. We have a crawler crane (which is capable of grabbing all three segments in a single lift) sitting on large mats and plywood as to not damage the permanent pavement," says Bainbridge.

The segments will start to be removed during spring.

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