It's going so well

Dated: October 2012 Display all Projects
Principal: New Zealand Transport Agency (NZTA)
Customer: Well-Connected Alliance
Location: Hendon Ave sewer diversion
Product: Double Slide Rail Shoring System
Concept only

After years of planning and proposed configurations, the New Zealand Transport Agency (NZTA) has begun construction on its largest, most challenging and expensive project to date – the Waterview Connection project.  The tunnel, motorway and interchange contract was awarded to the ‘Well-Connected Alliance’ back in August 2011. With this massive project just getting underway Trench Shoring New Zealand has been called upon to supply shoring equipment for the Hendon Ave sewer diversion, one of the first stages to the project, with the aim of ensuring that the number one priority on the project objectives list – to be injury free – is met.

“This is a very large project and we are very glad to be involved in the early stages with the supply of our shoring systems,” says Frank Swanberg, General Manager for Trench Shoring New Zealand Ltd (TSNZ).

Project objectives:

  • Injury free
  • Fully integrated, efficient, safe link
  • Balance social, environmental and economic
  • Best use of money
  • Highly collaborative relationships
  • Exceptional people development

“We have 10 Double Slide Rail modules on site allowing staff from the Well-Connected Alliance to have 44m of shored trench to work in,” said Laurie Pearce, Sales Engineer for TSNZ.

Working in trenches of 5.5 to 6m means the use of shoring systems is essential. Kevin Connolly, Drainage Supervisor for the Alliance, explains, “the redirected sewer is going through about 150m of an old landfill so the ground is very unstable. We have used TSNZ’s systems on various projects, they are a must to ensure everyone is always kept safe.”

With this thinking Kevin has developed further safety measures to ensure his team can enter and exit the deep trenches safely. “Kevin and the team have devised an inertia reel system, whereby his guys are on a harness and line as they enter and exit the trench to help prevent falls from the ladder access. He is also currently working on a lifting device, again to aid his team,” adds Laurie.

The eventual load from the new highway above has meant the new sewer line is being encased in concrete. “We are using a polystyrene panel, as we pour the concrete, to prevent the shoring system from being concreted in,” adds Kevin. “Everything is going well. It’s a fantastic system, in fact we had planned to use the shoring systems through the difficult soil conditions but it looks like we may keep using it for about half of the distance as it’s just going so well.”

With five years of work ahead for the Alliance, relief is felt by all involved as the biggest project in the country gets into first gear. 

The Well-Connected Consortium comprises of: 
NZ Transport Agency, Fletcher Construction, McConnell Dowell Constructors, Obayashi Corporation, Parsons Brinkerhoff Zealand, Beca Infrastructure and Tonkin & Taylor.

Quick facts:
Project objective: Complete Western Ring Route
Project duration: 66 months
Length: 4.8km of 6-lane motorway
Tunnel length: 2.5km
Tunnel diameter: 14m (twin tunnels)
Maximum depth: 45m Tunnelling method: Earth Pressure Balance Machine Project cost: NZ$1.4B

Follow Us on Facebook


  • New "Multibox" is available now

    TSNZ launches a new slide rail manhole box variant. Available in NZ now, the new Multibox...


  • Did you know that there are regulations that apply to excavations over 1.5m deep
    Are you at risk of breaching them?

    We can help!