Hi-tech in the streets

21:00, Nov 15 2012
polyethylene pipe
UPGRADE: High-density polyethylene pipe is being used to replace concrete stormwater drains between Oxford and Sherratt streets.

Contractors are using hi-tech gear to replace a stormwater drain that runs through Oxford St.

The new high-density polyethylene pipe will replace old concrete pipes that are worn out and in danger of collapsing.

High-density polyethylene, or HDPE, is a polyethylene thermoplastic made from petroleum.

Hadlee and Brunton director David Brunton says the pipe will be buried 5 metres under the road and will stop Sherratt St from flooding during heavy rain.

He says it is one of the largest- diameter pipes installed by horizontal directional drilling in the South Island, and the largest ever installed by that method in South Canterbury.

A Ditchwitch drill was used in the operation, the largest of its type in New Zealand, Mr Brunton said.


The new duct is 700 millimetres in diameter and the 70m pipe will run between Oxford and Sherratt streets.

"It was a very difficult project in terms of getting the line and grade of the pipe correct in very confined spaces," Mr Brunton said.

The pipe was welded at Alpine Energy Stadium, the stadium fence was removed, and the pipe was pulled down in one section through an alleyway at the top of Sherratt St and into position.

Mr Brunton said it took slightly less than an hour to pull the pipe into the ground.

Once completed the new pipe will restore the stormwater capacity under Oxford St. The pipe is expected to last 100 years.

The Timaru Herald