Highway repairs worth the wait

MORE than $4million worth of repair work on the Gwydir Highway between Grafton and Glen Innes has survived its sternest test even before it has been completed.

The repairs to the highway at the hairpin bend near the top of the Gibraltar Range yesterday bore up under the weight of two huge vehicles carrying two pressure vessels from Sawtell to the Olympic Dam in South Australia.

The first vehicle measures 54 metres in length, is seven metres wide, six metres high and weighs 252 tonnes. The second is 30 metres in length, six metres wide, six metres high and weighs 120 tonnes.

Roads and Maritime Services engineer and project head Brendan Rounds said the 18-month repair project, forced by road slips that occurred in January 2013, had been tweaked to allow the massive vehicles through on time.

Mr Rounds said the road slips had cut the highway at three points and caused major damage at two sites.

The most serious damage occurred on the hairpin bend where the hillside under the highway had collapsed, cutting the road at the bottom of the loop and allowing a torrent of water to scour out the road surface.

Mr Rounds said RMS staff spent almost a year surveying the damage and devising the best solutions to the problem.

"Slip one, at the top of the hairpin, was the most serious," he said.

Mr Rounds said the repair technique required the hillside to be stabilised by driving five rows of 25mm nails 8-9metres into the bedrock, then anchoring them to a reinforced concrete wall.

Mr Rounds said this then had to be strengthened to allow the two vehicles to pass the site safely.

"We looked at what could happen if we increased the size of the nails in the top two rows and figured this would give the repairs the strength they needed," he said.

Mr Rounds said work at the site should be completed by mid-July.

"Normally the RMS allows 18 months for a single major repair job, so getting one as complex as this done in the time we've done it is pretty good," he said.

"We made it our major priority on the North Coast."

THE TRIP

Details of the journey are as follows:

Friday, June 27 at 10pm to Saturday, 28 June at 8am
Depart Sawtell for Mann River at Jackadgery
Move via the Pacific Highway, Solitary Islands Way, and Gwydir Highway

Sunday, June 29, from 7-5pm
Travel to Tenterfield
Move via Gwydir Highway onto the New England Highway

Monday, June 30, 7-5pm
Travel to Moree
Via Bruxner and Newell highways

Tuesday, July 1, 7-5pm
Travel to Walgett
Via Newell, Kamilaroi highways

Wednesday, July 2, 7-5pm
Travel to Cobar
Via Kamilaroi, Mitchell highways, Kidman Way

Thursday, July 3, 7-5pm
Travel to Broken Hill
Via Barrier Highway

Friday, July 4 at 9am
Travel to NSW/SA border
Via Barrier Highway