Lakeside construction challenges tackled

Lakeside construction challenges tackled with skill and technology

Challenges posed in the redevelopment of Queenstown’s iconic and historic Mountaineer building are being met by innovative techniques from Rilean Construction and site engineers.

Rilean Construction, retained by developer Westwood Group Holdings to manage the high profile project, is using specialist skills and equipment to add stability to the foundations and keep ground water in check.

“The machinery we’re using is relatively new to New Zealand and similar to that used widely on projects adjacent to London’s Thames River,” said Gary Dent, Rilean Construction Director.

“Projects close to bodies of water, like this one, need to be carefully managed. The Mountaineer site calls for the most technically advanced drilling machinery available which enables us to install stabilising continuous secant (overlapping) concrete piles, as we simultaneously remove drilled alluvium from the ground.”

The top of the range drilling rig, initially imported from Italy, is one of only three in the country and is used to drill the 10.5 metre deep piles.

“Because The Mountaineer Facade is only 100 or so metres from Lake Wakatipu and is an historic site, we’ve put every safeguard in place to protect it.”

Gary said creating the contiguous secant wall is fundamental to establishing a strong barrier to the ground water during construction. Every second pile is reinforced, and then all piles are structurally tied to the main structure ring beam.

“We first created all the piles around the perimeter of the site which assist in keeping the heritage walls in position, but primarily retain the adjacent footpaths.

“The second stage of the piling (tension piles) are being installed in the centre of the site to give the building stability and prevent it from uplift and movement in the event of any seismic activity.”

Now 12 weeks into the piling programme of the redevelopment, The Mountaineer already has 271 of its 360 concrete piles in place and building work continues behind the 6m tall pictorial Hessian sheeting.

The next phase of construction will involve site ‘dewatering’ later in the month.

One hundred and twenty years of history will be reflected in the restoration of the building façade and the interior rebuild, scheduled for completion by 2009.

The Mountaineer is located on the Corner of Rees, Shotover and Beach Streets in Queenstown.