Ambition Achieved

Building an extension always presents a few quirky problems to resolve. The challenges grow more interesting when the building site is 10 storeys above street level in the busy business district.

Engineering and management firm Aurecon rose to the challenge to add as many floors of luxury apartments as possible to create Stamford Residences, while minimising the expense of strengthening the existing structure housing the Stamford Plaza hotel.

In the end, Aurecon designed a 10-storey extension comprising 149 apartments, including six penthouses and 10 sub-penthouses. Much of the work for Stamford Residences was done while Stamford Plaza continued to serve hotel guests.

Aurecon needed to produce a light, steel frame extension that wouldn't flex too much in the wind, says Shaun Barrett, executive of Aurecon.

The solution was to hang 350 tonnes of mass dampers at roof level. These are essentially big rectangular concrete pendulums which counteract the sway of the building.

"The pendulums reduce the building's tendency to wobble in the wind," Barrett says.

Wrapping existing concrete columns in carbon fibre provided additional strength for the extension. Barrett compares the new material to wallpaper made of Kevlar, the strong material used in bulletproof vests. The high-tensile carbon-fibre wrap increases the strength of the column, he says.

The connection between the old and new structures required the strength of a foundation for a 10-storey building, Barrett says. Enormous steel plates were used to bolt the steel frame extension to the existing concrete structure.

To boost the strength of the hotel's concrete walls, holes were drilled, some as deep as 12 metres, then filled with reinforcement.

For more information contact Aurecon, Level 4, 139 Carlton Gore Road, Newmarket Auckland, (09) 520 6019. Website: www.aurecongroup.com.

Story by: Trendsideas