Melview Developments has embarked on the most ambitious hotel and residential construction ever undertaken in the South Island. There are no fewer than 13 buildings to be constructed on Kawarau Falls Station site near Queenstown. Five different architectural firms were commissioned to design the buildings concurrently, sharing a palette of materials but given individual briefs. The result is a cohesive yet diverse stable of structures.

Clark Brown Architects was assigned a site at Kingston West for what will be branded as a Quadrant Hotel. Architect Natalie Snowden says: “The design accepted by the client was for a building seven storeys high, with two levels of basement parking and 98 rooms. The steep, north-facing sloping site is ideally orientated for optimal sun and natural light, as well as magnificent views of Lake Wakatipu, the Remarkables and Coronet Peak. The reception, bar, café and retail units are at levels three and four, with conference facilities, a commercial kitchen and plant rooms all tucked into the south side of the building below ground level. Offices for the staff and hotel management are on level four, which opens to a large courtyard at the east end of the building. This provides natural light to adjacent internal spaces and is bounded by a system of two-storey steel trusses. These reduce the requirement for columns in the car park, freeing up circulation and also providing architectural interest.”

Design engineer Jeff Clendon of Holmes Consulting Group says that because the structure follows the height restriction plane, the building is partially cut into the ground and has different heights along its length. “The roofs and floor diaphragms span horizontally to distribute earthquake loads to a mixed system of concrete shear walls acting in the transverse, north-south direction, with moment-resisting steel frames acting in the longitudinal, east-west direction. The moment-resisting steel frames extend down the length of the building on the north and south facades, and essentially run from roof level down to level three, which is the lowest “ground” level. The level three diaphragm is connected to the surrounding ground by a series of rock anchors. Below this level, longitudinal basement walls distribute residual earthquake loads to the ground.

“With floor-to-floor heights being at a minimum, steel beam depths were critical; both the composite and non-composite beam design required non-standard solutions in critical areas to maintain head heights. A number of beams required haunches and steel plating to satisfy the design constraints. The roof is typically of lightweight construction, consisting of low-pitched membrane or iron roofing on timber packing over steel purlins and regular steel rafters, with posts to the concrete floors below.”

At the time of tendering the sub-contractors, the labour market was very tight in Queenstown, making pre-assembly of the bathrooms an attractive option. The high quality factory-produced modules were delivered to site wrapped in plastic. Because each bathroom had to be installed before the floor above could be constructed, they appeared in the programme earlier than they would have done if built on site. The bathrooms were plumbed and wired into the main services as they were installed. This went smoothly because the steel beam penetrations for the pipes had been identified and designed in advance. The structural steel was fabricated offsite by C.J. Saunders Ltd. “Knowing what penetrations and haunching were required,” says Cliff Saunders, “meant that our steel pricing could also be accurate. The bathrooms were designed to sit on Parallel Flange Channels, and the pre-cast concrete floors of the bathrooms became part of the finished structural floor slab.”

SCNZ: “What was your biggest challenge in this project?”

Cliff Saunders: “The site resembles a quarry, with no setting down room. This meant we were in deliver-and-erect mode, craning the steelwork straight off the truck and bolting it into position immediately. We even did this with the three trusses, the two biggest of which were 18m long and 6.5m deep. We transported all three as one load, weighing a total of 15 tonnes, from Dunedin to site and got them up the same day. As the project advanced, each finished floor area became our setting down space for the next stage of steel.”

The building provides vehicle and pedestrian access to the adjacent Lakeside West and Lakeside Central West buildings via underground tunnels. The Quadrant Hotel is destined to be a designer 4 star hotel and construction is scheduled for completion by November 2009.