Colorsteel® Bounce® Specified For Cambridge’S Avantidrome

Ten years ago white roofs were hailed as the built environment’s simple answer to global warming. White bounces a large percentage of the sun’s rays away from the roofs of houses and commercial buildings, keeping them cooler in summer and therefore using less energy to maintain a comfortable temperature inside.
Because white reflects both light and heat, surface temperatures build up more slowly and to a significantly lower level. This helps minimise heat transference into the building which means less need for air conditioning to maintain a comfortable temperature, and as a handy side effect the reduced stress on the coating extends its life.

Further challenges remained, however, and many companies including New Zealand Steel and BlueScope Australia continued research on the concept. Now, for the first time in this country COLORSTEEL® Bounce® roofing has been used in a major build.
 
The Avantidrome just north of Cambridge in the Waikato was officially opened by HRH’s Prince William and Princess Catherine in April 2014. This Class One velodrome was a coup for the Waipa district, where high performance rowers are already centred south of Cambridge at Lake Karapiro. Every effort was made to ensure local designers and contractors were used, and New Zealand  Steel was delighted when their new COLORSTEEL® Bounce® roofing was specified.
“COLORSTEEL® Bounce® is a solar-reflecting steel roofing  similar to COLORBOND® Coolmax from BlueScope Australia, and their research was used as a basis for our product,” explains Kirsten Magnusson, Building & Construction Category Manager for New Zealand Steel. “It acts like an extra layer of insulation.”

Its unique paint primer and top coat system is a bright white colour that delivers a 77 percent optimised solar reflectance – 10 percent higher than any other products in New Zealand Steel’s range.  It’s able to do this using specially shaped molecules in the coating that deliver improved reflectance and solar absorption – which can mean lower air conditioning capital costs and significant energy savings for the client going forward.

Lee Roofing of Hamilton was contracted to install COLORSTEEL® Bounce® on the Avantidrome roof. Director Robbie Lee worked on site for the duration of the project, with his two crews.

The major challenge for Steel and Tube was both manufacture and transport to site of the 27 metre long sheets required for the main roof, each weighing nearly 100kg. The sheets required five installers to place them, said Robbie Lee.
The Avantidrome is a tilt support structure where structural steel supports the concrete panels. Outside walls are concrete block with a glass curtain wall featured on the administration block.

The structural design provided “enormous” challenges - the velodrome arena alone is 120 metres long by 77 metres wide, with no internal supporting columns. Instead, a series of ten degree-angled perimeter frames support six-metre high, curved steel space frames, all suspended 20 metres above the track.

This design allows for clear views everywhere in the main arena, but also means the main structure has to be supported from the exterior circumference with no internal supporting columns. The toroid roof shape curves in all four directions, so design parameters were extremely tight to ensure watertightness and architects, engineers and contractors all worked closely together to ensure optimal results.

Bill Muirson, Contracts Manager of Jensen Steel Fabricators who made the steel roof frame, explained that every truss was different. “There was a three degree change for each truss in order to achieve the necessary width and bi-directional curves. The roof alone has a bigger area than Waikato Stadium’s playing surface,” he said.

The skirt roof has a 5 degree pitch and itself took two weeks to lay, said Robbie Lee.  Specially-designed flashings overcame the problem of draping sheets intersecting, and waterfall flashings were installed before the main roof could be erected.

Designers also had to consider the impact of heat generated by high-lumen lighting on the rows of almost-clear fibreglass sheeting installed across the highest points of the roof. This was resolved by using Alsynite’s twin skin technology, in which two separate high-strength fibreglass sheets are laid over each other with a gap between (much like double-glazing on windows) giving condensation the chance to evaporate before building up.

“This was a complex and challenging journey, but we now have a much expanded design and build skill set!” says Dominic Buckell, Director of Chibnall Buckell Marovic Team Architects in Hamilton, who were the project architects.

Nobody in New Zealand had personal experience of constructing a velodrome to a Class One (top international level) standard and there was little help from competitive overseas specialist builders, which meant most solutions were worked out independently.

Client the Home of Cycling Charitable Trust employed three independent structural engineers who met with the construction team and consultants every second week. It was therefore important to be very open at all times said Neville Davy, the Avantidrome Project Manager for Livingstone Building NZ of Te Awamutu who were the lead contractors. The system worked well throughout the build, with more than 30 staff and 80 contractors involved.

Unlike other sports stadia, velodrome tracks are not symmetrical. Each “corner” requires different seating arrangements for the 1,500 spectators, which created unique challenges for the design team who had to take into account sight lines that would allow everyone to see the entire track.

“No two tracks in the world are the same,” explained Dominic Buckell.  “Designs are very specialised as well - there are only two velodrome designers in the world and Ralph Schuermann, who designed the Avantidrome track, is a third-generation velodrome designer and builder.”  Herr Schuermann was also responsible for Invercargill’s velodrome design in 2005, and more recently he designed both the Beijing and Rio de Janeiro Olympic tracks.

The Avantidrome track was designed and pre-assembled in Germany, then shipped over in five-metre sections. Herr Schuermann provided a total of 6,000 co-ordinate points throughout the structure to ensure accurate positioning of the track and seating, 1,500 of which related specifically to the track positioning.

Construction choices have been as environmentally sensitive as possible. The COLORSTEEL® Bounce™ solar-reflective steel roofing will deliver a more stable ambient temperature for minimum air conditioning energy use, provision was made for as much natural light availability as possible, and the 356 high bay lamps provide optimal lighting for minimum cost. These also provide ideal lighting for high definition television coverage.

The $28.5M investment in the Avantidrome complex has clearly been worthwhile, with cyclists at the recent Commonwealth Games in Glasgow earning 15 medals for New Zealand and increased interest in the sport as well as in the Avantidrome displayed ever since.  
“Champions inspire the wider community,” says Geoff Balme, Home of Cycling Charitable Trust’s chief executive. With 80 percent of the track hours in the Avantidrome already logged by community groups not elite athletes, it seems the public agrees. Of course, 15 medals including six gold may have helped too.