Raising the bar SKM engineered stadium roof

It seemed like an impossible brief a stadium with a permanently closed roof and natural turf. So it was not surprising that the company contracted to provide structural engineering services for both the roof and supporting stand structures for the Forsyth Barr Stadium in Dunedin needed a solution with a high degree of innovation.

Project manager Trevor Robertson of Sinclair Knight Merz (SKM) says that to assure good turf health, the design needed to maximise the sun's penetration and allow good cross-flow ventilation to promote strong root growth.

"The developed solution was for a relatively low transparent roof spanning the full area of the playing field and angled for beneficial transmission of sunlight to turf level," Robertson says. "This was a world first, and consequently there were many challenges for the designers."

Robertson says to design such a massive and complex roof spanning two independent building structures in a seismically active country and an area subject to snow and temperature extremes, required careful consideration of complex load cases and structural responses. Some novel approaches to seismic energy dissipation were incorporated to help keep the roof structure as slender as possible, to minimise shadowing.

Three separate and specific types of energy dissipaters appear in addition to the conventional eccentrically braced frames. There are steel tapered plate dissipaters between the roof and South Stand; novel tension/compression yielding struts within the North Stand concentric bracing; and tension/compression yielding steel bars at the base of the South Stand rakers. Wind tunnel testing helped to improve design efficiency and reliability.

To contact Sinclair Knight Merz, phone +64 9 928 5500, fax +64 9 928 5501. Email: trobertson@globalskm.com. Website: www.globalskm.com.

Story by: Trendsideas