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The steel truss, which gives the TelstraClear Pacific Events Centre its distinctive appearance, was the result of a complex process of structural engineering.

Months of preparation included fabrication of steel at sub-contractor Grayson Engineering's workshop, as well the on-site assembly of the separate pieces.

Initially, Grayson Engineering's drawing office produced fabrication drawings of the structure using a customised steel detailing computer program, says commercial manager Colin Berger.

"Because of this project's complex geometry the detailing program was invaluable," he says. "These drawings provided the templates for a custom-made pipe-profiling machine, which allowed all the pipe ends to be accurately profiled to the correct shape. Lasers were then used to fabricate the nodes from determined setup points."

Although the geometry was challenging, all components fitted perfectly, even at the eight intersecting pipe sections of the busiest node, he says.

To maintain high levels of accuracy, as much steel as possible was fabricated off-site in a controlled workshop environment, says Berger.

The truss was fabricated into modules that were then transported in eight pieces to the site. The loads were transported at night, with the largest being 13m wide and 12m high. Once onsite it took three months for the truss to be assembled.

For safety reasons, and to speed up the project, the truss was assembled in a positionadjacent to the main structure. By not erecting the truss over the heads of other contractors delays were prevented.

Once ready, three cranes lifted the truss into place. A 200-tonne American crawler crane supported one end, while two hydraulic cranes supported the other end of the truss. This is thought to be New Zealand's biggest single span lift.

For more information, contact Grayson Engineering, phone (09) 262 3097. Website: www.grayson-engineering.co.nz. Email: colin-berger@grayson-engineering.co.nz.

Story by: Trendsideas