MARGARET COURT ARENA PROJECT:PLEATED ROOF THE CROWNING FEATURE

The Margaret Court Arena project sees the transformation of an existing, under-utilised outdoor tennis court into a year round entertainment venue according to Aurecon Project Director Mark Sheldon. The arena is the final element in the first stage of the $366 million Melbourne Park upgrade.

On completion the 7,500 seat arena will be suitable for tennis, basketball, netball, concert events and will be fully air-conditioned. The crowning feature and most visual component of the venue is a sleek, copper penny coloured roof structure which is acoustically lined, and can be opened or closed in under five minutes.

To produce the “pleated” roof structure, the shape of the major trusses represent a series of interlocking props and ties, and give the appearance that the top chord of the truss has been omitted. The trusses are fabricated from 610mm dia and 508mm dia CHS members, typically ranging in thicknesses from 12.7mm up to 50.1mm.

Utilising the pleated shape of the roof, the operable roof panels consist of a series of folded plates which work as trusses that “lean” on each other, with external members added to accommodate the out-of-balance loads at the perimeter.

Pictured: The major fixed roof truss (below) featuring the “Pleated” top chord, and the Operable Panel leading edge truss during roof construction.

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Photographs shown are representative only of typical applications, current at March 2014.

Collaboration between Aurecon, Lend Lease and GVP Fabricators was the key in developing the erection methodology for the main roof elements. Each step was sequentially planned and agreed, so that pre-cambers and pre-sets for the various elements could be built in, allowing the structure to take its correct geometry after all loads were added.

In a first for Australia, the operable panels are driven by bogies featuring a single rail rack & pinion system for accurate control of the roof positioning. The bogies were supported on 53kg and 86kg rail supplied by OneSteel’s EMRAIL business unit.

Steelwork has been used as the main structural solution for many elements of this difficult project, including a steel framed composite slab for the northern concourse extension, and additional seating tiers built up off the existing concourse (with the addition of steel strengthening beams under the existing slab), and the unique ‘folded plate’ roof.

The concept for Margaret Court Arena by the Joint Venture Architects, NH Architecture + Populous, was that the new building should sit comfortably alongside the existing Rod Laver Arena, which it abuts. It needed to demonstrate that it was a separate building and that it had a more intimate capacity. The desire was to develop a building which sits below the Rod Laver Arena roof and which also has a tennis “high ball” line; a sleek roof profile was required.

The solution was to allow the trailing edge of the roof panels to be supported by the fixed roof via a series of seven mini bogies for each of the two operable panels, which measure approximately 57m x 32m. The concept then allowed a straight-line dimension of only 1.25m between the top of the operable roof panel and the fixed roof. To achieve such a tight dimension, a single downturned major truss across the leading edge of each operable roof panel supported by the drive bogies, which park at the edge of the fixed roof when in the open position, completes the structure. These leading edge trusses span 48.6 metres, are approximately 4.6 metres deep, and are typically fabricated from 406dia x 9.5 CHS members, with a 500WC228 (300PLUS) top chord member. Supporting the leading edge of the fixed roof, which in turn supports the trailing edge of the operable roof panels, are the two interlocking prop/tie trusses which span approximately 65 metres.

Preparatory work commenced on site in March 2012, including extensions to the concourse and back-of-house areas, with major construction works undertaken immediately after the 2013 Australian Open, including the addition of a fixed roof and enclosure wall, prior to “handover” back to the Melbourne and Olympic Parks Trust for the hosting of the 2014 Australian Open.

The fully completed arena will be handed over in November 2014, ready for the 2015 Australian Open.

Above: The photos depict the roof panels pre-assembly jigs designed and assembled by GVP followed by the erection of the individual roof panel safely positioned and fixed on the moving roofs.

Left: Operable Roof Trailing Edge “Mini Bogie”