Sustainable Construction: A gem of an example in the Star
(First published 2013)
The strength to weight ratio, the architectural flexibility it allows and the relative ease with which connections are made to existing structures make steel an ideal material for use in vertical extensions and upgrades to multistorey and large entertainment structures.
The Multi-Use Entertainment Facility (MUEF) recently completed at The Star Casino in Sydney both demonstrates and highlights the advantages of steel in vertical extensions. Compared with timber and concrete, steel’s strength can be an order of magnitude superior.
The Star’s new MUEF, framed in steel and covering an area 60 by 40 metres, extends over 16 metres above the existing roof of the main casino building. By utilising steel framing, engineers Taylor Thomson Whitting (TTW) minimised the number of columns and footings which required strengthening. Steel framing provided the architectural flexibility to fit the building envelope, a design based on a multi-facetted gemstone. The structure’s steel composite floors are supported by a series of steel trusses, which are in turn supported by just eight existing columns. The roof is supported by a series of trusses which also provide support for a theatre and conference centre.
Composite floor systems incorporating a relatively thin concrete slab, typically 120mm, and steel beams at approximately three metre centres are typically 20-30% lighter than post-tensioned concrete floors. In the case of the MUEF, the reduced self-weight of the structure and the long term strength gains of concrete in existing columns and footings meant the extent of strengthening structural elements was reduced in quantity and magnitude.
Utilising the strength to weight ratio of steel, and in particular, steel trusses provides long spans and allows column free space; it also reduces the number of existing columns, which require strengthening. For the MUEF this presented a two-fold advantage; reducing the number of columns which require strengthening is generally more economical than reducing the strengthening on a larger number of columns. Secondly, the immediate vicinity around a column requiring strengthening must be untenanted during construction works. The Casino under the MUEF site continued operating during construction, so the financial impact was significantly reduced through limiting the number of columns to be strengthened.
Given the increasing desire of organisations to occupy sustainable buildings, engineers and developers should investigate the opportunities steel framing offers in refurbishing and extending existing buildings.
Organisations prefer to tenant buildings with a modern layout, which meets contemporary functional requirements. Using innovative architectural and engineering design coupled with the use of steel as a sustainable building product assists in the creation of a desirable building for a range of tenants. Tenants, particularly those wishing to promote corporate values of social responsibility prefer to occupy buildings with environmentally sustainable credentials. The MUEF is proof this is achievable, without complete demolition and rebuilding.