Gunyama Park Aquatic and Recreation Centre

Entrant: 
Jan Jober-Studnicka - Kirk Roberts Consulting

Category: 
10. Innovation timber engineering award

Photographed by: 
Childs play area - Peter Bennetts / Empty pool completed and exterior - Rodrigo Vargas / Onsite - engineer

Engineering the longest free-spanning mass timber beams in Australasia.

The Gunyama Park Aquatic and Recreation Centre is the largest pool complex built in Sydney since the 2000 Olympic games, and features ‘Kiwi’ structural engineering ingenuity in the form of the longest free-spanning mass timber beams in Australasia.

Kirk Roberts Consulting structural engineers were engaged to provide innovative solutions in order to achieve the desired industrial-scale trellis look for the roof component of the project. Referencing the area's industrial history, ten timber roof rafters manufactured out of New Zealand radiata pine are spaced 4.8 meters apart. This creates a 52m by 36m column-free space below. In order to maximise light transmission through the roof, no secondary members between roof beams were proposed. The design needed to ensure the stability of the beams to accommodate not only gravity and wind load, but also high tensile lateral loads induced by the ETFE cushions.

Each roof rafter consists of a pair of glue-laminated beams jointed by a continuous Cross Laminated Timber (CLT) panel as a top flange, to form a composite section. This increased the strength and stiffness of the beams and helped to control rafter depth. Each glulam beam was assembled from three 12m long segments with hidden mechanical connections, concealing any visual joints in the glulam. The spliced connections allowed the beams to be transported from New Zealand to Sydney, assembled on-site and lifted into place as one 36-metre-long composite piece, reducing construction risks. The joint connection design at the splice also sped up the beams' onsite installation for the contractors. Our innovation in this design meant that steel components were hidden within the wooden beams, providing the required stability and meeting the architectural vision, while also protecting the steel elements within the beam from the corrosive indoor pool environment.

The beams were a crucial primary design element, with the look of an industrial-scale trellis linking to the area’s industrial history. This design maximised the use of natural sunlight while also supporting the structural form of the aquatic centre. The timber beams provide an aesthetically designed roof that allows high natural light transmission and manages heat transfer but does not degrade under the pool’s aggressive environmental conditions, achieving form and function in a creative way.

When comparing timber to other materials often used in indoor swimming pool environments such as steel, timber has natural durability and is corrosion resistant, resulting in reduced long-term maintenance.

This project is clearly very unique. Featuring the longest free-spanning timber beams in Australasia, Gunyama is the only aquatic centre development of its size and scale within Sydney since the 2000 Olympics. The highly complex engineered steel splices every 12m, are completely hidden and protected from the chemical environment creating both a seamless look and practical solution. Our innovative engineers found a creative way to utilise timber to fulfil not only arc