Whitten Oval Enclosed Facility - Interior View

#3864 Whitten Oval Indoor Training Facility

2024 LSAA Design Awards Entry #3864 Whitten Oval Project

ID NUMBER	3864
ENTRY CATEGORY	3 Large Structures
ENTRANT ROLE	Design / Engineer / Fabrication / Installation
PROJECT NAME:	Whitten Oval Indoor Training Facility
APPLICATION:	Tensile Membrane Roof integrated into a solid-wall building.

PROJECT DESCRIPTION:

Whitten Oval Indoor Training Facility is an example of modern architectural materials incorporated into a high-performance sporting facility. A fully enclosed 50m x 35m building with a tensile membrane roof, rarity in Australia, the facility sets new standards for design innovation and functionality.

The multi-purpose indoor training facility, with its high-translucency PTFE fabric roof allows natural daylight into the indoor field, providing a lighting level much brighter than a traditional building with internal lights.

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The roof is constructed from premium Chukoh Skytop FGT-800 PTFE fabric, a material that offers exceptional strength and durability, and its high translucency enhances the indoor environment.

The Whitten Oval Indoor Training Facility sets a new benchmark in lightweight structural design, showcasing the potential of tensile membrane structures to transform architectural projects with their aesthetic and functional benefits.

PROJECT BRIEF

The Western Bulldogs AFL Football Club is transforming the historic Whitten Oval precinct, introducing a revolutionary 50m x 35m multi-purpose indoor training facility. This facility features a translucent tensile membrane roof, a design choice that is exceptionally rare in Australia, making this project truly distinctive in its ambition and execution.

The architect's vision was to flood the indoor field with natural daylight, ensuring a comfortable training environment year-round while protecting athletes from Melbourne's notoriously unpredictable weather. We collaborated closely with the architect during the initial concept design phase of the tensile membrane roof and subsequently tendered for the Design & Construct (D&C) package.

We proposed using premium PTFE fabric for the roof, selected for its exceptional strength, durability, and suitability for large-scale roofing applications. Our engineering expertise was critical in addressing the loading forces generated by the tensile fabric roof structure, ensuring that the exterior walls maintained their structural integrity under these unique conditions. Additionally, we designed and engineered all secondary steel components and connection details to seamlessly integrate the roof structure with the rest of the building, including a fully bespoke guttering and syphonic drainage system to efficiently manage water dispersal from the tensile membrane roof.

STRUCTURAL SYSTEMS

The final roof design features a rounded rectangular structure supported by eight elegantly curved reclining arches. Valley cables tension the fabric between arch pairs, creating an aesthetically pleasing profile that also provides critical support for the membrane.

The project's wide guttering, essential for effective rainwater runoff, presented a significant challenge. Our scope of work included designing everything from the walls upward, necessitating close collaboration with the head contractor where the guttering intersected with syphonic sumps and downpipes. Each element had to be custom modeled, designed, and fabricated, which led to unforeseen issues during installation. To mitigate such challenges in future projects, we plan to create working prototypes in our warehouse before installation, allowing us to thoroughly test all connections. Fortunately, Melbourne's weather provided ample opportunity for on-site water testing during installation, helping us identify and address any issues promptly.

MATERIALS

For the Whitten Oval Indoor Training Facility Roof project, we proposed Chukoh Skytop FGT-800 PTFE fabric for several key reasons. The higher translucency of PTFE was essential for promoting natural daylight within the indoor facility, creating an environment conducive to training. The large span of the structure necessitated a fabric with high tensile strength to ensure durability and longevity. PTFE fabrics also offer exceptional UV stability, inert properties, and an extremely low surface energy that minimises dirt build-up and extends maintenance intervals. Additionally, PTFE provides the best fire performance characteristics among fabric materials, a critical consideration for safety.

There are almost no examples of fully enclosed buildings with a tensile membrane roof in Australia. While some shopping centres feature tensile membrane skylights and atrium roofs joining separate buildings, the Whitten Oval Indoor Training Facility stands out as a truly unique structure in the Australian landscape.

Building such a distinctive structure required overcoming significant approval hurdles. PTFE and other tensile fabrics are not listed as deemed-to-satisfy roofing materials in the building code, necessitating several design and certification workshops among the architect, builder, and our team to ensure compliance with the National Construction Code (NCC). To address the thermal performance of PTFE, which is relatively low, project consultants conducted thermal modelling of the building. This led to the incorporation of upper-level louvres, providing high levels of ventilation and air movement, a critical aspect of the final building design.

Overcoming these challenges was well worth it. The amount of natural light provided by the 15% translucent roofing material is incredible, offering lighting levels much brighter than a traditional building with internal lights and a more natural quality of light. We hope this unique facility serves as a catalyst for the broader adoption of tensile materials in building roofing, showcasing both their aesthetic and functional benefits.

FABRICATION

The fabrication and construction of the Whitten Oval tensile fabric roof presented several challenges. Due to fabric stock availability and resourcing constraints, we divided the fabrication process between our onsite facility in Australia and our offshore international team. Detailed patterning and fabrication plans, alongside rigorous QA processes, ensured consistency across both teams.

The roof was fabricated in three sections: two panels were produced at our facility in Shanghai, and one at our factory in Brisbane. An exacting and stringent QA system was implemented to mitigate the risks associated with fabricating in two locations. Despite our comprehensive QA process, we discovered an alignment issue with the fabricated rope edges not matching exactly. Fortunately, we were able to rectify the issue locally, avoiding any project delays.

INSTALLATION

The Whitten Oval Indoor Training Facility project provided numerous learning opportunities. We are extremely proud of the design and the finished product, which is truly unique. However, there were several construction aspects we would improve for future projects.

We collaborated with a new Australian steel fabricator recommended by the head contractor. Although we conducted due diligence and factory visits, some aspects of the product did not meet our expectations, causing delays as we rectified these issues. Moving forward, we plan to enhance our monitoring and factory visits to ensure new suppliers meet the stringent requirements for tensile membranes and our quality standards.

The construction phase presented further complexities, with our installation schedule often disrupted by the progress and site clearance of other trades. The height of the structure, with the edge beam starting 13 meters in the air, added significant complexity. On days with little or no wind at ground level, our installers faced different conditions working from an extended EWP. We implemented strict safety measures to ensure the safety of our installation teams, including erecting scaffolding and handrails around the entire gutter installation area.

Despite time pressures exacerbated by Melbourne's unpredictable weather, a series of public holidays in April and May, and union-mandated RDOs, our collaboration with the head contractor remained positive. Ultimately, we are pleased with the project's outcome, particularly the remarkable quality of daylight within the Indoor Training Centre afforded by the unique translucent membrane roof.

The Whitten Oval Indoor Training Facility showcases the innovative application of lightweight tensile membrane roofing being incorporated into a building envelope – with a particular highlight being the remarkable quality of daylight within the Indoor Training Centre afforded by the translucent membrane. This project stands as a testament to the potential of lightweight structures to transform architectural design and functionality.

COSTS

Confidential