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TERMITE PROOF STEEL FRAME FOR OUTBACK COMMUNITY FACILITIES

Steel framing is playing a major role in providing the necessary infrastructure for aboriginal communities in remote parts of Australia. The latest example is the Well -being Centre and two houses for staff constructed at Aurukun in Northern Queensland. Aurukun is located north west of Cairns on the western side of Cape York, 12 hours drive (800 km) on largely corrugated gravel roads.

Aurukun has a population of about 1,000.  The Well-being Centre is designed to improve the availability of health services.  It provides a community-based approach to treating addiction and related mental health issues, addressing family violence, reinforcing social norms and facilitating pathways out of treatment to employment and education.  The services offered by the Well-being Centre include assessments, counselling, support, case co-ordination and referrals to other services.  The Centre is being initiated under the auspices of the Royal Flying Doctor Services (RFDS) with the intention of moving to community management over time.  Well-being Centres are also being established in Cape York at Coen, Hope Vale and Mossman Gorge with joint funding by the Australian and Queensland Governments.

The contract for the construction of the Centre together with the two staff houses was awarded to Alan Jenkins and Natalie Gordon Constructions.  Homefab Steel Truss and Frame from Mareeba on the Atherton Tablelands was responsible for the design, manufacture and delivery of the complete kit that included the steel frame with windows, doors, Colorbond® Sandbank steel external cladding for the roof and walls, and fibre cement panels for the internal wall linings.  The contractor managed the site erection of the steel floors and frames, the fixing of the wall and roof claddings, windows and doors, carried out all plumbing and electrical work and the fitting out of the kitchen and bathrooms.

design factors

As the buildings were not required or likely to house a large number of people and were not deemed to have an essential post-disaster function, they were designed for an Importance Level of 2 as required by the Building Code of Australia.  Hence the buildings are required to withstand a wind event with an annual probability of exceedance of 1 in 500.  The site is located in cyclonic wind region C and was assessed as having a terrain category 2.  The buildings are approximately 5 metres high, on a level site and with no other buildings providing shielding.

Applying the appropriate regional wind speed and factors from AS/NZS 1170.2 gives an ultimate limit state design wind speed of 63 m/s, corresponding to AS 4055 housing class C2 (61 m/s).  In tropical cyclones, the window glass may be broken by flying debris and consequently the internal pressure coefficient was determined using the values from AS/NZS 1170.2 for a dominant opening in the windward wall.

The roof battens and truss top chord comply with the requirements determined from cyclic testing of the roof sheeting with the battens.  This set the minimum thicknesses or maximum spacing or maximum spans for these members.  The cladding roll former provided the fixing specification in their literature.

Even though not currently required by the Queensland building regulations, a thermal break between the external cladding and the steel studs was specified by the client.
The Mastotermes Darwiniensis termite is one of the world’s most destructive subterranean termite species and is endemic to northern Australia.  Given this menace, steel framing was the natural choice to meet project durability requirements and most importantly client expectations.

tackling the build

Barry Byrne of Homefab, on winning the project arranged a meeting with the contractor, Alan Jenkins.  The agenda – devise a plan to minimise time on site.  There was no room for error with a site 12 hours travel away.

A steel floor system of C purlin joists on batch galvanised RHS bearers and stumps was adopted as it minimised the amount of concrete required on site. This is a very expensive item in remote locations where you may have to mix on site or truck in from Weipa.  Steel wall frames and trusses were chosen for their speed of construction, strength and termite resistance.

Four trucks were required to transport the material to site:  Truck load 1 – floor framing systems for the three buildings; Truck 2 – steel wall frames and roof trusses for the Well-being Centre; Truck 3 – steel wall frames and roof trusses for the two staff houses; and Truck 4 – the hardware – windows, doors, sheeting etc for all three buildings.

Before loading commenced, a comprehensive job check list was prepared by Homefab and broken down into four truck loads to ensure no components were left behind.  Photos were taken of each load to confirm quality and content.

Thorough planning and development of the design with the client, and preparation of the dispatch check list paid off in dividends.  Work commenced on site on 12 October and in 10 days all the steel frames on all three buildings were installed together with the roof cladding. The finished project of the Well-being Centre and the two staff houses was handed over to the owner on 13 November. A total on site construction time of only five weeks.

Frame supplier: Homefab Steel Truss and Frame