Power and Water Finds Perfect Purlin Solution

One of the Northern Territory's largest businesses is currently undertaking a major overhaul of its main operational depot, with the help of BlueScope Lysaght.

As the premium provider of electricity, water and sewerage services in the Northern Territory, Power and Water boasts an impressive track record in electricity generation, power transmission and distribution networks, water and sewerage services, rural and remote services, and retail services. With assets in excess of A$1.2 billion and 680 employees, Power and Water plays a major role in the economic and social development of the region.

So when it became necessary to upgrade the Ben Hammond Complex, Power and Water's main operational facility, they turned to the experts. The A$3 million project is being undertaken by leading Northern Territory building firm, Sitzler Bros, in conjunction with consulting engineers Kellogg Brown Root Pty Ltd. It involves the external and internal refurbishment of the site's 6,000 square metre main operational building, which required asbestos removal, and structural modifications to fulfil cyclone code requirements.

The Ben Hammond Complex was taken over by Power and Water in the 1980's, and now comprises voltage testing facilities, workshop stores, and an office complex for technical and administration staff.

Many of the buildings in the complex were constructed in the late 1960's by the Commonwealth Government as part of a railway project, the main workshop building has still train tracks embedded in the concrete slab, explains Andrew Firley of BlueScope Lysaght Darwin. Both the walls and roof of the main workshop were clad with "Box Rib", a profiled steel sheeting coated with a material called Galbestos. Galbestos contains white asbestos fibres.

Over time, the Galbestos roof and wall cladding deteriorated, resulting in water leaks and rust. After conducting a report on the building, Kellogg Brown Root concluded that the cladding was beyond its life expectancy and recommended that the cladding be removed and replaced.

"Sitzler was contracted to undertake the upgrade, which comprised the removal of the Galbestos, the re-cladding of the facade and the upgrade of the building's structural steel work," explains Sitzler Site Manager, Jamie Porrovecchio. "A new glazing system formed part of the re-cladding project, and we also installed a fall arrest system on the roof, which incorporates a cable that runs the full perimeter of the roof, and new roof access platforms."

"Subsequent to the structural work and re-cladding, the project has progressed to include the refurbishment of the interior office space, and addressing the disabled access requirements stipulated in the Building Code of Australia."

As the building's roofing and walling material was being entirely replaced, it was deemed necessary to get the structure up to building code requirements. In order to achieve this, the building needed to be strengthened structurally, which required a new structural design, incorporating new purlins and girts.

That's where BlueScope Lysaght came in. In addition to supplying 30 kilometres of LYSAGHT® Zed and Cee purlins and girts, BlueScope Lysaght provided technical assistance to Kellogg Brown Root, to assist in the optimisation of the purlin system.

"Kellogg Brown Root came up with an initial design, and provided that to BlueScope Lysaght, along with data on numerous different wind load cases and different pressure areas," says Tim Priebbenow, Principal Structural Engineer at Kellogg Brown Root. "BlueScope Lysaght then took this information and optimised the design to achieve the most cost effective solution."

According to BlueScope Lysaght's Greg Clarke, the optimisation offered substantial savings. "We looked at the entire structure of the building and offered an optimisation package to try and reduce costs for the refurbishment," he says. "We looked at the loads and combinations, and found we could drop down purlin gauges in certain areas."

The project commenced in May 2004 and was completed in October 2004. "The project time frame was certainly challenging, particularly because the external work had to be complete before the beginning of the cyclone season," says Tim Priebbenow.

"With BlueScope Lysaght's help we came up with the optimal solution for the client," he adds. "They were very happy with the result."