LYSAGHT BONDEK® Makes Light Work Of Carpark Challenge

LYSAGHT BONDEK® profiled steel decking became an integral part of the solution when parking space pressures confronted a large Brisbane organisation.

The challenge involved adding an extra level and associated ramps to an existing two level car park, the upper level of which had been originally intended for conversion to office space.

"The existing structure was built on piers," Bonacci Group Brisbane principal, Peter Gill said about one aspect of the structural engineering challenge.

"That imposed strict weight limits on what we could use for the additional car parking level."

Steel framing and a composite slab built with 3,500 square metres of BONDEK® steel decking specified in 1.0mm thickness with pre-painted BRITEWITE® soffit created an exceptional result which has pleased the building owner.

Companies involved in the project included BAC Group Architects, Fitzgerald Formwork and Construction and ADCO Constructions.

Despite budget constraints, Dennis Beitz, Director of BAC Group Architects, was determined to design a car park which would look as good as it performed. What eventuated has been described as a showcase of structural steel decking.

"Other buildings on the site have prominent steel features such as screens and there was steel detailing on the existing structure," Dennis said. "It was important to carry that standard through to the new level, even though we were primarily switching to steel because of the weight savings it would make possible.

"Because it was a steel structure we felt that BONDEK® decking would give a better result than could be achieved with conventional formwork, even if weight considerations for the slab had not been important."

LYSAGHT BONDEK® decking is the original steel formwork system that revolutionised concrete construction. It is made from DECKFORM® zinc-coated high-tensile steel which was developed by BlueScope Steel specifically for the steel decking market and is backed by a BlueScope Steel warranty and nationwide technical support.

With a coverage width of 590mm the sheets are fast and easy to install, with less handling required than for conventional formwork. Ribs at 200mm centres create a safe working platform with slip resistant embossments.

As well as functioning as a composite slab to save on concrete and reinforcement costs, BONDEK® also provides strong fire resistance.

BONDEK® sheeting specified with a pre-painted BRITEWITE® soffit uses BlueScope Steel’s world leadership in steel coating technology to help achieve maximum lighting efficiency in car park and basement areas.

The sheeting is supplied with a tough protective plastic overlay which covers the BRITEWITE® soffit to protect it during the construction phase, but which can be easily stripped when props have been removed after a concrete pour.

BlueScope Lysaght personnel visited the car park construction site and provided technical support during the installation of the BONDEK® sheeting which was carried out by a team of four from Fitzgerald Formwork and Construction, supervised by foreman Scott Kimber.

"We took ten working days to complete the major slab and about the same time for the curved ramps, which were smaller but quite detailed." Scott said. "Because of the lack of reach of the site crane we used a forklift with its tines covered in carpet to place some bundles of the BONDEK® sheets where we needed them.

"BlueScope Lysaght delivered the material cut to size in 9.6 metre lengths which covered three bays. The curved ramp sections meant one or two sheets had to be cut for every bay, but that was done easily with a 1mm cutting blade on a 100mm grinder. At the engineer’s request we also fastened every sheet to the I-beams each 300mm."

Before the first concrete was poured, all on site put much effort into making sure the outcome would be a high quality finish.

"Taking that precaution established standards which the formworkers could apply throughout the entire job," architect Dennis Beitz said.

"We inspected and re-inspected to confirm the laps and ends of the BONDEK® sheet spans were sealed effectively to prevent any slurry runs. There was no extra time added to the building program, because once the slab had been poured and then the props were removed, there was no need to paint the soffit.

"This was one of the first applications of BONDEK® sheeting with the BRITEWITE® pre-finish in Queensland and based on experience gained on the car park project BlueScope Lysaght has revised the documentation and advice it provides to formworkers handling the product.

"We are very happy with the outcome. The BONDEK® structural steel formwork with BRITEWITE® on the soffit is an expression in steel and a strong feature of the building. I’d use it again," Dennis said.

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