Derek Dubout

The company I work for, Ian Bennie & Associates, specialises in testing facades in-situ on buildings. Sometimes this process is relatively easy, and we build a suction chamber on the indoor side of the building. Unfortunately, this approach has many limitations. It's difficult to span over multiple floors and a suction box test just doesn't simulate the effects of fluctuating wind in combination with rain on the outside face of a building. This means we are often required to install a pressure chamber on the external face. I use PowerCADD throughout the process of designing, organising and implementing such projects. The following drawings and photos show the story. This project involved placing a 3.75m wide by 7.5 m high (12' x 25') pressure chamber on the outside of a building in the centre of Sydney, Australia. The chamber had to be completely supported from within the building and, as it was an existing building being refurbished, everything had to be either craned from the street or carried up in the elevators.

Here I've detailed the location on the building and basic connection to the building structure.

Part of the process involves co-ordination of cranage sub-contractors and city permits for road and footpath closures. This is a simple sketch of the site to help clarify our requirements with all the other parties involved.

Details of the main structural elements for connecting the chamber to the building. These details are for our own in-house use as we fabricate all the components ourselves.

Here are the main bottom supports inside the building ready for installation of the chamber. The following two photos show the main structure of the chamber installed.

From this point we build a scaffold inside the chamber and clad the back with ply wood panels. I'm sorry I haven't got any photos of the craning process, I was too busy making sure it all actually fitted on the building.

Once the testing is complete I write my report. This is a diagram included in the report showing the location of devices used to measure displacement of the facade under load.

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