Pryda Cyclonic Grips (PCGs), specially designed to tie-down roof trusses to wall frames in cyclone-prone areas, are now being used in the construction of 24 villas costing approximately $7.2 million and comprising Phase Two of the Exmouth Escape Resort project in northwest Western Australia.
Each villa consists of a one-bedroom and two-bedroom unit under the one roof. They are being constructed by Prydaâ€™s truss and frame manufacturer WA Spantruss at their East Rockingham facility, before being transported in sections by road to Exmouth.
Pryda assisted WA Spantruss with the roof truss design and specified high capacity PCG90s (Pryda Cyclonic Grips to suit 90mm wall frames) in their construction, along with Surefoot footings for building supports. This project was a collaborative effort between WA Spantruss director David Lewis and Prydaâ€™s Bernard Kennelly, the original design concept dates back to 2013.
Phase One of the resort, comprising 15 villas, an entrance building, restaurant and swimming pool was completed five years ago. So far 16 of the 24 villas (including two earmarked for disabled living) in Phase Two have been sold, with seven assembled on site.
The new Exmouth Escape Resort villas were inadvertently tested under cyclonic conditions when Cyclone Olwyn hit the town in March this year â€“ and came through with flying colours. One of the buildings was still under construction and so the steel base frame was temporarily welded to the bearers while it rode out the storm.
WA Spantruss builds each 10 metre by 10 metre villa in its assembly yard with the roof constructed in two parts, a cap and a lower section.
General Manager Sjaak Van Der Stoep said, â€œWith the 900mm eave overlay, each roof measured 12 metres by 12 metres. The cap footprint is eight metres by eight metres, which we then divide into halves (each four by four metres) for transporting to Exmouth,â€ he said.
The building itself is transported in three sections, one for the one-bedroom and an additional two for the two-bedroom unit.
According to Mr Van Der Stoep, WA Spantruss prefers using Pryda Cyclonic Grips in cyclone-prone areas because they are economical, compact, lightweight and with their rounded edges, extremely safe for installers to use.
Structural engineers and cyclonic specialists like Fremantle-based KSCE Managing Director Tom Vinnicombe, who often acts as a consultant for Pryda fabricators, specify Pryda Cyclonic Grips because they have high capacity in both uplift and shear and are quick and easy to install.
â€œThey also can be used to fix timber or steel trusses to timber or steel frames,â€ he said.
â€œIn addition, Pryda goes to the trouble of publishing design tables and load capacities for these combinations of trusses and frames, which can be designed automatically through Pryda Build software.â€
Mr Vinnicombe said for buildings to effectively resist C3 and C4 cyclonic conditions in these areas, engineers are quick to specify single or double Pryda Cyclonic Grips to ensure roof trusses are securely fastened to their steel frames.
â€œWith Pryda Cyclonic Grips, I can be certain of the testing, quality and the carpentersâ€™ ability to correctly install them, so checking the design and certifying connections is much easier,â€ he said.
Below: Pryda Cyclonic Grips tying down the timber truss to steel wall frame. A common practice in northwest Western Australia.