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In Forest Lake Gardens, timber is the new steel These days it is not enough for a retirement village to be simply comfortable. Residents and those considering the move expect all the amenities and even the 'wow' factor. Forest Lake Gardens in Hamilton New Zealand now sports a recently completed recreational facility, a large wedge-shaped building that once might have required a steel structure but was constructed economically and quickly using Hyspan and Hybeam by Carter Holt Harvey. | The residents of Forest Lake Gardens wanted a building with common amenities - a gymnasium, pool, kitchen, lounge and dining areas. This common building was originally to be attached to the apartment complex but the village owner decided that completion would take too long. The time frames were tight. | 
| Instead, Jeff Lukin of Arrow International Ltd in Hamilton was brought in to project manage a stand alone structure for the common amenities that would also serve as a focal point for residents. The aim was to have prospective residents drive down the entrance toward the village and on seeing the facility, say 'wow'. Lukin was briefed to produce the 'wow factor' but the residents wanted it ?nished by Christmas, so that the festivities could be held in the common area. Time became a key driver for Lukin. The building entered the design process, and the concept of a triangular or 'wedge-shaped' structure with a novel roof alignment cantilevering to a sharp end was developed. Lukin considered how to achieve such a structure and considered steel. However, due to the sky-rocketing price of steel in New Zealand and a shortage of steel fabricators they also looked at a steel and timber combination. The use of LVL meant considerable cost savings for the project which came from the ability to pre-fabricate the LVL components off-site while the steel part of the structure was erected. This meant that the structure could be put up in the fastest possible time and within the original budget for the building. "My best estimate is that the Hyspan and Hybeam solution for the roof would have saved us 25% on time on the structural frame," says Lukin. According to the engineer on the project, Alex Murahidy of Holmes Consulting Group, Hyspan and Hybeam were well suited to the unique shape of the building. The structural form, being a departure from a conventional rectangular building, required an innovative design approach. Lateral stability was afforded through a combination of structural systems. A masonry core, at one end of the building and enclosing the kitchen facilities, extended to the underside of the roof. At the other end and along one side of the wedge, steel portal frames were employed. The roof was constructed from lengths of 600 x 63 mm Hyspan over spans of up to eight metres. For spans greater than this, doubled up Hyspan was used following the straight forward procedures outlined in the Carter Holt Harvey technical literature. HJ300 Hybeam purlins were cut between the rafters and a plywood diaphragm with membrane roo?ng applied over these. Connection to supporting steelwork and masonry walls was readily achieved using simple bolted proprietary systems. Architecturally, there were many features that drew on the LVL and steel combination. Structural elements became architectural features with the steel used in the portal frames expressed between glazed openings. A novel water feature for discharging rain water was incorporated into the design. Water is directed down the incline of the roof and collected in a sump at the sharp end of the building formed using LVL trimming beams cantilevered over a steel 'V-frame'. Water is then ejected spinning and at high speed through a large hole in the base of the sump. "LVL is a fantastic medium," says Murahidy. "Large clear spans across amenity areas were able to be easily achieved using Hyspan. The sizeable plywood roof diaphragm was fastened directly to the HJ300 Hybeam purlins discounting the need for additional timber blocking." Wide eaves along the sides of the building were achieved by cantilevering the LVL rafters up to two metres off the steel frames. The end of the LVL was cut to suit the slim curved pro?le required by the Architect. For project manager Lukin, the other advantage of the LVL was that after completing the LVL structure the builders could move immediately into putting the plywood straight on and closing the building quickly. Says Lukin, "Closing a building in New Zealand is a major consideration because of the rainy conditions and the requirement to ?nish the closing before beginning the internal lining of a building." Also, because of the lightweight nature of the LVL beams, there was little cranage involved and only lightweight cranes were needed. Says engineer Murihidy, "Steel would have required more blocking whereas the LVL option meant the rafters and purlins were already in place and the plywood diaphragm only had to be attached to the LVL sub-structure." The residents of Forest Lake Gardens have got their 'wow factor', and all within time and budget. 
For further information contact:
Carter Holt Harvey
phone: 1300 658 828
fax: 02 9468 5890
web: www.chhpanels.com.au
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