Carter Holt Harvey: A triumph for LVL on so many levels.  The Hudson Brown project in the Auckland CBD is a large block of city apartments. Located near the old railway building, its recent construction is a sign of this area's new lease on life. Based on an interesting and complex split-level design, construction of each apartment block building required careful engineering and project management. Hyspan Structural LVL and Hybeam Engineered I-Joists by Carter Holt Harvey were used throughout to solve many of the structural design issues. The Hudson Brown project is a complex of over 130, one to three-bedroom apartments, divided into five buildings, all of different design and structural requirements. Mathew Erskine-Shaw of Stephen Mitchell Engineers is the structural engineer overseeing the project's structural design and for him, the challenge of the project was the architectural layout and the complex geometry of the split-levels. Each building is independent and built above a podium. Construction for the most part is a combination of reinforced concrete lower levels and laminated veneer lumber (LVL) structural elements for the upper levels. Originally, the design of the upper levels of the five blocks was for conventional timber construction. However, because of the size and quantity of services that had to run through the numerous apartments this was not a viable option. The Project Manager on the job, Graeme Harvey of Dominion Constructors Limited in Auckland, approached Carter Holt Harvey and together they came up with an alternative solution utilising Hyspan and Hybeam in the roof and mid-floors to allow for the large penetrations. Mathew and Graeme accepted the solution from both a structural and construction viewpoint and are very pleased with the results. Each of the five blocks is typically built from a timber uppermost floor and roof. 300mm deep Hybeam was used to span up to 5.2 metres for both floor joists and rafters, supported onto load-bearing timber walls between apartments. The depth of the Hybeam for the rafters was chosen to accommodate the maximum size of web holes. Hyspan was used as trim beams around stair voids and for boundary joists to simplify the connections to the joists and rafters. The Hyspan trimming joists spanned between inter-tenancy walls to eliminate the need to design for load-bearing elements onto the floor, and cantilevered over the breezeway to support the upper floor and roof. It also served to block a potential fire path through the floor depth. The lack of roof space posed a construction challenge as it was difficult to run services through the space available in the low-aspect skillion roof. Graeme was able to run ventilation and other services through the Hybeam rafters: "Cutting holes for ventilation was easier with LVL, we could get holes big enough to get the ducts through the Hybeam I-Joists. Our primary reason for selecting the product was to vent air out through the roof space and maintain the required 6 metre separation between fresh and exhaust air." Graeme's team found the LVL products fast and efficient to put in place and this helped with speeding up construction on this huge development. Begun in May 2004, the entire complex is due to be finished in November this year, with all of these city-dweller apartments already sold. This 'corporate' city-residential building construction is storming ahead with already another couple of similar projects underway by the old railway building. 
For further information contact:
Carter Holt Harvey
Phone: 1300 658 8...
Fax: 02 9468 5....
Web: www.chhwoodproducts.com.au
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