Avanto Architects: http://www.avan.to/
TOWER, WOOD, LANDMARK
Korkeasaari Zoo (Helsinki) and Wood Focus Finland organised an architectural competition for the students of architecture at Helsinki University of Technology, with the assignment of designing a ten-metre-high view tower out of timber for the Zoo.The free form was motivated by the natural setting; it follows the surrounding stone wall and skirts around a group of birches.After the workshop, the architect laminated full-scale test pieces of battens, which form the basket-like gridshell. He studied whether the pre-bent battens tolerate bending and twisting to a sufficient degree as to allow their use in a construction of this type. When the laminated timber resisted twisting he resorted to steaming, a traditional method in boatbuilding. The effect of surface treatment with linen oil-based wood balm on moisture content was determined by moisture tests and the durability of the joints was proved by tension tests.Finally in June-August 2002 the tower was erected by an international group of eight students of architecture. The structure behaves like an eggshell; even when the gridshell, which consists of over 600 joints, is punctured it withstands the load. The load bearing structure consists of 72 long battens with a section of 60mmx60mm that are bent and twisted on the site from seven pre-bent types. As the tower has no structural protection against weathering, it is treated with a linen oil-based wood balm with UV-protection.
Project Name : Kupla – Helsinki Zoo Lookout tower
Location: Korkeasaari Zoo
Design Team : Ville Hara/ Wood Studio workshop
Competition: Student competition 1999, 1st prize
Period of design: 2000-2002
Area: 82 m2
Commander, user: Korkeasaari Zoo (Helsinki)
Developer: PWD (Helsinki City Public Works Department) Construction Management
Architectural design: HUT Wood Studio/ Ville Hara, architect SAFA
Structural engineering: DI Hannu Hirsi, DI Lauri Salokangas /Nuvo Engineering
Photographs: Jussi Tiainen http://www.jussitiainen.com/
