Hyperboloid

Hyperboloid

HEMER (DE) - For a long time now, the regional garden shows organized by Germany's federal states have functioned not as festivals of floral glory, but as remedial instruments in town planning and landscape architecture. In Hemer (North-Rhine Westphalia) the focus was on the transition between the built-up area and surrounding countryside, which is now marked at the end of the town's principle axis by a 23-metre wooden tower visible for miles around.

Designed by Birk and Heilmeyer Architects, the tower is constructed as a hyperboloid formed by groups of wooden battens inclined in two directions around the structure. It comprises a total of 240 straight lengths of Siberian larch (glued laminated timber) with a cross-section of 8×8 centimetres. To match diminishing loads, the number of battens per group decreases from bottom to top. Two layers of battens are inclined in opposite directions, creating a loose-knit mesh. Combined with horizontal steel rings, the result is a sturdy triangular structure. This wooden outer shell bears all vertical and horizontal loads, avoiding any need for additional inner supports. At the lowest level, each group of battens has six members, of which five extend to the next level, then four, three, and finally, two. In this way, visitors climbing up to the observation platform are offered increasingly open views of the landscape. (Ursula Baus)