Hyperbolic wooden construction
Stiftung der Sparkasse Hemer vertreten durch Landesgartenschau Hemer 2010 GmbH
Birk Heilmeyer und Frenzel

The look-out tower was built for the regional garden festival „Landesgartenschau“ in Hemer 2010. The 23 m high tower is also the end point and peak of the “Jacob’s ladder”, a stair-shaped sculpture leading up to the crest of the hill. The shape of the tower, which is diverting towards the top, reacts to the local circumstances; the forested hill Jüberg, the urban centre line and a 360-degrees view. The construction has been designed as hyperboloid of reverse inclined groups of members. It consist of 240 straight timber members of Siberian larch (glued laminated timber) with a cross section of 8 x 8 cm. According to the static stress, the number of single slats per member group diminishes from the bottom to the top. A large-mesh structure has been designed by inclining two reverse planes of members. Linked to the horizontally arranged steel rings, it forms a triangular structure of static efficiency. This timber slat shell transfers all affecting vertical and horizontal loads. Hence, internal bracing constructions are not necessary. The supports in the lowest plane consist of six individual rods, which are reduced to five in the next level, then four, three, and two rods. This allows for an increasing panoramic view the higher you get to the observation deck. The Jüberg Tower is the first of its kind, being a real timber rod hyperboloid.