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2013-09-04

Lookout Tower on Rügen Island, Germany

The highlight of the 4,659-acre natural heritage area on the Baltic Sea island of Rügen is the 131-foot-high "Nest Tower".

The tree tower gives visitors a breathtaking view of the landscape from a height of over 262 ft.

Construction of the Tree Tower

The structure of the tower consists of an outer ring made of 12 vertical glulam beams. They are arranged with rotational symmetry and set up with an angle difference of 30° each, thus forming a polygonal, spatial structure.

The columns are supported by means of steel girders on single foundations. The tree tower is stabilized by a close-meshed net of diagonal steel members as well as horizontal ring structures.

The upper third of the tower was fitted with 12 glulam arcs to make it look like an eyrie. The arcs are fastened to the cantilevered steel platform at the top and to the glulam columns at the bottom. The outer diameter of the timber tower is approximately 79 ft; in the area of the "eyrie" it is about 118 ft.

Connected to the observation tower is a 1,367-yard-long walkable treetop path that winds through the treetops at a height of 13 to 56 ft. The path is also the entrance to the tower. In order to reach the viewing platform at the top of the tower, visitors have to enter the 656-yard-long spiral structure inside the tower.

The platform consists of steel cantilevers protruding outwards that connect to the timber columns, and between them longitudinal timber beams with planking.

Structural Engineering Structural Engineering and Timber Construction of Tower
WIEHAG GmbH
Altheim, Austria
www.wiehag.com

Structural Engineering Office
Ing.-Büro Wolf GmbH, Passau, Germany
Architect Architect Josef Stöger, Schönberg, Germany
stoeger-koelbl.de
Client Erlebnis-Akademie AG, Bad Kötzing, Germany
www.eak-ag.de


Project Specifications

Model Data

Number of Nodes 1349
Number of Members 1970
Number of Load Cases 10
Number of Load Combinations 156
Number of Result Combinations 4
Total Weight 229.512 tons
Dimensions (Metric) 34.408 x 34.408 x 40.500 m
Dimensions (Imperial) 112.89 x 112.89 x 132.87 feet
Program Version 8.01.01

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