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2021-12-15

Bell Tower in Bleibach, Germany

An extraordinary bell tower has been built in Bleibach in the Southern Black Forest Nature Park, Germany. The structure, with a height of approximately 111.5 ft, has a triangular floor plan and consists mainly of cross-laminated timber (CLT).

There is a viewing platform at a height of about 46 ft. Upon request, you can look out over the surrounding valleys and the peaks of the Black Forest mountains.

The engineering office of Wirth Haker PartmbB from Freiburg, Germany, was responsible for the structural analysis of the tower structure. The engineers used RFEM and the RF‑LAMINATE and RF‑DYNAM Pro - Natural Vibrations add-on modules for the structural analysis and design.

Structure

The tower shaft, the bell chamber, and the spire form the three main components of the tower. The ground plan forms an equilateral triangle with side lengths of about 22 ft. The side walls consist of cross-laminated timber elements with a thickness of 7 7/8 inches, made of silver fir. They rest on a reinforced concrete ring foundation with about 11-foot-high foundation walls and an 18-inch-thick floor slab. The walls are anchored in the foundation by means of cast-in steel rod anchors as well as slotted plates and dowels.

You can reach the viewing platform (at a height of approximately 46 ft) by climbing 60 steps and crossing twelve intermediate landings. The level of the viewing platform has a height of about 9 ft. Above this, the belfry extends over two levels (2 x 9.5 ft). The upper end is the spire in the shape of a three-sided pyramid with a height of 36 ft.

The triangular shape of the tower and the wall elements made of CLT with their glued longitudinal and transverse layers ensure high stiffness and dimensional stability of the structure. In addition to the static loads, the dynamic loads due to the swinging bells are absorbed well.

For fire protection, fire resistance class F30 was required. This was used in the fire resistance design of all structural components, including the steps. The vertically arranged facade formwork made of Accoya wood ensures the timber protection of the construction. This wood, chemically modified with acetic anhydride (acetylation), is particularly resistant to wood-destroying fungi and insects as well as weather conditions.

Location
Parish St. Georg
Schulstrasse 2
79261 Gutach-Bleibach im Breisgau
Germany
Investor Röm.-kath. Kirchengemeinde Mittleres Elz- und Simonswäldertal
Pfarrei St. Georg - Bleibach, Germany
www.kath-semes.de
Architecture WerkGruppe1
www.architektur3.de
Object and Structural Design Wirth Haker PartmbB
Beratende Ingenieure
ing-wh.de
Construction Holzbau Baumer GmbH
www.baumer-holzbau.de


Project Specifications

Model Data

Number of Nodes 339
Number of Lines 396
Number of Members 60
Number of Surfaces 43
Number of Load Cases 4
Number of Load Combinations 9
Number of Result Combinations 2
Total Weight 138.376 tons
Dimensions (Metric) 7.067 x 8.160 x 35.931 m
Dimensions (Imperial) 23.19 x 26.77 x 117.88 feet
Program Version 5.27.01

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