Lookout Tower in Panarbora Nature Discovery Park, Germany
Customer Project
In September 2015, Panarbora nature discovery park opened near Cologne. A highlight of the park is the 131-foot-high, 12‑sided lookout tower made of glued‑laminated timber, which offers visitors a breathtaking view over Bergisches Land.
Structural Engineering |
Structural Planning, Fire Resistance Design Harrer Ingenieure GmbH, Karlsruhe, Germany www.harrer-ing.net Preliminary Structural Analysis Ingenieurbüro Miebach, Lohmar, Germany www.ib-miebach.de |
Construction |
Timber Structures Schaffitzel Holzindustrie GmbH + Co. KG, Schwäbisch Hall, Germany www.schaffitzel.de |
Investor |
German Youth Hostel Association Deutsches Jugendherbergswerk, Landesverband Rheinland e. V., Germany panarbora.de |
Model
A wooden treetop path, 1,772 ft long, is connected to the lookout tower. Dlubal Software customer Harrer Ingenieure from Karlsruhe, Germany, was in charge of the structural analysis and the fire resistance design.
Modeling and Design of the Tower in RFEM
A spatial beam structure model of the whole structure was created in RFEM for the calculation of the lookout tower.
Twelve columns are arranged in both the exterior and interior circles with dimensions of 9.5 / 28 in. To consider the eccentricity of the connections of the supporting girder to the member axis of the columns, rigid-rigid and rigid-release connections were planned.
The construction consists of glued-laminated timber Gl32c with the exception of the round steel crossing diagonals, supporting girders, support rings, and the connections.
Tension member systems with steel grade S 460 (Macalloy and BESISTA types) were used for the round steel diagonals.
The lookout tower is located at an altitude of 1,148 ft above sea level in snow load zone 2a (sk = 0.24 kips/10.76 ft2) and wind zone 1. It is situated in an area outside earthquake zones. The maximum traffic load on the walking routes was set to 1,124 lbs/10.76 ft2.
The design of the wooden elements was performed in the RF‑TIMBER Pro add-on module, the design of the steel elements in RF‑STEEL EC3.
Project Location
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New
Saving Models as Blocks in RFEM 6
In RFEM 6 it is possible to save selected objects, as well as whole structures, as blocks and reuse them in other models. Three types of blocks can be distinguished: non-parameterized, parameterized, and dynamic blocks (via JavaScript). This article will focus on the first block type (non-parameterized).

New
Timber Design | Strength and Stability | Input
The structural system is entered and the internal forces are calculated in the programs RFEM and RSTAB. The program provides access to the extensive material and cross-section libraries.
Timber Design is completely integrated into the main programs and automatically takes into account the structure and the available calculation results. Further entries for the timber design, such as effective lengths, cross-section reductions, or design parameters, are assigned to the objects to be designed. It is possible to select the elements graphically by using the [Select] function.
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How do I define a member as a cantilever and not as supported at both ends for serviceability or deflection design?
- I would like to export nodal support forces of several load cases, load combinations and result combinations into an Excel spreadsheet in RFEM 6. How should I proceed?
- Where can find the option to hide the defined types (for example, design supports or effective lengths)?
- How do I create a user-defined Design Situation with my own chosen load combinations?
- How can I neglect torsion in the steel and timber design?
- How do I perform stability analysis to determine the critical load factor in RFEM 6?
- Where can I find the materials for the corresponding National Annexes in RFEM 6 and RSTAB 9?
- How do I apply wind load on members of open structures?
- Is it also possible to use RF‑/TOWER Loading without the other TOWER add-on modules?
- How does the "Orthotropic Plastic" material model work in RFEM?
- I would like to export nodal support forces of several load cases, load combinations and result combinations into an Excel spreadsheet in RFEM 6. How should I proceed?
Programs Used for Structural Analysis