Scaffold construction for restoration of the church spire in Kerpen

In order to restore the church spire of the St. Martinus community in Kerpen a work scaffold was required.This scaffold was part of the entire building measures with a contract volume of approximately € 850 000.

A particular feature of this property was that the scaffold supporting frame had to be mounted onto the spire without the pressure bracings commonly used for scaffold supporting frames.

A canvas cover was used to lessen the impact of wind forces on scaffold construction.

Construction was carried out using a module scaffold, shaped like a 16-edge polygon with dimensions ranging from approximately 40 m – 60 m, while the 8-edge polygon measured approximately 60 m – 70 m.

Structural Analysis 

A three-dimensional supporting frame was calculated using RSTAB.The additional modules RSKNICK, RSIMP, EL-PL were also utilized.   

Structure generation

AutoCAD was used for the initial modeling.The data was then imported into RSTAB using the DFX-interface, where the cross-sections were assigned the corresponding materials.The tail hinges of the bars were simulated with the non-linear RSTAB-tail hinges according to vendor specifications.

Estimating Load

Windload was estimated according to EC 1 / DIN 1054.For this part, the approximation for a 16-edge and an 8-edge polygon was estimated and compared to the shape of a circular cylinder.The crucial load group resulted from a combination of the net weight combined with the maximum windload (for load groups the partial safety factor used for scaffold construction is always 1.5).Using the RSTAB-function for load generation simulations, an alternative simulation incorporating the different windloads was created with little additional labor.

Stability Analysis

The smallest buckling shape was estimated using the additional module RSKNICK. Using the module RSIMP, this buckling shape was used to automatically generate imperfections in RSTAB. The load groups net weight, windload and imperfections were combined for the calculation according to the 2nd order theory. Subsequently the module RSTAB EL-PL was used to confirm the simulation both elastically and plastically.

Companies involved in construction:  Bauherr Katholische Kirchengemeinde  St. Martinus  Stiftstrasse 6  D-50171 Kerpen  Bauunternehmer Geistert Gerüstbaulogistik GmbH  Am Nienhaushof 29  D-47134 Duisburg  www.geistert.de

Planning / Static Calculations: Ing.-Büro Klimpel  Am Gartenkamp 31  D-44807 Bochum  www.IB-Klimpel.de  Software Ing.-Software Dlubal GmbH Am Zellweg 2 D-93464 Tiefenbach www.dlubal.de

This is a screenshot of the CAD-program.