Parametric Analysis of “Zollinger Type” Ribbed Timber Shells

The following article presents the study and further development of the roof system developed and patented by Friedrich Zollinger in 1920. The so-called Zollinger construction system is based on short timber components ‐ lamellae, connected by a bolt and a form of decking only for covering purpose. By developing the micro step joint, an increase in joint stiffness can be achieved. In addition, by applying and activating a load-bearing roof covering, a further increase in system stiffness can be achieved and demonstrated. Especially with regard to large spans, the increase of the stiffness and reduction of the deflection becomes inevitable against the background of an economic feasibility. Based on the analysis of the historic Zollinger system, it is possible to evaluate potential for improvements in terms of system stiffness as well as contemporary design, development and manufacturing. Due to the large number of different influencing factors, the system was modeled as a parametric master model. In this, a closed process cycle can be developed from the geometric definition, to the static analysis and to the derivation of the computer-aided manufacturing data. In the present study especially the exact recording, description and modeling of the stiffness and feasibility of the connection details “lamella‐lamella” and “lamella‐planking” was investigated. A parametric finite element model can be used to determine the stiffness parameters as a function of the fasteners used and the spacing of the fasteners. Staple connections are used as the main means of connection between the lamella and the planking. The implementation of the staple connections in the finite element analysis was carried out using spring parameters, which are determined in the course of the development. The analysis and optimization of the connection stiffnesses is presented against the background of an economical structure development. By using digital planning methods and interfaces, a contemporary way of working is presented. In addition, a contribution is made to digitalization in the construction industry.