Przyczyny techniczne awarii rusztowań. Cz.4

The paper deals with technical aspects which influence the load-bearing capacity and the operation of scaffolds during a construction. The complexity of the problem is presented in the example of failure of a modular scaffold which, after assembly, did not satisfy the conditions for the ultimate limit state and finally it failed due to the wind action. Next the author presented the following technical problems: formation of the main structure of scaffolds, bracing sets, foundation of scaffolds, load-bearing capacity of the anchors, the accuracy of assembly, technical state of the elements, loads acting on scaffolds. The impact of these factors on the possibility of scaffolds failure is illustrated with an example of a facade scaffold. For this scaffold the effort and the natural frequencies were determined in the following situations: the structure with perfect geometry, the structure with imperfections, the scaffold with perfect geometry and taking into account the uneven ground subsidence, and the scaffold with imperfections and uneven subsidence included. The numerical analysis showed that the scaffold does not comply with conditions for the ultimate limit state and that the most important for the capacity of the structure and its proper functioning is the accuracy of the scaffold assembly.