Flagpoles at the Goldenen Reiter

Flagpoles at the Goldenen Reiter

In spring 2014, a temporary art project was to be installed on the historic flagpoles at Neustädter Markt in Dresden. Due to missing as-built documents and uncertainties regarding the mechanical properties and condition of the existing materials on the one hand and the exact design of the anchorages on the other hand, a computational verification of the stability was not possible. Load tests on the mast tips and the anchor rods in the base in which the masts are fixed were to provide clarity on the load-bearing capacity.

The test of the load-bearing capacity of the anchor rods was carried out with 1.5 times the tensile load from the maximum mast load to be considered. This corresponds to twice the safety against the governing mast loading for the service load case and six times the safety against the governing loading. All four anchors were examined on each of the two bases. An auxiliary structure had to be designed and manufactured in advance in order to be able to enter the loads experimentally. This consisted of two hydraulic cylinders that could be controlled in parallel, two load cells, a load-distributing steel plate and the original anchor nuts, which were pressed upwards by the piston stroke of the hydraulic cylinders. The changes in length of the tie rods were recorded using inductive displacement transducers (IWA). On the basis of the recorded deformation state, it was possible at the same time to be able to assess any possible damage that might be imminent. Since the mechanical properties of the tie rods are difficult to capture, the transition point from elastic to plastic deformation was defined as the failure criterion.

The rehabilitation of the flagpoles was completed in November. Nothing now stands in the way of the art project.