Brandschutztechnischer Nachweis von historischen Stahlstützen am praktischen Beispiel

摘要

The Wiesendamm 22-30 industrial complex in Hamburg was established in 1917. The building was designed for the Heidenreich & Harbeck machine factory and in the following years was expanded, rebuilt, partially deconstructed and converted in its usage; in 1937 the structure of the building was substantially expanded. It is planned to re-use the building as a public theatre. In the fire safety strategy and in alignment with the building authorities, the minimum fire resistance for the building structure (including the steel columns) was set to 90 minutes. It soon became apparent that any form of passive fire protection of the columns should be avoided. Therefore all parties agreed that the steel columns should be subjected to a natural fire design scenario. The challenge lies in particular in the fact that more than 70 columns have to be considered in case of fire. There are ten different cross-sections, six different buckling lengths and six different loads. Furthermore, the columns are distributed throughout the building and thereby subjected to different thermal influences in case of fire. Finally, the applicability of the stress-strain relationship as well as the thermal material characteristics of the steel DIN EN 1993-1-2 from 1917 in the event of a fire is questionable. In the course of an economical approach, the steel columns were grouped with respect to the expected thermal exposure and subjected to corresponding fire simulations using the field model FDS. Regarding the existing mechanical stress on the columns, the most affected columns were identified, assigned to the groups of thermal influences and measured/modeled under fire conditions. To validate the above fire engineered approach, samples were taken from the columns and examined regarding their strength and stress-strain-relationships at both normal and high temperatures. Accompanied by a literature research, the basic assumptions of the structural fire design simulations could be determined. The article describes the chosen procedure, calculations and associated test results.