Zur Tragfähigkeit der Sandstein-Treppen im historischen Provinzial-Arresthaus in Mainz - Standsicherheitsnachweis in einem Denkmal

The load carrying capacity of historic sandstone staircase structures in the former "Provinzial-Arresthaus" in Mainz.

Subject of this paper are in-situ-tests of the load carrying capacity of historic staircase structures in the former "Provinzial-Arresthaus" in Mainz (which was a prison). The building, located in the centre of the governmental area of Mainz, is of prime importance from the architectural and town-historic point of view. The entire complex, built in 1906, consisting of a court house and the prison, the first price of a competition won in 1903 by the famous Architect Paul Bonatz (1877—1956), was in use as such until 2002 and after that it was empty for years. In the middle of the year 2009 the renovation of this building into a modern office and administration building started. The facade and the staircases were listet as historic monuments. It is important to emphasize that such alteration may occasionally cause heavy interventions into the historic stock of the structure in order to ensure the load carrying capacity for the forseen usage by means of strengthening, if the calculations do not prove the existing capacity as sufficient.
Not only for listed historic monuments, but rather all historic buildings designated for a further usage it must be the goal in terms of economic efficiency to reduce retrofitting measures on the existing structures as much as possible.
For the particular building the calculative proof was not possible since information about material and construction were not available. For this reason the experimental check was a proper alternative method. Three of four staircases were listed, the fourth staircase was designated to be demolished and gave a good chance to determine the real load carrying capacity up to the complete collapse. The goal was altogether to keep the three staircases as they are without any retrofitting measures and to keep them unaffected during the tests as much as possible.