BLÁHA, JIŘÍ1; PANÁČEK MICHAL2; CHAMRA, SVATOSLAV3; KOVÁŘOVÁ, KATEŘINA4; RAFL, TOMÁŠ5

1 Ing., Ph.D., Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, CET Department, blaha@itam.cas.cz

2 Mgr., National Technical Museum, Prague, Czech Republic, Architecture Department, mpanacek@yahoo.com

3 Ing., CSc., Czech Technical University in Prague, Czech Republic, Geotechnics Department, chamra@fsv.cvut.cz

4 Mgr.MBA., National Technical Museum, Prague, Czech Republic, Geotechnics Department, katerina.kovarova@fsv.cvut.cz

5 Ak.mal., National Technical Museum, Prague, Czech Republic, Architecture Department, tomas@rafl.cz

After the controversial discussion which accompanied a recent repair of the Charles Bridge in Prague an interdisciplinary team was given the task of summarizing the technical, technological and conservation requirements for the selection and processing of the replacement stone intended for ashlar masonry repairs. Geologists, structural engineers, construction historians, conservationists and restorers joined together to give their views on the relevant intensity of interventions, the replacement stone quality and also the parameters of processing by craftsmen. Methodical guidelines should define the necessary level of adequate historical, technological and structural surveys and, subsequently, propose an optimal procedure for laboratory tests and for the following repair processes of a particular structure. A focus on the influence of the finishing tools to the look and durability of the stone surface is among the most innovative aspects. Concurrently the practical usefulness of the methodology has been tested on appropriately selected cultural heritage monuments during their repairs, or other interventions.

Keywords: sedimentary rocks, ashlar masonry, stone processing, traces of tools, material provenance, heritage conservation and preservation