Tendon-Systems for Seismic Protection of Historic Block Masonry Structures

• Applicant: Professor Dr.-Ing. Uwe Dorka
• Subject Area: Structural Engineering, Building Informatics and Construction Operation
• Term: from 2014 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 250867227

Antique structures made of large stone blocks (e.g. Greek temples) were very robust, even against earthquakes. Today, most of them are ruins and we know very little about their performance under extreme earthquakes. This is important though, if we want to preserve them for the future and in case earthquake retrofitting may be necessary.The precursor project provided important basic knowledge about the performance of columns through hybrid simulations that lead to the development of realistic numerical models for them. It also demonstrated the effectiveness of the so-called "Tendon System" for seismic retrofitting of such structures. This "seismic control" concept stabilizes the motion of the column through a tendon in its centre, which produces re-centering forces only during an earthquake. This system does not change the original structural concept (which is also part of our cultural heritage, not only the architecture) and it is almost entirely reversible. Both are important conditions for any retrofitting performed on historical structures.The knowledge gained and methods applied during the investigations on the columns will now be used in the continuation of this project, in order to analyze the behavior of the block structure in the architraves and gables. This should enable us to model the complete structure realistically under earthquakes. For this, a block-for-block model will be developed, which not only models the mechanical interaction between blocks, but also considers the influence of the block pattern, which imposes certain motion pattern through its geometry. Hybrid simulation (an online combination of numerical model and specimen) turned out to be an excellent tool for the investigations on the columns and will be used again to produce realistic data to validate the numerical model.In addition, the Tendon System will be investigated further, this time including devices that can control the forces in the Tendons.In the end, this project shall provide a method for a realistic simulation of the behavior of antique structures made of large stone blocks under earthquakes, and allow us to decide on the need for adequate retrofitting technologies (especially the controllable Tendon System).It would thus make a substantial contribution to the protection of our cultural heritage against one of the most dangerous natural hazards.

• DFG Programme: Research Grants