Theme Lecture – Documentation and investigation of behaviour of two historical arch bridges
The Plaka bridge (partially collapsed in 2015) and the Konitsa bridge were constructed in the same mountainous region of Greece (Epirus) in mid-nineteenth century. Both have suffered damage due to explosives (the first, by the German Army (in 1945), the second, by the Ottoman Army (in 1913)) and they were repaired using concrete (either plain or reinforced). The partial collapse of Plaka bridge allowed for the construction system of the bridge to be identified (construction materials, double central arch, systems of timber grids, foundation). The bridge was modeled, taking into account the results of in-situ and in-lab investigations and observations, and its collapse was interpreted.
On the other hand, exhaustive in-situ and in-lab investigations of Konitsa bridge have put in evidence the similarities of the bearing structure of the two bridges. Furthermore, modeling and numerical analyses allowed for the non-collapse of the bridge due to the explosives to be interpreted and for the efficiency of the 1913 repair to be assessed.The two case studies show that the documentation of the structural system, as well as the regular inspection of historical bridges subject to adverse environmental conditions are prerequisites for their preservation.