The Interdisciplinary Activity For Seismic Risk Analysis In A Mediterranean City
Free (open access)
S. Grasso & M. Maugeri
The seismic risk analysis evaluation in the Mediterranean area is one of the main tasks for the preservation of Cultural Heritage and for the sustainable development of Mediterranean cities. The Mediterranean area is characterised by medium-high seismic risk, so that earthquakes are the major cause for the destruction of monuments and residential and industrial buildings. A case history of the seismic risk analysis is presented for the city of Catania (Italy), which has been destroyed many times in the past by the 1169 earthquake (XI MCS), 1542 earthquake (IX MCS), 1693 earthquake (XI MCS), 1818 earthquake (VIII MCS) etc., which caused several thousands of deaths. Fault modelling, attenuation laws, synthetic accelerograms, recorded accelerograms, site effects are considered for the evaluation of the seismic action. Vulnerability of the physical environment related to the presence of cavities and to seismic induced landslides and liquefaction is analysed, with special reference to the new modelling of such phenomena and to the application of the models to given areas. The soil-structure interaction has been analysed for some geotechnical works, such as shallow foundations and retaining walls, by means of physical and numerical modelling. Vulnerability of monuments and buildings has been evaluated with the aim of estimating the seismic resistance required to resist the seismic action given by the earthquake scenario. For the mitigation of seismic risk, structural improvements of R.C. buildings with different methodology and techniques are proposed, as well as guidelines for the strengthening of the buildings. The seismic risk of the city is not a summation of the seismic risk of each building, because the vulnerability of the urban system plays an important role on the seismic risk evaluation of a given city. To this aim the vulnerability of road infrastructures, lifelines and urban framework have also been analysed.