Safety against earthquake hazards has two aspects: structural safety against potentially destructive dynamic forces and geotechnical hazards related to geotechnical phenomena such as site amplification, landsliding and soil liquefaction. So the correct evaluation of seismic hazard is highly affected by hazard factors due to geological nature and to geotechnical properties of soils. The hazard index based on geotechnical properties of foundation soil assumes a considerable incidence on earthquake ground motion and distribution of damage, as showed by the well known zonation manual "Manual for Zonation on Seismic Geotechnical Hazards", edited by the Japanese Society for Soil Mechanics and Geotechnical Engineering. In past times south-eastern Sicily was shaken by many strong earthquakes. In particular the events of February 1169 and January 1693 destroyed almost completely the city of Catania, causing the death of more than 30 thousand people in the case of the 1693 earthquake. Nowadays the south-eastern area of Sicily, called the "Iblea" seismic area of Sicily, is considered as one of the most intense seismic zones in Italy, considering the past and current seismic history and the vulnerability of civil buildings. The south-eastern Sicily earthquake of December 1990, with a Richter magnitude M=5.4, caused strong damage to civil structures. The acceleration of seismic waves was not only dependent on epicentre distance but was also site dependent, e.g. the recorded acceleration in Catania site was more than twice bigger than the one recorded in a site at the same distance from the epicentre. In order to acquire preliminary elements of knowledge, it was performed an investigation based on the inspection of some historical ecclesiastical buildings of great importance, located in the city of Catania. Then, in order to identify the amplification effects due to the site conditions, a geotechnical survey form was prepared, to allow a semi-quantitative evaluation of the seismic geotechnical hazard for these historical buildings. The Churches upon which the analysis has been carried out are: S. Domenico, S. Vito, S. Sebastiano, S. Giuseppe al Duomo, S. Agata alle Sciare, S. Maria del Soccorso, S. Camillo, S. Maria della Concordia, S. Nicola alla Rena. In figure 1 the map with boreholes location and the Cupola of Saint Nicola alla Rena Church are represented. In addition, to evaluate the foundation soil time-history response for all these ecclesiastical buildings, it was employed a 1-D dynamic hysteretic simplified soil model, considering the non-linearity of soil behaviour (Frenna and Maugeri, 1995). The response of the soil, schematised as a mono-dimensional system with several degrees of freedom and lumped masses, has been evaluated through the integration of the dynamic equilibrium differential equations system with variable coefficients, using the Newmark's numerical step-by-step integration method.
Soil Response Analysis for Some Monumental Buildings During the Earthquake of 13th December 1990
Cavallaro A;
2001
Abstract
Safety against earthquake hazards has two aspects: structural safety against potentially destructive dynamic forces and geotechnical hazards related to geotechnical phenomena such as site amplification, landsliding and soil liquefaction. So the correct evaluation of seismic hazard is highly affected by hazard factors due to geological nature and to geotechnical properties of soils. The hazard index based on geotechnical properties of foundation soil assumes a considerable incidence on earthquake ground motion and distribution of damage, as showed by the well known zonation manual "Manual for Zonation on Seismic Geotechnical Hazards", edited by the Japanese Society for Soil Mechanics and Geotechnical Engineering. In past times south-eastern Sicily was shaken by many strong earthquakes. In particular the events of February 1169 and January 1693 destroyed almost completely the city of Catania, causing the death of more than 30 thousand people in the case of the 1693 earthquake. Nowadays the south-eastern area of Sicily, called the "Iblea" seismic area of Sicily, is considered as one of the most intense seismic zones in Italy, considering the past and current seismic history and the vulnerability of civil buildings. The south-eastern Sicily earthquake of December 1990, with a Richter magnitude M=5.4, caused strong damage to civil structures. The acceleration of seismic waves was not only dependent on epicentre distance but was also site dependent, e.g. the recorded acceleration in Catania site was more than twice bigger than the one recorded in a site at the same distance from the epicentre. In order to acquire preliminary elements of knowledge, it was performed an investigation based on the inspection of some historical ecclesiastical buildings of great importance, located in the city of Catania. Then, in order to identify the amplification effects due to the site conditions, a geotechnical survey form was prepared, to allow a semi-quantitative evaluation of the seismic geotechnical hazard for these historical buildings. The Churches upon which the analysis has been carried out are: S. Domenico, S. Vito, S. Sebastiano, S. Giuseppe al Duomo, S. Agata alle Sciare, S. Maria del Soccorso, S. Camillo, S. Maria della Concordia, S. Nicola alla Rena. In figure 1 the map with boreholes location and the Cupola of Saint Nicola alla Rena Church are represented. In addition, to evaluate the foundation soil time-history response for all these ecclesiastical buildings, it was employed a 1-D dynamic hysteretic simplified soil model, considering the non-linearity of soil behaviour (Frenna and Maugeri, 1995). The response of the soil, schematised as a mono-dimensional system with several degrees of freedom and lumped masses, has been evaluated through the integration of the dynamic equilibrium differential equations system with variable coefficients, using the Newmark's numerical step-by-step integration method.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
