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Petrini, V.
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Petrini, V.
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- PublicationRestrictedDetection of local site effects through the estimation of building damages(2003)
; ; ; ; ; ; ; ; ; After the Umbria Marche seismic sequence of September–October 1997, an extensive microzoning study was conducted, from October 1997 to May 1998, to detect the zones where the ground motion was amplified because of local geological and geomorphological settings. The goal of the investigation was to return amplification coefficients to local authorities for the post-seismic reconstruction and repairing of pre-existing buildings, by examining the seismic behaviour of the most damaged 60 villages. The analysis consisted in the application of well known computer codes and the results were arranged as reference table, used to assign the amplification coefficients to the rest of damaged localities. The present study has the aim of evaluating the accuracy of that methodology, following a completely different approach. The actual damages, detected by an aerial photo interpretation, are compared to the theoretical damages estimated through empirical curves, obtained from the analysis of recent Italian earthquakes. This approach was reliable enough to calibrate the results of the microzoning study and appropriate when an immediate assessment of the damage is required, to assign funds and estimate the amplification zones, that need to be investigated in finer detail.203 3 - PublicationRestrictedMeasuring the seismic vulnerability of strategic public facilities: response of the health‐care system(2000)
; ; ; ; ; ; ; ; ; ; ; Strategic public buildings must be made as efficient as possible to allow for emergency operations, like search and rescue activities, taking care of victims, and evacuation. Looks at strategic public buildings as part of urban and regional systems. Addresses factors such as physical vulnerability to a seismic event, location, accessibility, interaction with the soil, links with other public facilities, and the way the latter are used under normal conditions. Considers whether public facilities can continue providing their service under stressful conditions, even when a certain degree of physical damage has been suffered by structures or by medical equipment. The health-care system has been chosen as a key test field: the result is a framework which helps assess the vulnerability of hospitals serving an area prone to seismic risk.140 3 - PublicationOpen AccessAn application on Geographic Information Systems connected to Expert System(European Center for Geodynamics and Seismology (ECGS), 1995)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;The studies urban areas directed at the definition of seismic risk, raise the problem of the seismic vulnerability assessment of construction properties that require the estimation of the tendency to damage of a plurality of buildings. Very often one comes upon buildings that have been constructed in former epochs without the use of seismic codes and generally built in masonry. The leads to the search for procedures for vulnerability assessment, based on the rapid acquisition of information on existing buildings, which must furnish a sufficiently reliable assessment of the seismic damageability, generally without the possibility to refer to very sophisticated models. In previous works, assessments of seismic vulnerability have been effected using surveys transferred on National Project for Seismic Prevention (GNDT) sheets (Zonno and Ducarme, eds, 1992). These works have been realized using capes systems in order to treat with the uncertainty of the data. However, the analyses that only refer to GNDT sheets, are limited to single buildings, ideationally understood as isolated. An alternative and maybe complementary attempt is to assess the vulnerability of buildings in a global structural context using Geographic Information Systems to mapping the urban system, integrated with the surveys transferred on COOT sheets. The main characteristics of the building and the structural context, indices of a major or minor damageability, have been individuated, but it is difficult to define a rapid procedure for the assessment of seismic vulnerability. The idea was to use an expert system to codify a basis of the presently acquired knowledge and to apply it automatically on the basis of the results obtained by processes of space analyses calculated by GIS. On the basis of the data obtained with GNDT sheets, the vulnerability of the building can be assessed independently from the structural context (intrinsic vulnerability). The availability of data on the space distribution of the adjoining buildings permits an assessment on the effective vulnerability that takes into account the influence of the structural context. With relation to other works effected on the argument, the proposed system automatically assesses a large quantity of geocoded data either in geometry and in the structure of the components. In particular, in this work the seismic vulnerability assessment of the buildings is effected through the Geographic Information Systems PC Arc-Info connected with the Expert System Shell Nexpert Object, starting from the methods used by the GNDT of the National Council for Research (CNR) (Benedetti and Petrini, 1984; Baldi and Corsanego, 1987) and integrating the effects of anisotropics of the structural behaviour and context (Grimaz, 1992-93).79 61 - PublicationRestrictedExpert System for Damage Assessment of Buildings in Seismic Areas(European Center for Geodynamics and Seismology (ECGS), 1996)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;The analysis of damage on buildings affected by an earthquake allow to trace back to the defects of the structural system and the imperfections of the constructive elements with reference to the best or worst behaviour in case of seismic action. As a matter of fact the tendency of buildings to be damaged, also defined as seismic vulnerability, is strictly connected with their geometric-constructive characteristics. The damage appears as "effect" of the phenomenon that has its "cause" in the seismic action. Once the characteristics of the system are defined, it is possible to reconstruct the 'cause-effect' relation between seismic action and damage. These relations can be obtained through survey of damage caused by recent earthquake. However this methodology reveals a series of problems. The various quantities applied must be expressed with indices that allow to synthesize complex and articulated scenarios exhaustively; although the damage is a quantity that can be directly assessed by description, it is difficult to measure, as its quantification should be representative for all aspects connected with it (physical, economic, functional, social, etc.). The level of the seismic action must be expressed by a parameter that is an index of the event's destructive capacity and in direct correlation with mechanical quantities (acceleration, velocity, energy, etc.). The vulnerability is an entity able to characterize the more or less accentuated predisposition of the structures to suffer damages independently from the intensity and direction of the seismic action. In this work, subjects concerning seismic action and vulnerability shall not be dealt with, as they have already been investigated in previous works [see Grimaz S., 1992 - Cella F. 1994 and 1995]; in the following the problem of damage quantification shall therefore be explored.80 6 - PublicationOpen AccessDistribuzione nazionale della vulnerabilità media comunale(CNR-Gruppo Nazionale per la Difesa dai Terremoti, Roma, 2000-05)
; ; ; ; ; ; ; The vulnerability assessment on large areas was carried out on residential buildings adopting a statistical approach that has been developed for this purpose. In fact, even though the method for evaluating single buildings vulnerability is quite well defined, it cannot be applied to large areas, not only because it would cost too much in money and time to survey each building, but also because the result would be useless at this scale, where the information needed for decision making is less detailed. Census data are a primary source in this case: they cover homogeneously the whole country though the information they provide permits only to estimate the total number of buildings, the total volume and a poor classification in terms of age and few typological parameters. The collection and review of available data regarding previous buildings vulnerability surveys performed by GNDT and census archives has been organised inside a database for the calibration of buildings vulnerability functions in the investigated area. The vulnerability evaluation for all Italian municipalities has been performed as a weighted mean of the average vulnerability index for each census classes.89 614 - PublicationOpen AccessA structural analysis in seismic archaeology: the walls of Noto and the 1693 earthquake(1995-11)
; ; ; ; ; ;Guidoboni, E.; SGA, Storia Geofisica Ambiente, Bologna, Italy ;Riva, P.; Dipartimento di Ingegneria Civile, Universitá di Brescia, Italy ;Petrini, V.; Dipartimento di Ingegneria Strutturale, Politecnico di Milano, Italy ;Madini Moretti, A.; ENGI.CO., Engineering & Consulting, Milano, Italy ;Lombardini, G.; Facoltà di Architettura, Università di Ferrara, Italy ;; ; ; A crucial problenl for seismic archeology is how to recognize seismic effects and how to date them. On an experimental basis. we proposed that the problem be reversed, and that we begin at the other end: i.e. by analyzing already known seismic effects on ancient structures, testified by written sources. to be able to .calibrate>> the types or possible observations and any subsequent elaborations. The choice of the walls of Noto was suggested by the fact that Noto was abandoned following the earthquake of l693 (I,= XI MCS. Me 7.5) which had already been studied in depth as part of an ING research programme (1988-92). Moreover, just after recent research, this event proved to be reconstructed with a high quality standard. Photogrammetric measurements were made on several parts of the town walls to plot a numerical model aimed at ascertaining specific aspects of the earthquake damage. An estimate of the ground acceleration during the earthquake has been attempted via non-linear finite-element analyses of a building located by the main city gate. The analyses show that. in order to obtain the building vault collapse, a ground acceleration of 0.5 to 0.7 g had to be reached during the earthquake. This result, typical of a strong earthquake such as the one of 1693, proves that an approach based on finite element analysis and a sound engineering judgment Inay be systematically applied to historical earthquake sites to obtain some estimates of ground acceleration in historical earthquakes. On the whole, this work aimed at starting up the second development phase of the great event of 1693 of which the macroseismic erfects are known. In the meantime, some possibilities of tackling structural analyses in seismic archaeology are being explored.212 259 - PublicationRestrictedThe SERGISAI procedure for seismic risk assessment(2003)
; ; ; ; ; ; ; ; ; ; ; The European project SERGISAI developed a computational tool where a methodology for seismic risk assessment at different geographical scales has been implemented. Experts of various disciplines, including seismologists, engineers, planners, geologists, and computer scientists, co-operated in an actual multidisciplinary process to develop this tool. Standard procedural codes, Geographical Information Systems (GIS), and Artificial Intelligence (AI) techniques compose the whole system, that will enable the end user to carry out a complete seismic risk assessment at three geographical scales: regional, sub-regional and local. At present, single codes or models that have been incorporated are not new in general, but the modularity of the prototype, based on a user-friendly front end, offers potential users the possibility of updating or replacing any code or model if desired. The proposed procedure is a first attempt to integrate tools, codes and methods for assessing expected earthquake damage, and it was mainly designed to become a useful support for civil defense and land use planning agencies. Risk factors have been treated in the most suitable way for each one, in terms of level of detail, kind of parameters and units of measure. Identifying various geographical scales is not a mere question of dimension; since entities to be studied correspond to areas defined by administrative and geographical borders. The procedure was applied in the following areas: Toscana in Italy, for the regional scale, the Garfagnana area in Toscana, for the sub-regional scale, and a part of Barcelona city, Spain, for the local scale.181 1