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    • Analisi di rischio e incertezza: l’uso dei metodi Monte Carlo per i rischi naturali

    Daniela Molinari

    Risk analyses always involve uncertainty which depends on the knowledge analysts have of the phenomenon they are dealing with. So, in order to use risk analyses results in a more transparent, aware and justified way, it is important to characterize and quantify this uncertainty. Unfortunately, in the field of natural risks, present analyses are mainly deterministic and do not allow uncertainty representation. The aim of this study is then proposing and testing Monte Carlo methods, which have already been adopted in other research fields, as tool for probabilistic risk analyses. In particular, the suggested method develops the seismic «Renewal Process» in a new methodology which allows to quantify and characterize both input and output parameters uncertainty. A case study, regarding the Garfagnana region, has validated the methodology. The added value of the proposed method is its transferability in the analyses of other natural hazards

    This paper is available in Italian only.

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    • Il metodo dinamico per la verifica sismica di edifici esistenti: il caso dell’ospedale «Cristo Re» in Roma

    Cristiano Algeri, Paolo Panzeri, Giuseppe Rossi

    The seismic response of existent buildings can be conveniently performed using dynamic methods. This kind of methodology implies a reliable calculation pattern which is validated by dynamic tests on the structure. In this paper a specific analysis of a strategic masonry building – a civil hospital in Rome – is proposed. All the experimental tests were carried out on the structure without altering the functionality of the building, which was always in full operation during the tests.

    This paper is available in Italian only.

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    • Analisi sismica di edifici esistenti in muratura con metodo dinamico: applicazione a Villa Faule (SI)

    Maria Luisa Del Savio, Luciano Galano

    In this paper a general method is given to evaluate the collapse seismic load of existing masonry buildings. The method is based on numerical analyses in which both linear and nonlinear models are used to evaluate the seismic response of the masonry assemblage. The structure is first idealized by a F.E. model to investigate the stress patterns produced by the static loads, then a simplified nonlinear dynamic model is used to predict the collapse seismic load. In addition, the F.E. model is useful to identify some mechanical parameters of the masonry and to establish the accuracy of the simplified approach. To this aim the first two modal shapes of the building are used. To exemplify the general methodology here discussed an application is presented for Villa Faule, to be found in the Tuscany countryside in the neighborhood of Colle di Val d’Elsa (Siena). The Villa Faule was built at the end of XVIII century and is representative of many similar country houses located in the same geographic zone. Considering the dilapidated state of the walls, of the timber floor slabs and of other architectural elements, in recent times a design was approved to strengthen and to rehabilitate the building. The subject of this study is the strengthened building because the large-scale numerical models are more reliable for such types of structures. The results showed that both the procedures were useful to investigate the structural problem. The F.E. model furnished a good prediction of the masonry stresses under vertical loads and predicted the modal shapes of the structure; at the same time it revealed that the simplified model was accurate. The nonlinear simplified method gave a prediction of the seismic ground acceleration intensity to be applied to achieve the building collapse. To this purpose the structure was subjected to the N-S acceleration record of El-Centro (Imperial Valley’s earthquake, 1940). The results showed that the value of the collapse peak ground acceleration was equal or more than 2.75 m/s2.

    This paper is available in Italian only.

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    • Strutture prefabbricate in c.a. in zona sismica: stato della pratica costruttiva italiana e principali problematiche di progettazione

    Gian Michele Calvi, Manuela Filippetto, Davide Bolognini, Roberto Nascimbene

    The work presented here is the starting point of a two-year numerical and experimental research programme, funded by the Department of Civil Protection and developed at the European Centre for Training and Research in Earthquake Engineering (Eucentre), the main goal of which will be the evaluation of the seismic local and global response of RC precast structures. The present article concerns a preliminary overview of the main design issues following the recent development of the code requirements.

    This paper is available in Italian only.

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    • Il ruolo della fascia di piano nel comportamento sismico degli edifici in muratura

    Bruno Calderoni, Emilia Angela Cordasco, Pietro Lenza

    This paper deals with the role of the spandlers in the seismic behaviour of the masonry building. Particularly the seismic performance of masonry walls in their own plane have been analyzed by mean of non-linear static analyses performed on schemes of equivalent frames. Different geometrical and structural configurations of the spandlers have been considered and the corresponding capacities in coupling the piers have been deepen too. Both beams and columns have been modeled considering lumped plasticity at the ends of the elements. The results obtained confirmed the very strategic role of the spandlers in the seismic capacity of the masonry building

    This paper is available in Italian only

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    • Valutazione degli effetti di amplificazione sismica in piccoli bacini sedimentari per studi di pericolosità sismica locale a scala regionale

    Massimo Compagnoni, Floriana Pergalani, Daniela Di Bucci, Giuseppe Naso

    Parametric analyses for the evaluation of the local seismic response, in small sedimentary basins, are here presented. These analyses have been performed through 1D and 2D models, with the aim to point out a quick methodology for the evaluation of local seismic hazard of sedimentary basins and to include these effects in studies of seismic hazard at regional scale.
    The results of this study consist of specific tables where the amplification factor Fa is shown as depending on seismic zones, soil classes and thickness range of the deposits. The Fa related to the lithological effects was calculated for period ranges of 0.1-0.5 s, 0.5-1.0 s and 0.1-2.5 s. Moreover, for the period range 0.1-0.5 s, a specific value of DFa has been calculated to take in to account the geometrical effects of the basin. The Fa ranges allow has to define an increasing scale of the local seismic hazard suitable to single out areas characterized by different geological exposure to local seismic effects. These areas should be further analyzed at a more detailed scale.

    This paper is available in Italian only

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    • Influenza delle Tamponature sulla statica dei telai in c.a. in zona sismica

    Dora Foti, Massimiliano Borgia

    This paper describes a model able to evaluate the effect of masonry panels on reinforced concrete frames subjected to a seismic action. The panel is modelled as an equivalent diagonal element with a bilinear constitutive relation. The efficacy of the model is verified with an hysteretic model which considers some fundamental characteristics of masonry subjected to a seismic action (transitory phase between elastic and elasto-plastic behaviour, stiffness and strength decay, reduction of the hysteresis cycles due to the opening and closing of the cracks). This study shows that the presence of masonry panels causes a different distribution of the seismic action that usually concentrates in the lower floors (with accumulation of the damage in these levels) and the whole structure keeps in the elastic field.

    This paper is available in Italian only.

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    • Experimental definition of shear deformation and strength for masonry panels

    Anna Brignola, Maurizio Ferrini, Sergio Lagomarsino, Francesco Mangone, Stefano Podesta'

    The paper shows the results obtained during experimental campaign of diagonal compression tests in Tuscany, in which a significant number of masonry panels were tested. The aims of this research are mainly two. On the one hand the authors compare medium values of shear strength and shear stiffness varying the knowledge level proposed in the OPCM 3431 code (LC1, LC2 and LC3). On the other hand, the authors verify shear strength and stiffness range value, given by OPCM 3431 code for masonry typology most recurring in Tuscany (Italy).

    Available in Italian only