Month: January 2010

  • Uncategorized

    • Damage surveying and seismic vulnerability of churches: the Abruzzo earthquake (Italy)

    Stefano Podestà, Anna Brignola, Emanuela Curti, Sonia Parodi, Alberto Lemme

    The paper proposes some considerations about the seismic vulnerability of the Abruzzo (Italy) churches damaged after the 6th April 2009 earthquake and underlines the topics related to the seismic emergency management and to the temporary supports design for churches. Processing of the data obtained during the post-seismic surveying are thus presented such as the Damage Probability Matrices (DPMs) related to homogeneous macro-seismic area, the vulnerability curves, the distribution of possible and occurred damage mechanisms, together with the correla- tion between the damage index and the safeness of each building. Furthermore a methodology for the design of the temporary supports is proposed and applied to some churches located in Paganica (L’Aquila)

    For this paper is available an extended abstract after the text in Italian

  • Uncategorized

    • Effect of the new Italian Technical Regulations for Constructions on the seismic resistance of steel frames

    Edoardo M. Marino, Marco Muratore

    The Technical Regulations for Constructions of 2008 (D.M. 14/01/2008) are the final step of the development of the new seismic code which has taken place in Italy in the last five years: the O.P.C.M. 3274 in 2003, the O.P.C.M. 3431 and D.M. 14/09/2005 in 2005 and, finally the D.M. 14/01/2008 in 2008. This code has introduced important innovative seismic design practices for building structures, such as performance based design, use of strength criteria based on limit state method instead of allowable stress method, definition of high and low ductility structures, a new and very articulated framework for the evaluation of the design seismic force, capacity design criteria, etc. In this paper the regulations provided by the new Italian seismic code for steel moment-resisting frames and for concentrically braced frames are analysed and compared with those of the old Italian seismic code (D.M. 16/01/1996). The outcome of the comparison depends on the structural type, however the obtained results show that often lateral strength demand stipulated by the new code is less conservative.

    For this paper is available an extended abstract after the text in Italian

  • Uncategorized

    • Finite Element Approaches for the Dynamic Analysis of Seepage

    Riccardo Stucchi, Annamaria Cividini, Giancarlo Gioda

    Two finite element approaches for the dynamic analysis of seepage flows are discussed here. This represents the first step of a study on the effects of earthquakes on retaining or embedded structures in saturated granular soils. The equations governing the flow of a liquid within a porous skeleton under an acceleration field varying with time are recalled first. Then they are combined in two differential equations that, reduced to their weak form, lead to a finite formulation of the problem in terms of discharge velocity. Due to the relatively large number of nodal variables, and to the iterative structure of the time integration algorithm, this approach requires a non negligible computational cost. Then a second approach is presented, based on some simplifying assumptions, where the pore pressure represents the nodal variable and that adopts a direct time integration scheme. The finite element programs implementing the two formulations are finally applied to the solution of a bench mark problem presented in the literature. The numerical results permit drawing some conclusions on the accuracy of the two approaches that will guide in the choice of the most convenient of them in extending the study towards the analysis of coupled two-phase problems.

  • Uncategorized

    • Recent application of seismic isolation systems in Italy

    Alessandro Martelli, Massimo Forni

    At present there are over 10,000 structures in the world that are protected by means of seismic isolation (SI), energy dissipation (ED) and other seismic vibration passive control (SVPC) systems and devices. They are located in more than 30 countries. Italy is now fifth at worldwide level (after Japan, the P.R. China, the Russian Federation and the USA) and is first in Western Europe. In the last years, however, there was a large increase of the number of the applications completed and, especially, of those in progress or under design. This was due at first to the new Italian seismic code, enforced in May 2003 by Ordinance Nr. 3274 of the Prime Minister (mostly as a consequence of the San Giuliano di Puglia tragedy during the 2002 Molise and Puglia quake), which freed and simplified the adoption of the SVPC systems; a second cause was the 6.3 magnitude Abruzzo earthquake of April 6, 2009. The new applications in Abruzzo recently made Italy fourth at worldwide level for the number of isolated buildings. Moreover, Italy remains among the worldwide leading countries for the number and importance of bridges and viaducts protected by the SVPC systems (which are over 250) and also for the manufacturing of the latter (especially of the SI ones) for applications to all kinds of structures abroad. This paper summarizes the state-of-the-art of applications of anti-seismic techniques in Italy, with particular attention to the most recent ones of SI to buildings.

    For this paper is available an extended abstract after the text in Italian