Seismic Vulnerability of a Historical Masonry Building: A Critical Comparison of Analytical MethodologiesMarco Boscolo Bielo
, 2020, doctoral dissertation
Abstract: In these last twenty years a new sensibility for the seismic themes around buildings has emerged from a cultural and technical point of view. As a result of some earthquakes happened in Italy, the promulgation of technical codes has accelerated and, essentially, the standards of Eurocodes were accepted. Consequently, also in the field of historical buildings, a set of specific guidelines have been issued.
In the current state of art, designers are faced with many methods of calculation which the technical codes offer for the assessment of the seismic vulnerability of historical buildings. Designers can use simplified or complex approaches which assume different starting hypothesisto obtain different results.
This thesis aims to investigate the various aspects that the designer meets during the study of the static behaviour of an historical building and the assessment of its seismic vulnerability. A study case is also proposed which regards a Venetian Villa of the XVIth Century located in “Riviera del Brenta” near Venice, with a critical comparison of the results obtained by the application of the various methods of calculation.
The thesis begins with an outline of the historical development of seismic technical codes in Italy and shows how the sensibility has developed in the Italian culture. In particular it is illustrated the difference between the approach of the legislation "a posteriori" (where a “patchy zoning” was generally performed after the occurrence of earthquakes), and the probabilistic approach based on the peaking ground acceleration expected in every Italian site.
The Second and the Third Chapters contain the analysis of the current seismic legislations and in particular the guidelines for historical buildings.
The Chapter 4 provides a general discussion on the masonry and the definition of the mechanical parameters. There are many critical aspects relating to a characterization of models which can realistically represent the historical masonry. They are due to a heterogeneity of variables such as, for instance, the mechanical parameters, the physiological behaviour, the connections, etc.
In the Chapter 5 the basic concepts of seismic behaviour of historical buildings are discussed. In particular the Pagano’s classification of masonry buildings is illustrated with special regard of the following factors: stiffness of horizontal structures; efficiency of “masonry beams”; efficiency of intersection between walls.
From the Chapter 6 the analysis of the study case begins. Here we can find the description of the Venetian Villa (historical evolution of the buildings, description of geometrical characteristics, structural behaviour, etc.
In the Chapter 7, the first level of analysis is performed for the study-case. The method of calculation is contained in the guidelines for historical buildings. A critical discussion of the results is also illustrated.
In the Chapter 8 is performed a linear kinematic analysis based on various possible kinematic mechanisms identified through the study of cracking and the lacks of the structural
The Chapter 9 shows a non-linear static analysis (pushover) for the study-case which refers to two limit behaviour models: the first one with infinitely rigid diaphragms and efficient masonry beams; the second one based on infinitely flexible diaphragms and weak masonry
beams. The results are compared and critically discussed.
In the same way the Chapter 10 and 11 perform a linear static analysis and a linear dynamic analysis for the two models of the Chapter 9, so the results can be compared.
In the last Chapter a general discussion about all the results of the performed analysis is conducted. Here the work points out the conceptual limits of each method of calculation and the possibility of use related to the objectives which must be reached. Finally some design indications related to the results of the analysis are illustrated.
Found in: osebi
Keywords: Seismic, Vulneraility, Analitical, Methodologies
Published: 02.07.2020; Views: 1210; Downloads: 20
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