Page 195 - Handbook of Materials Failure Analysis

4 General Presentation of the Vulnerability Index Method 191

factor is assigned to each one. There are four classes for stone masonry buildings: A,
B, C, and D; and three for reinforced concrete buildings A, B, and C.
Several studies have been dedicated to the CNR-GNDT method, in some coun-
tries in South America, Europe, and North Africa, such as:
Gent Franch et al. [2], in their study, the Italian CNR-GNDT vulnerability index
for masonry buildings was modified in order to obtain a vulnerability index I 3GA that
considers the properties of confined masonry shear-wall buildings. In Chile, the
modified Italian method was applied considering a sample of 24 confined masonry
buildings with three and four storeys built during the last 25 years for social housing
programs.
Vicente et al. [7] applied methodology considered a hybrid technique in the
evaluation of the vulnerability of the entire historic city center of Coimbra (Portu-
gal). The vulnerability index formulation proposed is based essentially on the
GNDT approach, for the vulnerability assessment of residential masonry buildings.
This methodology is based on post-seismic damage observation and survey data
covering a vast area, focusing on the most important parameters affecting building
damage which must be surveyed individually. Overall vulnerability is calculated
as the weighted sum of 14 parameters used in the formulation of the seismic
vulnerability index.
Bezzazi et al. [8] have adapted a scale of vulnerability from the CNR-GNDT
method, where a retiming of the weighting coefficients is performed, to better match
with architectural characteristics of local buildings in northern Morocco. The authors
have even proposed fragility curves for this typology building.
A large-scale vulnerability assessment using two methods was conducted for
buildings of Tunis by Mansour et al. [9], for which few data were available. Vulner-
ability methods inspired by the EMS98 concepts and the Italian GNDT concepts
were modified and applied to pilot-scale buildings located in the downtown zone
(Habib Bourguiba Avenue) and in the old zone (Medina).

4 GENERAL PRESENTATION OF THE VULNERABILITY
INDEX METHOD
An accurate assessment of the tank vulnerability to earthquakes is long, laborious,
and expensive, it is better to perform an initial study which can be only qualitative,
to determine if a more thorough approach is needed, which also allows to thinning
down the problem. This approach, allows evaluating a presumption of vulnerability
(that is to say, a pre-diagnosis) that can be done by an engineer trained in seismic
construction, without assistance of an experienced engineer of design office in engi-
neering. It includes the study of available archival material, if possible a search for
information from individuals who participated in the construction of the project, a
statement of vulnerability factors in an external and internal visual inspection on site,
and operation of grids field surveys, covering architectural design, bracing system,
and the site.