Page 193 - Handbook of Materials Failure Analysis

2 Seismic Vulnerability 189

water storage elevated tank in order to test the reliability of the developed method.
The tank chosen is built on piles in Tizi Ouzou municipality, classified as average
seismicity area. Finally, the main conclusions and the lessons learnt from the expe-
rience are given in Section 6. A fairly rich bibliography is given at the end of the
chapter.

2 SEISMIC VULNERABILITY
The seismic vulnerability of a structure is a quantity associated with its weakness in
the case of earthquakes of given intensity, so that the value of this quantity and the
knowledge of seismic hazard allows us to evaluate the expected damage from future
earthquakes [3]. The evolution of the vulnerability study in the world gave birth to
several methods of assessing damage to the individual buildings, structures, build-
ings, urban and historical centers. They differ from one another in terms of cost,
in used facilities, and in precision. But there is, to our knowledge, no method of seis-
mic evaluation of water tanks.
The systemization of these vulnerability assessment approaches has been devel-
oped by many researchers and therefore differs due to varying levels of dependence
of the following factors: nature and objective of the assessment, quality and avail-
ability of information, characteristics of the structure stock inspected, scale of assess-
ment, methodology criteria, and degree of reliability of the expected results. Because
of these differences, the coherence and consensus regarding the classification is
always a contentious issue. Various methods for seismic risk assessment have been
implemented in countries with strong seismicity; they were ranked in ascending
order of complexity, such as:
The simplified method developed by Zacek [4] for use by architects written in
1993, is a rapid and inexpensive method for assessing a presumption of buildings vul-
nerability to earthquakes by visual inspection. It can be used by nonexperts to identify
potentially dangerous buildings. The review duration is about 30 min by construction.
This method, presented as a guide, was used in Pointe-à-Pı ˆtre (Guadeloupe) and
Fort-de-France (Martinique) to assess the vulnerability of buildings.
A second method is the one proposed by the working group “vulnerability of
existing buildings” of the French Association for Earthquake Engineering (AFPS)
[19]. This method is applicable to buildings constructed since 1960. Two levels
of assessment are covered. The first is a qualitative approach and the second in a
quantitative verification. For the qualitative approach, an evaluation grid is filled
in which a penalty coefficient is assigned to the different vulnerability factors. These
coefficients are used to calculate a coefficient K varying from 0 to 100. Depending on
its value, it is concluded of a presumption of structure vulnerability, ranging from
high vulnerability to very low vulnerability, considering intermediate levels.
For the ATC 40 method [20], designed for reinforced concrete constructions, pub-
lished in the United States in 1986 by Applied Technology Council, is innovative com-
pared to conventional approaches. Vulnerability is assessed by a nonlinear static