Page 446 - Advanced Design Examples of Seismic Retrofit of Structures
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392 Advanced Design Examples of Seismic Retrofit of Structures
FIG. 6.1 Total collapse of adobe houses during the Ziarat earthquake in 2008. (Permission from
Dr. Hashmat Lodi [2].)
to those “engineered” buildings that cannot meet the design codes’ require-
ments. An example is shown in Fig. 6.2 in which an adobe building with lower
vulnerability and a collapsed RC building are compared after the 2003 Bam
earthquake.
Many years of research have succeeded in developing improved construc-
tion techniques and the related codes for building design and construction has
been adopted in some countries, for example, Peru; however, these efforts are
not directly applicable to existing nonengineered constructions, which represent
a real seismic risk [3]. Considering that there are too many structures of this kind
throughout many developing and underdeveloped countries and a majority of
their residents have little financial affordability, seismic retrofitting of these
buildings should be taken as a priority rather than reconstruction. It is obvious
that the proposed retrofitting technique should be simple, feasible, and econom-
ical, as well. Therefore, it is imperative to find low-cost retrofitting alternatives,
capable of providing these buildings with sufficient confinement and integrity
as to withstand severe earthquakes without collapse [4]. In the case of old build-
ings, which are usually of historical value, the implemented methods should
also have no conflicts with the appearance and character of these buildings.
Unlike other more commonly used structural systems—that is, brick
masonry, steel, and reinforced concrete structures for which regulations exist
for their seismic retrofit—a lack of retrofit codes, or even construction design
codes in many countries, makes retrofitting of nonengineered buildings more
challenging. In the absence of robust design procedure for seismic retrofit of
these buildings, reliance on experience, available tests results, and, more impor-
tantly, engineering judgments plays a significant role. Apart from the fact that
nonengineered buildings cover a large spectrum of structural systems, for exam-
ple, stone masonry, adobe buildings, etc., the construction details and materials
of each particular structural system can be very divergent in different regions.