Page 447 - Advanced Design Examples of Seismic Retrofit of Structures
P. 447
Examples of Nonengineered Buildings Chapter 6 393
FIG. 6.2 An example comparing damage to a properly constructed “nonengineered” building and
an improperly constructed “engineered” building. (A) An adobe building with slight damage.
(B) A collapsed RC frame; the structural deficiencies include, but are not limited to, passing column
bars outside the beam bars in the connection zone, wrongly-located split point in the column; very
poor construction quality of split point in terms of bonding of concrete; and low-quality concrete.
((A) Photo taken by Mohammad Yekrangnia. (B) Permission from Dr. A.S. Moghadam.)
This variety results in different behavioral characteristics, failure modes, and
different performance levels during earthquakes. An example of two different
failure modes caused from different construction details of adobe buildings in
two different parts of the world is shown in Fig. 6.3. As a result, a particular
retrofit scheme which suits a building type in one region may not be beneficial
for the same structural system which is found in another part of the world; hence
retrofit methods and especially details for each structural system is subjective to
a specific details practiced in a particular region. Consequently, the contents of
this chapter are presented in the form of major successful experiences from sev-
eral countries that contributed to seismic retrofit of nonengineered buildings.
Among the various structural types which are categorized as nonengineered
buildings, adobe buildings constitute one of the most abundant and vulnerable
construction types. Adobe as the main construction material of the early con-
struction was available in the region and easily worked by local masons. Adobe
has many promising features for construction in arid regions; it provides effec-
tive thermal insulation, the clay-type soil from which adobe blocks are made is