Page 28 - Advanced Design Examples of Seismic Retrofit of Structures

20 Advanced Design Examples of Seismic Retrofit of Structures

(A) (B)

(C) (D)

(E) (F)
FIG. 2.6 Examples of the effects of construction quality on seismic performance of URM build-
ings. (A) Lack of mortar in head joints and excessive mortar thickness in bed joints after Zarand
earthquake, 2004. (B) Neglecting code’s regulation about distance of shear bars in a confined
masonry building after Zarand earthquake, 2004. (C) Lack of reinforcement in horizontal tie in a
confined masonry building which resulted in shear failure. (D) Detachment of bricks due to lack
of mortar cohesion after Zarand earthquake, 2004. (E) Poor construction quality of vertical tie in
a confined masonry building. (F) Poor construction quality of vertical tie in a confined masonry
building. (Permission from DRES.)
2.4.1 Damage Due to Out-of-Plane Failure of URM Walls

A review on the damage of URM buildings due to previous earthquakes shows
that URM walls as the main load-bearing structural elements are very vulner-
able to out-of-plane seismic actions. Nonetheless, with simple considerations,
e.g., clamping the walls at the top, great improvements in this behavior can be