Page 33 - Advanced Design Examples of Seismic Retrofit of Structures

Example of a Two-Story Unreinforced Masonry Building Chapter 2 25

(A) (B)

(C) (D)

(E) (F)
FIG. 2.10 Examples of collapse of surrounding walls. (A) Collapse of the wall and scattering of
bricks which indicates poor quality of brickwork. (B) Overturning from the base. (C) Collapse of the
wall and scattering of bricks. (D) Overturning from the base; note the wall’s buttresses were inef-
fective because they were not secured at the base. (E) Removed debris from the collapse of the sur-
rounding wall in a school building after 2003 Bam earthquake; note the school building is standing.
(F) Overturning from the base. (Permission from DRES.)

in URM walls, and openings can change the pattern of cracks throughout URM
walls. Fig. 2.13 shows some examples of in-plane cracks of URM walls in past
earthquakes.

2.4.6 Damage in Walls Supports

Insomecases,masonrycolumnsattachedtoURMwallsareusedintheperipheral
walls to act as the wall’s supports. By reducing the free length of the walls, these