Page 37 - Advanced Design Examples of Seismic Retrofit of Structures

Example of a Two-Story Unreinforced Masonry Building Chapter 2 29

(I) (J)

(K) (L)

(M) (N)

FIG. 2.13, CONT’D (I) Stepped-diagonal cracks around door with shear-sliding behavior.
(J) Stepped-diagonal cracks with shear-sliding behavior. (K) Stepped-diagonal cracks in a classroom
with shear-sliding behavior. (L) Stepped-diagonal cracks with shear-sliding behavior. (M) Stepped-
diagonal cracks with shear-sliding behavior. (N) Stepped-diagonal cracks with shear-sliding
behavior. (Permission from DRES.)
2.4.7.2 Vertical Cracks at Corners
Vertical cracks at corners usually occur at walls intersection and have flexural-
tensile nature. If these cracks are not preceded by out-of-plane failure of walls
(Section 2.4.1), they are rarely a threat to stability of masonry buildings.
Fig. 2.16 shows some examples of vertical cracks at corners of masonry walls.

2.4.7.3 Various Cracks Combined With Previous Cracks
Compound cracks, which are a combination of vertical and diagonal cracks at
the walls’ corners, are very common in URM buildings. If diagonal cracks