Page 38 - Advanced Design Examples of Seismic Retrofit of Structures

30 Advanced Design Examples of Seismic Retrofit of Structures

(A) (B)

(C) (D)
FIG. 2.14 Examples of damage to walls’ support. (A) Severe cracking and detachment of the sup-
port from the wall. (B) Partial collapse of wall’s support due to a combination of the wall’s out-of-
plane movement and compressive forces. (C) Cracking of wall’s support. (D) Damage at the base of
wall support. (Permission from DRES.)

propagate and reach the vertical cracks at the walls’ corners, a large part of the
walls can freely fall out from the building. Examples of compound cracks in
masonry buildings are shown in Fig. 2.17.

2.4.8 Damage in Ties in Confined Masonry Buildings

Experiences from past earthquakes have shown that horizontal and vertical ties
in confined masonry buildings play an important role in seismic performance
improvement of these buildings compared to that of the corresponding uncon-
fined masonry buildings. However, poor construction quality of ties in these
buildings can result in ineffectiveness of the ties. The most common damage
in CM buildings is caused by poor construction quality of ties, poor concrete
quality, poor connection of horizontal and vertical ties, poor connection
between the ties and the surrounding walls, and inadequate shear reinforcement
in ties. Some examples of damage to CM buildings in past earthquakes are
shown in Fig. 2.18.