Page 214 - Advanced Design Examples of Seismic Retrofit of Structures

Example of a Steel Frame Building With Masonry Infill Walls Chapter 4 207

(A) (B)
FIG. 4.7 Some lesser studied effects on the behavior of infill walls. (A) Interaction with concentric
braces; after Bam earthquake, 2003 (Permission from DRES). (B) Weak line from the duct of the
heater; after Ahar earthquake, 2012. (Photo taken by Mohammad Yekrangnia.)

(A) (B) (C)
FIG. 4.8 Failure modes of infill walls. (A) Separation of infill and frame; after Ahar earthquake,
2012. (B) Shear-sliding failure; after Ezgeleh earthquake, 2017. (C) Corner-crushing failure; after
Ezgeleh earthquake, 2017. (Photos taken by Mohammad Yekrangnia.)

The infill walls can also experience failure in out-of-plane direction. Perfor-
mance of the infill walls in out-of-plane direction significantly depends on the
extent of arching action activated in the infill wall. This action is related to the
infill wall’s area, the ratio of height to thickness of infill, rigidity of the frame
members, and openings. Examples of out-of-plane failure of infill walls are
shown in Fig. 4.9.
In conclusion, the effects of infill walls on the seismic performance of frame
buildings are prominent and should be taken into account in design and
evaluation.