Civil Engineering Reference
In-Depth Information
FIGURE 4.17
Pancaking of the upper floors of a parking garage
during the Michoacan earthquake in Mexico on September 19,
1985. Note that the restaurant building provided additional lateral
support which enabled the lower three floors of the parking garage
to resist the collapse. (
Photograph from the Steinbrugge Collection,
EERC,
University of California, Berkeley.
)
4.4.3 Shear Walls
Many different types of structural systems can be used to resist the inertia forces in a build-
ing that are induced by the earthquake ground motion. For example, the structural engineer
could use braced frames, moment-resisting frames, and shear walls to resist the lateral
earthquake-induced forces. Shear walls are designed to hold adjacent columns or vertical
support members in place and then transfer the lateral forces to the foundation. The forces
resisted by shear walls are predominately shear forces, although a slender shear wall could
also be subjected to significant bending (Arnold and Reitherman 1982).
Figure 4.18 shows the failure of a shear wall at the West Anchorage High School caused
by the Prince William Sound earthquake in Alaska on March 27, 1964. Although the shear
wall shown in Fig. 4.18 contains four small windows, often a shear wall is designed and
constructed as a solid and continuous wall, without any window or door openings. The X-
shaped cracks between the two lower windows in Fig. 4.18 are 45° diagonal tension cracks,
