Shear Walls in the Field
|A Downtown Store
|Although the front of the building does have a wall
section, the change
in the facade suggests it is nothing more than a combination of two
|A Shoppe Most Curious
|I see one wall between the door and the shop on the
left. Is this
enough to resist the lateral load at the front wall line?
|Those Pesky Shear Walls
|The trouble with shear walls is they get in the way of the displays.
The Three-Sided Box
It is possible to construct a shear wall building using only three walls. You've seen them used as garages. And you've seen an example of them used as downtown stores. The following diagram is helpful in understanding how this type of building works:
|Schematic of a Three-Sided Building
|If the force is applied at the right, the only matching
resistance available in
a parallel direction is the rear wall. The offset between the applied and
resisting forces causes a clockwise rotation. As we have seen before,
forces must be added to counteract the rotation leading to shear in the
side walls. The deflected shape of the structure is shown for reference.
One way to judge whether a design is worthwhile is to see how it performs in the field. Let's travel to Fortuna, California after the Eureka earthquake in the early part of this decade to see how three-sided buildings performed.