Abstract :
Structural damage due to permanent ground displacement is a common occurrence during seismic events. Light-frame structures, typical of residential construction, seem both particularly susceptible to and easily reinforced against moderate ground failure. Because the foundations of these structures typically receive little or no engineering attention, a spreadsheet capable of quickly checking the capacity of a foundation to resist anticipated lateral and vertical displacement might encourage residential designers to require more appropriate foundation cross sections. Unfortunately, a simple strengthening of the foundation elements is generally insufficient. Designs must also eliminate noncontinuous interior bearing supports, which are highly vulnerable to horizontal ground displacement. Site remediation, including the installation of free-draining base materials, may also be needed to enable placement of the footer at or near grade. Finally, we should strive for more efficient designs: smaller, more compact structures, with more redundant, lightly loaded foundation elements.
