Design Philosophy in Regions of Low-to-Moderate Seismicity
By Dominic Kelly of Simpson Gumpertz & Heger Inc.
The design philosophy in regions of low-to-moderate seismicity is and should be different than
the philosophy in regions of high seismicity. Differences in intensity of ground shaking, the
amount of drift buildings undergo, and the inherent lateral strength of the gravity systems
justifies these differences. But, the design philosophy in regions of low-to-moderate seismicity
is not as well developed as it is in regions of high seismicity. This results in greater
inconsistencies in the level of life-safety and property damage protection that various building
types provide in low-to-moderate regions.
Mr. Kelly will discuss why a different design philosophy is justified in regions of low-to-moderate
seismicity and why the current design and construction practices will likely lead to greater
inconsistency in building response to a seismic event. He will focus on differences in intensity
of ground shaking for earthquakes of varying return periods, differences in the amount of
building drift expected, and differences in the structural configurations and details that designers
specify in regions of low-to-moderate seismicity versus regions of high seismicity.