The Earthquake Engineering Online Archive

Influence of local soil conditions on building damage potential during earthquakes

Seed, H. Bolton; Idriss, I. M.

UCB/EERC-69/15, Earthquake Engineering Research Center, University of California, Berkeley, 1969-12, 43 pages (450/S41/1969)

Records of ground motion in recent earthquakes have shown that even in localized areas, variations in soil conditions can have a major influence on damage patterns and on both the amplitude and frequency characteristics of the ground surface motions. This report covers the following topics: lateral forces on buildings and their effects; evaluation of effects of soil conditions on damage potential; influence of earthquake magnitude and epicentral distance on damage potential; and use of analytical procedures for assessing potential damage distribution in relation to soil conditions for great distant earthquakes and for very strong nearby earthquakes. To illustrate the potential of the method described in the report for assessing damage potentials in local areas, examples are discussed for buildings of various types and heights in San Francisco that are founded on different types of soils and subjected to earthquake magnitudes of various sizes. In particular, examples are discussed for the 1957 San Francisco earthquake and for a hypothetical earthquake of magnitude 8.25 occurring about 80 miles away and for an earthquake of magnitude 7.5 occurring along a fault about 20 miles from the city.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-69-15.pdf (5 MB)