3) Earthquake Loading (Refer to Wilson, 1969) 



- Cohesive soils not susceptible to significant 

 strength loss during earthquake loading. 



- Granular soils can liquefy during earthquake 

 loading. 



- Granular liquefaction is a function of soil rela- 

 tive density. Potential for liquefaction is 

 illustrated below. 



Liquefaction potential profiles for 

 earthquake loading of granular soils 

 (from Seed and Idriss, 1971). 



Maximum ground accelerations are a 



function of earthquake magnitude 



and distance from the quake epicenter. 



Maximum acceleration associated 

 with earthquakes of various 

 magnitudes (from Seed at al., 1969). 



If analysis of the site and its expected earthquake indicates a high 

 probability of soil liquefaction, the site is hazardous. Use of plate 

 anchors which are loaded a significant percentage of time should be 

 avoided. 



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