Figure 5b. Multiple-tined rock 

 foundation concept 



Figure 5a. Three-tined rock 



foundation concept 



Figure 5c. Adjustable three-tined rock 

 foundation concept 

 (adapted from Reference 22) 



OctJll of "plasEic-hingc," 

 csploylng friction betvocn 

 leaves of hinge to develop 

 limiting nonent. Alternate 



Figure 5d. Six legged "plastic-hinge" rock foundation concept 

 13 



