Gajan and Kutter 2008
The authors explained capacity, settlement and energy dissipation of shallow footings subjected to rocking. They showed that the combination of rocking footings with structural base isolation and energy dissipation devices improve the performance of the structure during seismic loading.
System Concept
The shearing of soil under the footing dissipates energy through friction, and due to uplift related with rocking, shallow footings have significant self-centering characteristics. For load transformation of a frame-shear wall structure supported by shallow foundations, lateral loads during seismic loading are transferred from beams to shear wall to shallow foundation.
Experimental Study, Results, and Discussion
Several series of centrifuge experiments were performed. Each of the tests consists of several shear wall-shallow footing models tested under slow lateral cyclic and dynamic loading conditions. Different types of foundations and loadings were used in the experiments. Slow lateral cyclic loading by an actuator and dynamic base shake were used for shallow foundations.
The results from the tests showed that a rocking footing has a very ductile behavior with negligible loss of capacity, significant energy dissipation capacity, and it also includes self-centering mechanism associated with uplift and gap closure upon unloading.
Reference
Gajan, S. and Kutter, B. L. (2008). "Capacity, Settlement, and Energy Dissipation of Shallow Footings Subjected to Rocking," Journal of Geotechnical & Geoenvironmental Engineering, 134.8, pp. 1129-1141.