Dynamic Interaction between Pile Group and Non-linear Soil

Soil behavior had a significant effect during this earthquake on structural behavior and surface features in several areas of Northern California. Large ground movements with lateral sliding due to soil liquefaction have occurred in Moss Landing, the levees at Santa Cruz, Marina area of San Francisco, Oakland Airport, Oakland-side Bay Bridge approaches and in other areas of San Francisco Bay. Peak accelerations monitored at various locations are shown in Table 1 and Fig. 2(a) (USGS, 1989). Although the extent of the damage due to soil liquefaction may be related to the magnitude of the acceleration developed at each of the sites, evidently other factors play a part in the soils' response. The contribution of soils to the collapse of a portion of the Nimitz Freeway has not been ascertained. Many structures in the Bay Area are built on piles, and useful information
on the response of such soil-pile-structure systems during the earthquake will be obtained. In order to apply the observations of pile response, liquefaction, and deformation behavior to sites which will liquefy in future earthquakes, it is desirable to develop and verify analysis procedures.