ABSTRACT
ABSTRACT: Seismic shaking of large dams constructed with coarse material, such as rockfill, cobbles and gravels, is normally associated with settlements that, depending on both shaking intensity and degree of compaction of the coarse material, can be significant. The observed seismic response of Cogoti and Santa Juana dams, with heights of 83 and 113 m, respectively, is presented. In the case of Cogoti Dam, an accumulated seismic settlement of 1.2 m has been measured, which induced damage in part of the concrete face, without involving any mechanical instability. On the other hand, Aromos Dam, a zoned dam with a height of 42 m, supposed to be founded on liquefiable ground according to SPT data, underwent seismic settlements smaller than 10 cm during the 1985 Chilean earthquake of Magnitude 7.8. The post seismic analysis suggested that liquefaction was actually restricted because the liquefiable soils were confined by rather dense sandy materials.
