Strong motion data at embankment dams: collection, analysis and engineering implications

A database analysis of seismic records on earth dams available in the literature is presented, with the aim to verify and update the existing relationships among some seismic motion parameters and the dam response. The cases were selected in order to have both crest acceleration and base acceleration recorded on the rock outcrop. The recorded peak accelerations and the amplification ratios are elaborated in order to recognize a general trend in the database as a whole. The factors that were considered to affect the dam responses are the type of dam, the dam height, the narrowness of the valley. Elaborations for singular acceleration component were also conducted. The results show that a significant effect of the non-linearity of the mechanical behavior is active in decreasing the motion amplification. Despite this, rock-fill dams seems to distinct from the others having a quite high amplification also at high seismic levels. The transversal component is mainly influenced by the amplification that decreases as the length of the dam increases. The results could be of practical use from the engineering perspective, representing a framework respect to which the outcomes of the seismic numerical analysis can be compared and verified.