Seismic study of a typical radial floodgate in a UK gravity dam

A seismic evaluation of a typical UK radial gate design, based on the arran gement at Kilmorack Dam, was conducted for Scottish and Southern Energy. It s purpose was to assess the general seismic risk to radial gates in the Uh, and to evaluate appropriate methods for their seismic analysis. The study included dynamic hammer tests on the gate, the seismic analysis of a three- dimensional finite element model, and the equivalent-static analysis of sim ple two-dimensional models. Natural frequencies and mode shapes from the te sts correlated reasonably with the three-dimensional model, validating it f or seismic analysis. A response analysis was run for the three-dimensional model using artificial accelerograms generated from a standard UK earthquak e response spectrum, The demand on the gate for the seismic condition was a lmost double the hydrostatic demand, indicating that this and other similar non-seismically designed gates may be vulnerable to earthquakes. Generally , the equivalent-static analysis yielded higher responses than the dynamic three-dimensional analysis, but the two-dimensional models could not repres ent important three-dimensional effects in the gate. This study showed that the equivalent-static analysis of simple models is appropriate for prelimi nary seismic assessments of radial gates, while dynamic analyses of three-d imensional models should be employed for detailed analyses.