Physical Model Study of Breakwater Stability, Kodiak, Alaska: Fid-Bau Portal

Physical Model Study of Breakwater Stability, Kodiak, Alaska

D. L. Ward / W. G. Dubose

This report presents results of a physical model study of the stability of a proposed main breakwater at Kodiak, AK. Model testing was conducted at the U.S Army Engineer Waterways Experiment Station (WES) during the period June to November 1994. A preliminary design and economic study indicated that the cost of breakwater construction could be reduced by $1.2 million by armoring the main breakwater with Core-Loc concrete armor units, recently developed at WES's Coastal Engineering Research Center. Although the Core-Loc armor units have performed well in laboratory tests, Core-Locs had not been tested on a prototype structure and had only minimal testing under three-dimensional conditions of a breakwater head. Testing of the proposed Core-Loc breakwater design was therefore imperative. Test results showed that l,35O-kg (30(X)-Ib) Core-Loc armor units provided stable armoring of the proposed Kodiak breakwater on both the head and trunk when placed in the configuration designated as Plan. 4 in this test series and subjected to the wave environment replicated in these tests. The model was also tested using armor stone with W50 I 450 kg (3.200 lb) Minor scour holes developed on the model during tests with armor stone, but did not threaten the structural integrity of the breakwater. The armor stone was shown to satisfactorily protect the breakwater when subjected to the wave environment replicated in these tests.