Method of constructing test sections 



10. The typical existing east breakwater cross section supplied by NCB 

 (Plate 1) was constructed to reproduce as closely as possible the existing 

 breakwater construction. Core material was dumped by bucket or shovel, 

 smoothed to grade, and compacted with hand trowels to simulate consolidation 

 that has occurred due to wave action. The core was covered with one layer of 

 specially shaped laid-up stone. Armor stones were placed one at a time in an 

 effort to obtain the existing keyed-and-fitted construction. The bedding, 

 berm, and underlayer rehabilitation materials, designated by NCB for their 

 respective existing or proposed rehabilitation designs, were sequentially 

 placed and smoothed to grade on the lakeside of the existing breakwater 

 section in a manner that reproduced usual construction methods. The lakeside 

 slope then was covered with two layers of randomly placed dolosse or armor 

 stone, depending on the plan being tested. 



Model operation 



11. After "before-test" photographs were taken, the flume was flooded 

 to an appropriate depth and the structure was exposed to shakedown and test 

 wave conditions. Shakedown waves allowed some natural settling and nesting of 

 the newly constructed section that would occur under lower level wave condi- 

 tions prior to being exposed to a design level storm. Prototype test time was 

 accumulated in 30-sec (model time) cycles, i.e., the wave generator was 

 started, run 30 sec, and then stopped. This procedure prevented contamination 

 of incident waves by waves rereflected from the wave generator. After each 

 30-sec cycle, sufficient time was provided for the flume to still out before 

 the next cycle was run. During stilling time between cycles, detailed model 

 observations of the structure's response to the previous cycle of test waves 

 were recorded by the model operator. Observations included any movement 

 occurring on the structure and a general statement of the structure's condi- 

 tion at that point in the test. All test conditions were run for at least the 

 durations indicated for each hydrograph step. Where damage did not stabilize 

 during the normal duration of the hydrograph step, the test condition duration 

 was extended until damage had stabilized or the damage level exceeded an 

 acceptable amount. At conclusion of the hydrograph, the flume was drained and 

 the after-test condition of the structure was summarized in test notes and 

 documented with photographs. Where test hydrographs were run back-to-back, 

 the flume was refilled with water and the structure was exposed to conditions 



