PART III: TESTS AND RESULTS 

 Test Facilities and Equipment 



24. All tests were conducted in an L-shaped wave basin which is 250 ft 

 long, 50 and 80 ft wide at the top and bottom of the L, respectively, and 

 4.5 ft deep (Figure 2). The test facility was equipped with a flap-type gen- 

 erator which is capable of producing monochromatic waves of various periods 

 and heights. 



Calibration of Test Facility 



25. Normal procedure at the US Army Engineer Waterways Experiment Sta- 

 tion (WES) is to calibrate the wave facility without the breakwater structure 

 present. This is the most accurate means of calibrating, and is analogous to 

 the prototype conditions for which the measured and/or hindcast wave data were 

 determined. Electrical resistance-type wave gages were positioned in the wave 

 flume at a point that would coincide with the toe of the proposed breakwater 

 section, and the wave generator was calibrated for various selected wave 

 conditions. 



Test Procedure 



26. A typical stability test consisted of subjecting the test section 

 to a series of waves from a previously determined hydrograph. The test sec- 

 tion was subjected to wave attack in approximately 45-sec intervals, between 

 which the wave generator was stopped and the waves were allowed to decay to 

 zero height. This procedure was necessary to prevent the structure from being 

 subjected to an undefined wave system created by reflections from the break- 

 water and wave generator. Newly built test sections were subjected to a short 

 duration (five or six 45-sec intervals) of shakedown by using a wave equal in 

 height to about one-half of the estimated no-damage wave. This procedure pro- 

 vided a means of allowing consolidation and armor unit seating that would nor- 

 mally occur during prototype construction. 



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