3 Tests and Results 



Method of Constructing Test Sections 



All experimental revetment sections were constructed to reproduce as 

 closely as possible results of the usual methods of constructing full-scale revet- 

 ments. Underlayer stone was added by shovel and smoothed to grade by hand 

 or with trowels. Armor units used in the cover layer were specially placed 

 with their least dimension (2.5 ft) perpendicular to the underlayer. After each 

 test, the armor units were removed from the breakwater, all of the underlayer 

 stones were replaced to the grade of the original test section, and the armor 

 was replaced. 



Selection of Test Conditions 



Based on siting of the breakwater in shallow water, tests were conducted 

 with a TMA spectrum using peak periods (T ) of 8 and 10 sec. The wave 

 basin was calibrated for still-water levels (swl's) of +4, +7, +9.5, and +14 ft 

 mean low tide (mit) for assumed erosion depths of -3.6 and -8.6 ft mit 

 (Figure 3). Thus, as summarized below, eight testing depths were considered. 



Prior to testing of the final plans, it was 

 decided that an erosion depth of 

 -10.0 ft mit was plausible. Using this 

 new assumption and adding a +11.5-ft 

 swl yielded the following five depths: 



Erosion 

 Depth, 

 ft, mit 



swl, 

 ft, mit 



Total 

 Depth 

 at Toe, ft 



-3.6 



+4.0 



7.6 



-3.6 



+7.0 



10.6 



-3.6 



+9.5 



13.1 



-3.6 



+ 14.0 



17.6 



-8.6 



+4.0 



12.6 



-8.6 



+7.0 



15.6 



-8.6 



+9.5 



18.1 



-8.6 



+14.0 



22.6 



Erosion 

 Depth, 

 ft, mit 



swl, 

 ft, mit 



Total Depth 

 at Toe, ft 



-10.0 



+4.0 



14.0 



-10.0 



+7.0 



17.0 



-10.0 



+9.5 



19.5 



-10.0 



+ 11.5 



21.5 



-10.0 



+14.0 



24.0 



Chapter 3 Tests and Results 



