Table 6-2. Model and prototype breakwater material. 



Breakwater material 



Weight of tribar and stone 



Model 



(lb) 



Prototype 



(lb) 



(ton) 



W (tribar) 

 W (stone) 

 W/2 (stone)' 

 W/3 (stone) 

 W/10 (stone) 

 W/2 (stone)2 

 Core stone 



0.30 

 0.47 to 0.75 

 0.23 to 0.46 

 0.14 to 0.46 

 0.04 to 0.07 

 0.02 to 0.04 

 12 X 10-^ to 21 X 10-" 



1,500 to 3,000 



1,000 to 1,500 



5 to 90 



5 



10 to 16 



5 to 10 



3 to 10 



' Used under the limestone armor units. 

 ^ Used under the tribar armor units. 



Table 6-3 gives the gradations o£ the limestone blocks used in the 

 model tests for the armor units and underlayers, based on estimates of 

 the available stockpiled units for the prototype structure. 



Table 6-3. Prototype stone gr< 



idation. 



Type of stone 



Prototype weight 

 (ton) 



Pet. by weight 



W 



10 



30 





12 



30 





14 



30 





16 



10 



W/2 



5 



33 





8 



33 





10 



34 



W/3 



3 



25 





5 



25 





8 



25 





10 



25 



8 Test Procedures. The stability of each breakwater 

 test section was determined by constructing the section in the wave flume 

 and subjecting it to the attack of test waves, varying in period from 7 

 to 11 seconds and in height from 5 to 20 feet (prototype dimensions), 

 for durations varying from a few minutes to about 6 hours prototype time. 

 Tests were made using Stillwater levels of +4.0 and 0.0 feet LWD, corre- 

 sponding to water depths at the lakeside toe of the structure of 47 and 

 43 feet, respectively. The behavior of the test section and the extent 

 of damage were determined by visual observation. Design waves for the 



376 



