Summary of Results for the Concrete Block 

 Plans 



As evidenced in tests of Plans 4 and 4R, stability of the original 2.5-ft 

 by 5.5-ft by 6-ft concrete blocks is only marginally acceptable for the -8.6-ft 

 erosion depth. However, tests of Plans 5 and 5R show the blocks to be 

 acceptable for the 3.6-ft erosion depth. The 3-ft by 5.25-ft by 5.25-ft modified 

 concrete blocks (Plans 6 and 6R) are completely stable for the -8.6-ft erosion 

 depth and can be assumed stable for any lesser depth. Tests at the -10-ft ero- 

 sion depth (Plans 7-9R), show the 2.5-ft by 5.75-ft by 5.75-ft block design 

 (Figure 12) to be hydraulically stable; however, a gap may develop between 

 the slope and crest blocks as a result of toe slippage and subsequent downslope 

 slippage of the slope blocks. 



The 200- to 2,000-lb toe and crest stone used on Plans 4, 4R, 5, 5R, 6, and 

 6R showed significantly improved stability relative to the 200- to 1,000-lb 

 stone used on the stone armor plans. Based on an estimate of the material 

 volumes in the as-built model sections and the number of stones moved during 

 wave attack, displacement of 1 to 2 percent of the toe stone and 2 to 4 percent 

 of the crest stone can be expected during wave attack at the +4- and +7-ft 

 swl's. 



Initial tests at the -10-ft erosion depth (Plans 7 and 7R) showed the 200- to 

 2,000-lb stone to be marginal for the toe of the structure. Therefore, this 

 weight was increased to 200 to 4,000 lb for Plans 8-9R. 



Wave Overtopping Tests 



Limited wave overtopping tests were conducted on Plan 8. To obtain 

 model overtopping rates, calibrated containers were placed behind and above 

 the model revetment to collect water overtopping the structure (water was 

 transferred by pump to the overhead container). Water surface elevations in 

 the overtopping containers were measured with a point gauge before and after 

 each test to determine the total quantity of overtopping. Photo 53 shows a 

 general view of the model setup. Overtopping tests were conducted at swl's of 

 +2.5 and +4.0 ft mlt for the following wave conditions: 



Chapter 3 Tests and Results 



