except the area of coverage was increased. The waves tended to break on the 

 structure and then rush out the dogleg, and it was hoped additional units in 

 this area would dissipate enough of the wave energy to protect the toe units 

 in the seaward transition area of the elbow. A total of 406 42-ton rehabili- 

 tation dolosse were used. Damage of the seaward transition was still unac- 

 ceptable. Photos 126-128 show the structure after testing. 



47. Plan 17 (Plate 19 and Photos 129-131) was similar to Plan 15, ex- 

 cept the area of coverage again was increased. A total of 443 42-ton reha- 

 bilitation dolosse were placed. This plan performed satisfactorily for the 

 abbreviated hydrograph. Photos 132-134 show the structure after testing. 



48. Plan 18 (Plate 20 and Photos 135-137) was a refinement of Plan 17. 

 The total number of 42-ton rehabilitation dolose was reduced to 398 by remov- 

 ing units near the crown of the dogleg. Plan 18 performed satisfactorily for 

 the abbreviated hydrograph; results are shown in Photos 138-140. The test 

 section was rebuilt and again subjected to the abbreviated hydrograph. A 

 total of 394 rehabilitation units were used and Photos 141-143 show the struc- 

 ture after the repeat test. The repeat test sustained more damage than the 

 original, but the amount of movement was considered acceptable. Plan 18 was 

 rebuilt and subjected to a full-length storm (Hydrograph A, Table 2). A total 

 of 410 rehabilitation dolosse were placed. Plan 18 performed satisfactorily 

 for the full-length storm. Photos 144-146 show the structure after testing. 

 Concern arose as to the prototype constructability of the toe trench; there- 

 fore, it was decided to develop alternative plans. 



49. Plan 19 (Plate 21 and Photos 147-149) was similar to Plan 18, 

 except a rock buttress was placed around the outer perimeter of the seaward 

 transition. Also three concrete blocks were added to represent remnants of 

 the deteriorated cap of the old breakwater extension. Mo trenching was used 

 for this plan, and special placement was used for the dolos toe units. The 

 rock buttress was placed before the rehabilitation dolosse and consisted of 

 25-ton armor stone two layers deep and approximately 35 ft wide. The total 

 number of armor stones added was 188; assuming a specific weight of 170 pcf 

 and a porosity factor of 0.63, the total weight of stone used was 4,700 tons 

 with a volume of approximately 3,250 cu yd. A total of 408 42-ton rehabilita- 

 tion dolosse were used. Plan 19 was subjected to the abbreviated hydrograph. 

 The rock buttress sloughed off in the lower region of the seaward transition 

 and was undamaged near the crown of the dogleg where the stone was protected 



19 



