by dolosse. However, the armor stone of the barricade in the central region 

 of the seaward transition (in the range of swls used for testing) where the 

 wave energy was most severe were completely washed out. The rock buttress 

 did afford the dolosse some protection but the performance of this plan was 

 considered marginal. Although only one dolos was actually displaced, there 

 was a separation of dolosse near the seaward transition toe. These units 

 probably would have been displaced during a longer storm. Photos 150-153 

 show the structure after testing. 



50. Plan 20 (Plate 22 and Photos 154-156) had about the same area of 

 coverage as Plan 18; however, 74 rehabilitation dolosse were removed and re- 

 placed with 82 37-ton tetrapods (37-ton tetrapods were used since this was 

 the model size tetrapod available nearest to the 42-ton dolos size). The tet- 

 rapods were placed in one layer. It was thought that the tetrapods might be 



a more appropriate shape for interfacing the existing stone. A total of 334 

 42-ton dolosse were used. The tetrapods suffered extensive damage. There was 

 minimum movement of the dolosse during the abbreviated hydrograph, but since 

 they had lost the protection afforded by the tetrapods it is likely damage 

 would have progressed to this area for a longer duration storm. Photos 157- 

 159 show the structure after testing. 



51. Plan 21 (Plate 23 and Photos 160-162) was similar to Plan 20, ex- 

 cept more dolosse were replaced with tetrapods and the tetrapods were placed 

 in two layers. A total of 304 42-ton rehabilitation dolosse and 116 37-ton 

 tetrapods were used. The tetrapods sustained severe damage; damage progressed 

 to the dolosse. Photos 163-165 show the structure after testing. Using tet- 

 rapods to stabilize the seaward transition was found to be unfeasible. 



52. Plan 22 (Plate 24 and Photos 166-168) was similar to Plan 18, 

 except that dolos toe units extended along a line which intersected with one 

 of the concrete block remnants from the earlier breakwater extension. It 

 was hoped the concrete block would act as a buttress for the dolosse. Wo 

 trenching or other buttressing was used. The toe units of the rehabilita- 

 tion dolosse were specially placed. A total of 445 42-ton rehabilitation 

 dolosse were used. Although only four dolosse were displaced while testing 

 with the abbreviated hydrograph, performance of the plan was considered mar- 

 ginal. There was a separation of toe units along the lower section of the 

 seaward transition; these units probably would have been displaced for a 

 longer duration storm. The concrete block did provide some protection to 



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