Table 25 (Concluded) 



Date(s) Construction and Rehabilitation History 



1968- Visual examinations and detailed surveys showed the sheet-pile 

 1969 cylinders and walls to be in need of immediate repairs. Voids be- 

 tween the original concrete caps and the underlying sand existed in 

 virtually all cylinders not repaired in 1963. Corrosion was the 

 main cause of deterioration, with subsequent removal of sand from 

 the cylinders because of wave and current action. Rehabilitation of 

 the jetties was carried out In 1969 (Figure 40). The sheet-pile 

 walls and cylinders (except the outer two on the north and outer one 

 on the south) were removed down to +2 ft mlw, and the sand within 

 the cylinders were removed to mlw. The existing concrete cap 

 (broken into pieces less than 12 in. long) and I- to 12-in. bedding 

 stone were placed in the cylinders to +2 ft mlw. This was overlayed 

 with 4- to 10-ton capstone (70 percent > 8 tons) , with similar cap- 

 stone placed along the connecting walls, to bring the structure to 

 the original design elevation of +6 ft mlw with a crown width of 

 10 ft. Additional 4- to lO-ton capstone was placed, as needed, to 

 bring the side slopes up to IV: 2H. On the outer 50 ft of the 

 jetties, the side slopes were 1V:3H. Finally, asphaltic concrete 

 was placed (Figure 40) on the jetties. This material was placed 

 over the entire crown width down to mlw, and had IV: IH side slopes. 

 The design of the jetties used Hudson's formula with wave heights of 

 12 to 16 ft and wave periods of 7 to 9 sec. 



1978 Repair to jetties consisted of resetting stone and adding 6- to 

 12-ton stone (75 percent > 10 ton) on the outer 200 ft of the 

 jetties and 2- to 6-ton stone on the next 450 ft of the jetties as 

 needed to solidify the structure. 



1985 The jetties are in good condition except for their head sections 

 which are in need of some repair. 



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