Table 3 (Continued) 



Date(s) Construction and Rehabilitation History 



1958 A storm (Figure 8) with estimated breaking wave heights at the 

 structure of 25 ft caused severe damage to seaward ends of both 

 breakwaters. The east breakwater was breached for a length of 

 154 ft in the original armor stone-tetrapod transition area, and 

 at least six tetrapods were displaced from the head. On the west 

 breakwater all the tetrapods (approximately 60 units) from the 

 harbor-side quadrant of the head were swept away. The west 

 breakwater's 1-V:2-H harbor-side slope appeared to be a major 

 design deficiency. 



1959 Stopgap repairs of damage from the November 1958 storm were 

 completed, and design analysis for a major rehabilitation was 

 initiated. These repairs consisted of construction of a heavy 

 monolithic concrete cap (east breakwater, $275,000) and placement 

 of the heaviest available armor stone (12-ton minimum) on the 

 seaward slope. 



1965 During 2-3 February, 1 month after awarding the tribar-placing 

 contract, a storm with hindcasted deepwater wave heights of 27 ft 

 and period of 17 sec caused damage to the heads of both 

 breakwaters. 



1966 Major rehabilitation (Figures 5 and 9(a,b) consisted of repair of 

 both breakwater heads and the first 355 ft shoreward of the east 

 breakwater head. On the inboard quadrants of the breakwater 

 heads, two layers of 35- ton tribars were placed over the lower 

 third of the side slope, and two layers of 50-ton tribars were 

 placed over the upper two-thirds. Two layers of 35-ton tribars 

 were placed on the sea-side slope of the east breakwater head and 

 buttressed against the concrete rib cap constructed on the crest; 

 827 and 181 35-ton reinforced tribars were placed on the east and 

 west breakwaters, respectively; and 43 and 173 50-ton reinforced 

 tribars were placed on the east and west breakwaters, respec- 

 tively. Except for the concrete rib cap, all repair work was 

 model tested (Jackson 1964). The total cost of repair work was 

 $1,560,000. 



1967 In December a storm from the north caused severe damage to the 

 west breakwater trunk, dislodging the 8-ton armor stone and under- 

 mining the core material. Concrete grout which previously had 

 been applied to the crest contributed to the failure by causing 

 excessive back pressure which resulted in more rapid erosion of 

 the core and did not permit the capstones to settle until large 

 voids had developed underneath and large cap sections had failed. 



(Continued) 



(Sheet 3 of 5) 



19 



