Constructibility Issues 



Types of construction 



Constructibility of a breakwater project can play a major role in the overall 

 feasibility of the project, and design should thoroughly consider the methods, 

 means, and materials of construction at a specific site. Construction costs for 

 breakwaters depend on a number of factors including access to the 

 construction site, water depth at the structure location, design crest height, 

 width of the breakwater, side slopes, and foundation preparation (Fulford 

 1985). 



Typically, large-scale detached breakwater projects, such as the 55 

 segments recently constructed at Presque Isle, require water-based 

 construction using floating equipment such as a barge and barge-mounted 

 crane (Figure 60). Construction limitations may determine the distance 

 offshore where the breakwaters will be located. Dally and Pope (1986) 

 describe a "zone" where construction may be impractical without highly 

 specialized equipment. The landward boundary of the zone is the maximum 

 depth at which land-based equipment can operate (they suggest 1 to 1 .5 m), 

 and the seaward boundary is defined by the draft of floating construction 

 vessels (they suggest 2 to 3 m), although wave climate and tidal range can 

 affect the limits of this zone. More information on construction considerations 

 can be found in Maquet (1984), Bruun (1985), and EM 1110-2-2904. 



Figure 60. Breakwater 22 under construction at Presque Isle, Pennsylvania 



Chapter 5 Other Design Issues 



107 



