b. Steel - Steel has a high strength-to-weight ratio, and can be 
fabricated into almost any shape. Construction and repair techniques 
are well understood. The only real disadvantage of steel is its ten- 
dency to corrode, requiring increased maintenance or careful engineering 
of corrosion protection features. 
2.3.2 Pier Configuration. Two pier configurations have been stud- 
ied; a standard single deck and a double deck design. Pier length has 
been set at a nominal 1,000 feet. This will accommodate two berths for 
Navy vessels or two berths for cargo carriers. Because of transport- 
ability limitations and requirements for on site towing, the nominal 
module length has been chosen as 330 feet. This means three modules 
would be connected to form a pier. 
Port systems studies (Ref 7) on pier width have concluded that for 
single deck piers the minimum width should be 98 feet and for double 
deck piers 74 feet. Pier elevation for the top deck should be nominally 
13 feet above designed load waterline (DWL) for single deck and 20 feet 
above DWL for double deck. Draft should be less than 26 feet. 
2.3.3 Structural Design. The pier structure can be designed in 
two ways. Either as a rigid structure in which the lateral forces are 
absorbed by batter piles or rigid frame action, or as a flexible struc- 
ture in which the deflections allow the structure to absorb a portion of 
the impact of berthing ships. The four principal structural schemes for 
a floating pier are: 
One long pontoon 
Several large pontoons joined by pivots 
e A series of small pontoons spanned by a number of single span 
decks 
e A series of small pontoons spanned by a continuous deck 
The last two alternatives are the least preferred because of the 
extra deck weight that must be borne by the pontoons. 
D-7 
