Figure 37. Hermosa Beach recreation pier. 



These piles may vary in cross section from 0.15-meter [6 inch) diameter 

 round piles to 0.76-meter (30 inch) solid square or octagonal piles and 

 1.2 mete: (4 foot) round hollow piles. Hollow piles usually have a 0.15- to 

 0.30 meter wall. The restrictions on concrete pile size are determined by 

 the equipment required to manufacture them, e.g. the pile bed, forms and, 

 if required, prestressing equipment as well as the pile handling equipment 

 such as cranes, barges and piledriver. 



(3) Submerged Structures. Concrete is an ideal material for the 

 construction of submerged structures. It may be used for monolithic 

 submerged structures such as structural elements of bridges or precast- 

 prestressed for pipelines, intake and outfall structures, and bridge 

 piers. Other submerged structures usually built of concrete include tunnels 

 for vehicular and railroad traffic and utilities. 



(4) Floating Structures. Many concrete pontoons of various 

 shapes and size have been constructed as parts of pontoon bridges, quays, 

 wharves, and floating facilities for small boats and seaplanes. Floating 

 breakwaters of precast reinforced concrete pontoons have been installed in 

 Tenakee Springs, Sitka, and Ketchikan, Alaska, and Blaine, Everett, and 

 Port Orchard, Washington. Other structures such as skiffs, launches, 

 scows, barges, floating drydocks, and permanent offshore structures have 

 been constructed of concrete. The construction of fixed breakwaters by 

 floating precast units into place is not uncommon. Caisson units are 

 constructed on a land site, floated into position, sometimes thousands of 

 miles from the construction site, then submerged on the ocean bottom and 

 filled with sand or dredge material. Most any type of floating or sub- 

 mersible structures, at one time or another has been built of concrete. 



164 



