Section II. STEEL PILING 



1. General 



Steel sheet, H bearing, and cylindrical piles are made in a 

 variety of sizes, and are used in marine structures such as piers, bulk- 

 heads, jetties, groins, dolphins, and offshore drilling platforms. Piles 

 for these structures are rolled from several types of steel such as ordi- 

 nary carbon steel, high strength steel, and steel with both high strength 

 and improved corrosion resistance. 



2. Ordinary Carbon Steels 



Carbon steels with American Society for Testing Materials (ASTM) 

 (1959) designations A-328, A-252-55, A-36 and A-T are among those used to 

 produce steel piling. The minimum yield points of these steels range from 

 30,000 to 38,500 pounds per square inch. These carbon steels give good 

 service in unpolluted fresh water, but may deteriorate rapidly when ex- 

 posed to splashing seawater or abrasive bottom materials in motion in 

 seawater. 



3. High strength and Corrosion Resistant Steels 



Several high-strength steels are now rolled into piling. Steels 

 with ASTM designations A-UUO, A-i;Ul, and A-2i+2 are in this category. In 

 addition to these high-strength steels, another group of steels have been 

 developed which contain columbium or vanadium. These steels have yield 

 points ranging from approximately U5,000 to 55,000 pounds per square inch 

 (Lindahl, 196^^). Although these steels have higher strength, reports do 

 not indicate any improvement in corrosion resistance. A high-strength 

 low-alloy steel, which is often referred to as corrosion resistant steel, 

 contains higher percentages of copper, nickel, silica and phosphorus than 

 A-328 steel and is reported to be superior to, the A-328 steel in resisting 

 corrosion in the splash zone. It was concluded from tests at Harbor 

 Island, North Carolina, that the corrosion resistance of this steel in 

 the splash zone is three times that of A-328 steel where mild wave action 

 exists and twice that of A-328 steel where considerable wave action 

 exists (U. S. Steel, 196i|). 



Section III. SEAWATER 



1. General 



Seawater contains most of the known chemical elements, but it 

 is basically a solution of salts dissolved in water. This salt water is 

 the home of many types of plant and animal life. This section describes 

 some of the more important characteristics of seawater which influence 

 the corlrosion of steel piling installed therein. 



2. Salinity and Chlorinity 



The salt content of seawater is usually expressed as 

 salinity or chlorinity. Chlorinity is defined in Sverdrup, Johnson, 



