WHARF 



'ANODE HEADER CABLE 



RECTIFIER 



TO A NOOK 



RECTIFIER- 



TO 3TNUCTUM 



v 



* 



HIGH 



WATER LINE 







LOW 



WATER LINE 







^SHEET STEEL 

 PILE BULKHEAD 











WHARF 



WHARF 



WHARF 





PILE 



1 



PILE 



-DURJCHLOR 51 

 ' TYPE E ANODE 



PILE 



^^ 





CHANNEL 

 BOTTOM 





«*sr 



*W 













Figure 104. Cross section of wharf used in example. 



(1) Conditions . The steel sheet-pile bulkhead is 300 meters (980 

 feet) in length. There are approximately 9 meters (30 feet) of water- 

 exposed steel or 2 700 square meters (29 000 square feet) including a two- 

 foot splash zone and about 3 000 square meters (32 300 square feet) embedded 

 in the sandy clay soil. The steel surface contacting the water is expected 

 to require about 55 milliamperes per square meter (5.1 milliamperes per 

 square foot) for protection. The embedded part, 3 000 square meters is 

 expected to require about 22 milliampere per square meter (2.0 milliamperes 

 per square foot) for protection. 



(2) Calculations . Current requirement: 



2 700 square meters @ 55 milliamps per square meter = 149 amperes. 



3 000 square meters @ 22 milliamps per square meter = 66 amperes. 



Total current required = 215 amperes. 



(3) Resistance . Anodes used will be Durichlor 51 Type E, 7.6 

 centimeters (3 inches) in diameter, 1.5 meters (60 inches) long, to be 

 suspended in the water under the wharf using polypropylene rope. These 

 anodes are rated at 4 amperes per anode for long service life. 



215 (amperes required) 

 4 (amperes per anode) 



54 anodes 



369 



