CONCRETE ARMOR UNITS 



Concrete Armor Units 



Rock Filter 



SECTION 



Tribar revetment tested at CERC. 



Prototype Installation : 



Concrete armor units such as tribars, tetrapods, quadripods , and 

 dolosse have been used on many rubble-mound coastal structures. 

 Examples are given by Hudson, 1974. 



Wave Tank Tests : 



Wave tank tests of several concrete armor shapes have been conducted 

 at the U.S. Army Engineer Waterways Experiment Station (WES), CERC, 

 and other laboratories. Some of these test results are referenced 

 by Hudson, 1974. 



Design Factors : 



Zero-damage wave height: Depends on weight of unit and interlocking 



characteristics . 



Wave runup: 0.5 to 0.8 compared to smooth slope. 



Wave reflection: Low. 



Remarks : 



Different types of concrete armor units exhibit stability against wave 

 attack two to six times greater than equal weight rock armor. 

 Concrete armor units are usually not cost effective where suitable-size 

 rock is locally available. 



These armor units can be used to revet the surface of a rock breakwater 

 or an embankment. 



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