REPORT DOCUMENTATION PAGE 



Form Approved 

 OMB No. 0704-0188 



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 Office of fulanagement and Budget. Papenwork Reduction Project (0704-0188). Washington. DC 20503. 



1. AGENCY USE ONLY (Leave blank) 



2. REPORT DATE 



July 1999 



3. REPORT TYPE AND DATES COVERED 



Final report 



TITLE AND SUBTITLE 



Damage Progression on Rubble-Mound Breakwaters 



6. AUTHOR(S) 



Jeffrey A. Melby 



5. FUNDING NUMBERS 



7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 



U.S. Army Engineer Waterways Experiment Station 

 3909 Halls Ferry Road, Vicksburg, MS 391 80-6 1 99 



8. PERFORMING ORGANIZATION 

 REPORT NUMBER 



Technical Report CHL-99-17 



9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 



U.S. Army Corps of Engineers 

 Washington, DC 20314-1000 



10. SPONSORING/MONITORING 

 AGENCY REPORT NUMBER 



11. SUPPLEMENTARY NOTES 



Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161. 



12a. DISTRIBUTION/AVAILABILITY STATEMENT 



Approved for public release; distribution is unlimited. 



12b. DISTRIBUTION CODE 



13. ABSTRACT (Maximum 200 words) 



This report addresses depth-limited breaking-wave damage on rubble-mound breakwaters. Few generalized studies have 

 been conducted on this topic; so no engineering methods exist for determining deterioration rates of breakwaters exposed to 

 sequences of storms. A new experiment is discussed measuring incipient motion on both stone and sphere armor layers. An 

 incipient motion criterion is derived for the dominant mode of motion: vertical lift under the steep breaking-wave face. 

 Previous breakwater damage experiments and measurement techniques are thoroughly reviewed. A new experiment is 

 described consisting of seven relatively long-duration breakwater damage test series. The test series were conducted in a 

 flume using irregular waves. Wave height, wave period, water depth, storm duration, storm sequencing, and stone gradation 

 were varied systematically. The experiment yielded relationships for both temporal and spatial damage development. 

 Maximum eroded depth, maximum eroded length, and minimum remaining cover depth are introduced to describe the 

 damaged profile. The mean and standard deviation of these profile parameters are shown to be a function of mean eroded 

 area. An equation is also provided to predict the standard deviation of eroded area as a function of mean damage. Relations 

 for predicting temporal variations of mean eroded area with wave height and period varying with time in steps are shown to 

 describe damage reasonably well. 



14. SUBJECT TERMS 



Armor Hume 



Breakwater Life-cycle costs 



Damage Riprap 



Rubble mound 

 Stability 



15. NUMBER OF PAGES 



216 



16. PRICE CODE 



17. SECURITY CLASSIFICATION 

 OF REPORT 



UNCLASSIHED 



18. SECURITY CLASSIFICATION 

 OF THIS PAGE 



UNCLASSIFIED 



19. SECURITY CLASSIFICATION 

 OF ABSTRACT 



20. LIMITATION OF ABSTRACT 



NSN 7540-01-280-5500 



Standard Form 298 (Rev. 2-89) 



Prescribed by ANSI Sid. Z39-18 

 298-102 



