PART III 



REVETMENT STABILITY TESTS 



Selection of Test Conditions 



17. Revetment sections were initially subjected to exploratory stabil- 

 ity tests using the abbreviated (4-hr) storm-surge hydrograph (Plate 1). This 

 hydrograph incorporated the most severe breaking waves with periods of 6, 8, 

 10, and 12 sec for each swl of +2.6, +4.3, +6.9, and +8.6 ft msl. Each com- 

 bination of water level and wave period was tested for 15 min; thus, a total 

 storm duration of 4 hr was represented. It was later decided that wave 

 periods of 14 sec and possibly even 16 sec could occur along this reach of 

 shoreline. With this in mind, testing was begun with the intention that once 

 a stable design was achieved for the abbreviated hydrograph, the effects of 

 longer wave periods would be assessed and included in a 13-hr storm-surge 

 hydrograph. Subsequently, it was decided that because of the infrequent oc- 

 currence of l6-sec waves, full revetment stability against their attack was 

 not warranted; therefore, only 14-sec waves were included in the 13-hr hydro- 

 graph (Plate 2). The most severe breaking waves which could experimentally be 

 made to attack the sections for the selected wave period range (6 to 14 sec) 

 were as follows: 



swl 

 ft, msl 



Wave 



Period 



sec 



Most Severe 



Breaking Wave 



Height, ft 



+2.6 



6 





9.0 



+2.6 



8 





11.1 



+2.6 



10 





11.0 



+2.6 



12 





12.6 



+2.6 



14 





12.7 



+4.3 



6 





11.5 



+4.3 



8 





13.1 



+4.3 



10 





12.8 



+4.3 



12 





12.7 



+4.3 



14 





13.1 



swl 

 ft, msl 



Wave 



Period 



sec 



Mos 

 Bres 



He: 



t Severe 

 iking Wave 

 ght, ft 



+6.9 



6 





10.7 



+6.9 



8 





13.4 



+6.9 



10 





15.7 



+6.9 



12 





16.0 



+6.9 



14 





16.3 



+8.6 



6 





12.5 



+8.6 



8 





14.1 



+8.6 



10 





15.8 



+8.6 



12 





16.8 



+8.6 



14 





17.0 



15 



