coincide with the toe of the proposed revetment section, and the wave gen- 

 erator was calibrated for various wave conditions. Once calibration was com- 

 pleted, the vertical seawall and first revetment section were placed in the 

 wave flume and the wave generator was "tuned" to determine the most severe 

 breaking waves that could be experimentally made to attack the structure; 

 i.e., for each swl and wave period, the wave generator stroke was varied 

 slightly until the most severe wave condition relative to armor stability was 

 obtained. These wave conditions were then incorporated into the hurricane 

 storm-surge hydrograph and the abbreviated storm-surge hydrograph. Plates 1 

 and 2 show the hydrographs which were used in the revetment stability tests. 



Method of construct- 

 ing revetment sections 



10. Model revetment sections were constructed to reproduce, as closely 

 as possible, the results of prototype revetment construction. Bedding mate- 

 rial, dumped by bucket or shovel, was compacted and smoothed to grade with 

 hand trowels in an effort to simulate the natural consolidation that would 

 occur during prototype construction. With the bedding material in place, the 

 underlayer was added by shovel and smoothed to grade by hand or with trowels. 

 Exposure of the underlayer to excessive pressure or compaction was carefully 

 avoided. The row of stapods (each stapod weighed 10,000 lb on all test sec- 

 tions) was positioned by hand on the bedding material or underlayer, depending 

 on the revetment alternative. Armor stone cover layers were constructed using 

 random placement; i.e., stones were individually hand-placed, but no inten- 

 tional interlocking or special orientation was achieved. 



Test Setup 



Revetment stability tests 



11. A typical revetment stability test consisted of subjecting the re- 

 vetment and seawall test section to attack by waves of a given height and 

 period for a specified time duration. The wave conditions, water levels, and 

 time increments were determined by the hydrograph selected for testing. Test- 

 ing time was accumulated in 30-sec (model time) cycles; i.e., the wave gener- 

 ator was started, run for 30 sec, and then stopped. Use of this procedure 

 ensured that the structures were not subjected to an undefined system of waves 

 created by reflections from the model boundaries and wave generator. After 



12 



