(2) Testing. Extensive tests were made on the clay before incorporating in design. It 

 was found that no flow occurred until the pressure reached 6,500 psi (Marcy, 1935). 



(3) Model Study. None. A model study is underway at U.S. Army Engineer 

 Waterways Experiment Station Testing Laboratory (WES), Vicksburg, Mississippi, in 

 connection with increasing the harbor capacity within the breakwaters. 



(4) Instrumentation. None. 

 g. Structural Performance. 



(1) Performance. No indication of failure, although a single capstone in various 

 locations has been upended due to wave action. In 1968, at one point near the eastern end 

 of the middle breakwater, a ship struck the breakwater from the ocean side, dislodging 

 several stones (Fig. 45). Since no further damage was apparent, no repair has been 

 undertaken. Settlement due to breakwater construction has been negligible. 



**', ''WJ'. #'"'- 



Figure 45. View on ocean side of middle breakwater showing displaced capstones 

 (August 1973). 



(2) Maintenance. None to date. 

 h. Effect of Structure on Environment. 



(1) Physical. No appreciable accretion or scour in breakwater area. Harbor and 

 charmel remain at dredged depths with Uttle maintenance dredging. 



82 



