with externally strain-gaged armor during this same time period. Timco and 

 Mansard developed their strength scaling relation during this period as 

 described previously. 



25. The Crescent City Prototype Dolos Study Workshop (Howell 1985) was 

 instrumental in setting the stage for the bulk of the current CAU design 

 philosophy. At the workshop, the concept of characterizing the structural 

 response of a dolos as two moments and a torque was introduced. It was the 

 consensus of the attendees at the workshop that these parameters would be 

 measured at the shank- fluke interface, where stress concentrations cause the 

 highest stresses. Also, due to the random boundary conditions and wedging 

 forces in the armor layer, it is impossible to develop an unambiguous 

 relationship between the stresses at mid- shank and the stresses at the shank- 

 fluke interface. So mid-shank instrumentation could not be used to determine 

 the maximum stress at the shank- fluke interface. 



26. Also at the workshop, McDougal and Tedesco showed initial results 

 from an FEM numerical model for prediction of the stresses in a single dolos. 

 This work was later extended to include a wave force numerical model and a 

 rigid body stability model (McDougal, Melby, and Tedesco 1987). These numeri- 

 cal approaches based on wave force models relied on semi-empirical determinis- 

 tic wave-force-on-cylinder equations with deterministic boundary conditions. 

 Crescent City Prototype Dolos Study 



27. Following the 1985 workshop, a detailed plan was formulated for 

 the Crescent City Prototype Dolos Study. The Crescent City study was broken 

 down into individual tasks, each carefully designed to produce products that 

 would feed into the dolos design procedure and mesh with the other study 

 products. The tasks are listed in Table 3. Other than the design procedure 

 development, the tasks are divided into three groups: (a) prototype data 

 collection, (b) physical model tool verification, and (c) deterministic dolos 

 analyses . 



28. The data collection task included collection of free surface 

 elevation, dolos strains from 14 instrumented dolosse, photographic records of 

 the breakwater and instrumented dolosse, and pressure signals from pressure 

 gage arrays inside the breakwater and just off the breakwater toe. The 

 deterministic tasks consisted of analyses using primarily FEM models. The 

 results of all of the tasks were used in the design procedure development. 



15 



