PART II: DOLOS DESIGN PROCEDURE 



Overview 



32. Of the loads listed in Table 1, the three primary loading mechan- 

 isms are static, pulsating, and impact. But the structural designer requires 

 an overall maximum design stress. Because the boundary conditions and the 

 loadings are random, this design stress must be based on a single design prob- 

 ability function. This probability function will be some combination of the 

 static, pulsating, and impact response principal stress probability 

 distributions . 



33. It has been shown by Melby and Howell (1989) and Melby, Rosson, 

 and Tedesco (1990) that the static stresses measured in the Crescent City 

 dolosse were close to the critical strength of the concrete. Because of these 

 high stresses in large slender armor units, there is little residual strength 

 in the units to resist pulsating and impact loads. Pulsating loads have been 

 shown to be small relative to static loads and would therefore not be expected 

 to affect the design stress significantly. But impact loads due to dolos 

 rocking and projectiles in the armor layer could be large and the large 

 slender unreinforced dolosse do not have the capacity to resist these loads. 

 This design procedure is therefore focussed on the probabilistic combination 

 of static and pulsating stresses only, for the design of large dolosse. 

 Future revisions will incorporate the impact response to facilitate the 

 strength design for smaller and/or reinforced dolosse. 



34. Some probability distributions used in this report are based on 

 the normal distribution. 



p(x) = exp 

 J2ns 



—i } 



(1) 



The manipulation and combination of these distributions can be mathematically 

 laborious but can be done quite easily numerically. Thus, the microcomputer 

 program CAUDAID has been developed to automate the manipulations of the 

 probability distributions. This report provides a detailed discussion of the 

 analytical methods and assumptions underlying the CAUDAID algorithms. 

 Appendix A provides a discussion of the program CAUDAID and gives a design 

 example showing program input and output. 



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