of publications concerning the use of fiber reinforcement is given in Howell 

 et al. (1992). 



78. Conventional rebar reinforcement has been used in dolosse and adds 

 significantly to the strength of the units. The advantage of rebar is that it 

 significantly increases the tensile strength of the cross section. The main 

 disadvantages of conventional steel reinforcement are: 



a. Steel must be put in equal amounts throughout the dolos cross 

 section because of the random location of the maximum stress. 



b. Because the loads are unknown, the amount of steel must be 

 overestimated. 



c. In order for the steel to be effective, the unit must crack, 

 thereby allowing corrosive seawater to come in contact with 

 the steel. 



For these reasons, the cost of conventional reinforcing can be prohibitively 

 high. 



79. Pre-stressing or post-tensioning steel tendons within the dolosse 

 has been shown to be effective at increasing the cross -section strength 

 (McDougal, Melby, and Tedesco 1987), but the logistics of economically 

 tensioning the tendons have not been investigated. 



80. Because this design procedure does not quantify the loads on a 

 dolos, specification of conventional reinforcement is not part of these design 

 methods. The design methodology does lend itself nicely to strength 

 enhancement methods, though. The strength enhancements that can be 

 implemented include high- strength concrete, fiber reinforcing, and 

 prestressing or post-tensioning. These enhancements can be implemented during 

 the final design process if the design stress is too high. Follow-on reports 

 that are currently in preparation will investigate strength enhancement 

 alternatives and compare the competing alternatives on a cost basis (Melby and 

 Turk 1992). 



Intermediate Dolos Design 



81. The intermediate design phase, illustrated in Figure 9, will 

 consist of simultaneously measuring the dolos structural response and hydro- 

 dynamic stability in physical model studies, where necessary. The designer 

 must determine if the costs involved with measuring the dolos structural 



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