a geometric assembly configuration, and subsequently conducted performance and 

 evaluation tests. The Goodyear Tire and Rubber Company has investigated 

 extensively the use of modular building-block elements formed by securing 

 together bundles of tightly interlocked scrap tires with high-strength rope or 

 cable, but the company has not patented nor commercially used scrap tires in 

 this form (Candle, 1974). The information from this research has been made 

 available for public use. Kowalski (1974) tested a simple mat-type floating 

 breakwater of scrap automobile tires, constructed in various layers of mats 

 fastened together. Harms (1979a) experimentally investigated a concept known 

 as the "Wave-Guard" (now the "Pipe-Tire" structure) which differed from both 

 the Wave-Maze and the Goodyear concept. Structural components of massive logs 

 (telephone poles, concrete beams, etc.) were utilized with the scrap tires 

 being threaded onto the poles, which were in turn connected with conveyor 

 belting. While an almost limitless variety of assembly configurations appears 

 possible, these basic designs constitute those which have received the great- 

 est attention from an experimental investigation standpoint. 



1 . Wave-Maze Scrap-Tire Floating Breakwater Concept . 



Stitt and Noble's (1963) patented Wave-Maze scrap-tire floating breakwater 

 was subsequently investigated for performance effectiveness by Kamel and 

 Davidson (1968) and Noble (1969, 1976). The basic component of the breakwater 

 is used truck tires, some of which are filled with flotation material such as 

 polystyrene or polyurethane. The construction consists of both a top hori- 

 zontal layer and a bottom horizontal layer of truck tires bolted to a center 

 element of vertical tires arranged in a triangular pattern (Fig. 71). Each 

 line of tires in plan view is approximately 4.5 feet wide. According to Noble 

 (1976), the breakwater should be constructed so that the total width of break- 

 water is at least one-half of the length of wave to be attenuated. If wave 

 heights are greater than about 4 feet, additional tiers of tires should be 

 added so that the depth of the Wave-Maze exceeds the wave height to be atten- 

 uated. Truck tires were recommended instead of automobile tires because the 

 extra sidewall plies in the casing help reinforce the connections. At least 

 two layers of reinforcement material (sections of tire casings or conveyor 

 belting) should be added inside the tires at each bolted joint. Hot-dip 

 galvanized bolts and washers should be used for all connections in saltwater 

 environments. 



a. Wave Attenuation Effectiveness . The Wave-Maze physical model tested 

 at WES by Kamel and Davidson (1968) was constructed of 6-inch-diameter tires 

 assembled in the same fashion as in the prototype with one exception — the 

 method of fastening the tires together. In the prototype, the tires were 

 fastened together by bolts; however, because of the size of tires in the 

 physical model, wire connections were used instead of bolts. The precise 

 effects of this connection method are unknown, but it is believed to allow 

 relatively consistent comparable flexing of the assembly. 



The flotation system in the prototype was reproduced in the model, using 

 commercial Styrofoam that was cut and placed inside the model tires. Floating 

 height of the test structure varied according to the flotation material used 

 in either all the tires or the desired number of tires. The assembly of tires 

 remained the same throughout the tests; therefore, the porosity of the model 

 Wave-Maze was the same for all the test structures — about 80 percent. The 

 definitive sketch for the two-dimensional model is shown in Figure 72. 



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