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<br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />I <br />~ <br />I <br />I <br /> <br />. <br /> <br />... <br /> <br />. <br /> <br />Figure 5 shows the standard drawing for wire-enclosed riprap used <br />by the Bureau of Public Roads, Denver Regional Office. The drawing <br />shows details for a 5-foot square basket, 1 1/2 feet deep, made of 12 1/2 <br />gage galvanized fencing. The ends of a 5 x 8-toot length ot fencing are <br />turned up to form the bottom of the basket. A similar section inverted, <br />forms the top and the other two sides. The sectiOlls of wire are held <br />together with four ties of 50. 9 gage annealed wire, aDd the corners ot <br />wire baskets are fastened at 8-inch intervals with No. 12 gage galvanized <br />wire or with 10. 9 gage galvanized hog rings. 'rhe rock filled baskets <br />make contact with each other are are fastened together at 1-foot intervals. <br />A steel stake 5 feet or more in length is dtrven into the sUbgrsde through <br />the center of each basket 'to anchor the basket to the slope. A different <br />method ot fabricating the baskets is shown in tigure 5A. <br /> <br />Wire-bound rock sausages suggested by Posey (10) are a form of wire- <br />enclosed riprap. Rock-tilled gabions, which are similar to the sausages, <br />have been in use for many years in foreign countries. AD Italian firm <br />supplies a patented prefabricated wire gabion. The U.S. Forest Service <br />has a specification for wire-mesh gabions. The Forest Service gabion is <br />a rectangular basket which is furnished by a contractor in the size or <br />sizes specitied. <br /> <br />The discussion of the extent of stone blanket in section 2.1.2 also <br />applies to wire-enclosed riprap. <br /> <br />2.4 - Design of Grouted Ri~ra~ <br /> <br />Grouted riprap is used where stone of suitable size for other types <br />of riprap are not available. Wire can be embedded in the riprap to <br />increase the tensile strength ot the protective cover. The finished pro- <br />tection is rigid and has little strength. For this reason, the embankment <br />protected IlUSt provide adequate support and the edges of the riprap cover <br />must be protected trom undermining at the toe and at the terminals. Design <br />data are lacking for determining the specific thickness of the cover. The <br />grouted riprap maybe left with a rough surface by brushing the grout until <br />trclll one-fourth to one-half the depth of the stone is exposed. <br /> <br />Weep holes should be provided 1Il the blanket to provide rapid relief <br />of any hydrostatic pressure behind the b1naket. Filter blankets are <br />generally necessary as in the case of other types of riprap. <br /> <br />2.5 - Design of Concrete Riprap in Bags (SaCked Concrete <br /> <br />Concrete riprap in bags e;eneral1y consists of approximately 2/3-cubic <br />foot at class C concrete <3 1/2 bags cement per yard) in a burlap bag or <br />in a cement sack. This type of riprap provides a heavy protection regard- <br />less of the requirements of the site. The riprap has little flexibility, <br /> <br />11-11 <br />