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- �� : .. <br />. - �.�; Dr �i�ng_�U � b�i76i >s8i lU , Bio � I� L' �_, �_��.; , <br />_ <br />-�,.,_ � _.,... <br />� ,, �� _ i <br />4 � <br />i�l� i <br />SPECIFICATIONS FOR RE(NFORGED WALL <br />General <br />1. The contractor shall have an approved set of plans and specifications on sile at all times during the consiruction of the <br />wall. The wall layout is the responslbifity of the contractor. <br />2. Nelson Geotechnical Associates (NGA) should observe and mor.itor the construction of the wall on a full-time basis. <br />3. Stratagrid geogrid or equivaleni sha�l be used for this project. Aii geogrid and faci�g materials shall be approved by <br />NGA prior to installation. <br />4. The contractor may use longer geogrid lengths than the design sections for ease o( eonstruction. The geogrid iengths <br />may not be shorter uniess approved by the geotechnlcal engineer, <br />Suborade Preparatior <br />1. TFe ground shall be prepared by removing surfiGai unsuitable soi1, down to dense, inorga�ic, native soils as approved <br />by NGA. <br />2. A generaliy level bench unth a minimum width equal to the design fength af the geagrid is required for piacemeni of the <br />reinforced fiii. <br />3. The excava5on shall 6e cleaned of all e�ccess malerial and protected, as necessary, from constructior, traffic ia maintain <br />the iniergrity oi 1he subgrade. <br />4. The 6ase of the excavaiian shalf be deep enough to satisfy a minimum embedment of 78-inches. <br />5. The Ultra 6locks shal! be supported on a minimum 6-inch thick 2-inch crushed rock pad extendi�g a minimum of one <br />foot in iron[ and behind tne wail. � <br />Geoqrid Placement <br />1. Th�e reinforcement shali be rolled out, cut to 4ength, and laid at the proper elevation, lxalion, and orientation, <br />Orientation of ihe reinforcement is of exVeme importance si�ce geogrids vary in strangth with roil diredion. The <br />con[ractor shali be responsible for ihe correct orientation. <br />2. Geog!id shzii be placed at the location and etevations sho+m on the plans. The geogrid length is measured from the <br />back of the wall. <br />3. Prior to placing the �ili, (he geogrid shall be puiled to remove the slack and stretched by hand uniil taut and free of <br />wrinkles. <br />Fill Placement <br />1. Structural fill, consisting of granular import soits or on-site materiai no greater than 3-irtches in size,shall be used for <br />Qrain trackfifl. if larger rock is used in the fiil, addilional layers of aeogrid may need to be used in the reinforcement. ?he <br />j� contractor sha!I prevent damage to the geognd by placing the first lift of structurai fi!i with at least a �-foot thickness. NGA <br />sha(1 apprcve tf�e material placed in ihe reinforced zone, befo;e pfacement. <br />2. S'ru�,u;al ft1; shall have parameters equal to or better than those stated for the reinforced wali fiii below with less than <br />25 pe�c=nt passirg ?he number 200 sieve. NGA may albw a higher sil, content based on review of the waH design and <br />proposed fiti parameters. <br />3. Soii density tests sha;l be per�ormed as designated by NGA. <br />4. Fil; sols in the waif area sha!( be oompacted tc at least 95 percent of the Maximum Qry Density (MDD) as determined <br />by ASTf,4 G1557. <br />5. : ne ;o:? sha+.� be p;aced :� r��afiveiy uniform horizonta! Irfts noi exceeding '10 or 12 inches in thickness. The lift <br />thickness shali not exceed the manufacturefs recommended depth for Ehe compactive device used on lhe project. <br />Drainaoe <br />1. R spec�c drainage system is shotivn on the gtans. Altemative drains can be �sed based on condRions found in the field <br />and the material used within the reinforced zone. Changes to the drairtage sys!em should 6e approved by NGA prior to <br />placement. <br />2. A drainage 6lanket 12 inches in width sha(I be instalied directly behind .he block tacing and shall consist of i'i14-inch <br />clean crushed rock. All of the drainage materials shall have a fi�es content no greater than 5 percent passin� the number <br />206 sieve. A 4-inch rigid periorated pipe embedded in a minimum af one foot of pea gravei or washed rock and wrapped <br />with filter fabric shall be instafled at the boriom of the drafnage layer <br />3. Surface water shall not be ailowed to pond in or near the reinforced fii! zone during or after construcfion. <br />4. Suitable clean-outs shail be installed every 50 feet or at strategic loca6ons for future maintenance. <br />5. Surface water shall not be ailowed to reach the drainage layer. <br />Desipn Parameters <br />Reinforced Wail Fill: 32 degrees, D PSF, �20 PCF <br />Ret3ined Backfill: 32 degrees, 0 PSF, 12Q PCF <br />Foundation Soil: 32 degrees, 0 PSF, 120 PCF <br />External Stability of Wall <br />tJinirnum Factor oi Safety against Base Sliding: 1.5 <br />Minimum Factor of Safety against Overtuming: 2.0 <br />Minimum Factor of Safety against Bearing Capaciry: 2.0 <br />interrtai Stabilitv of VJall <br />Minimum Factor oi Safety on Geogrid Strength: 1.5 <br />Minimum Factor of Safety on Geogrid Pullout: 1.5 <br />Soil-Geogrid Inieraction CoefficienC 1.0 <br />Percent Coverage of Geogrid: i00 Percent <br />fnspection <br />Wall construction shail be observed by NGA on tull-Gme <br />basis during consVuclion. <br />yA� m <br />W J <br />G <br />O <br />� m <br />•� c <br />� 'o, <br />(„+" O <br />� M <br />o+ `- <br />� � <br />� N <br />..l <br />'� <br />� <br />z� <br />z Z <br />V <br />W (n <br />� � <br />O F <br />W � <br />� U <br />Z � <br />o� <br />� <br />N � <br />J <br />� � <br />� � r' <br />�, <br />�`�. <br />� <br />� �t <br />��' 1 <br />,�"_. t <br />Y :'___. <br />� .. <br />� <br />E- <br />N <br />� <br />a <br />� <br />� <br />w <br />� <br />� <br />N <br />� <br />W <br />w <br />Z <br />C7 <br />Z <br />IJI <br />� <br />Q <br />U <br />� <br />i <br />� <br />�i <br />H <br />O <br />W <br />� <br />.� <br />� <br />❑ <br />� <br />� L <br />� � <br />a cu <br />o � <br />L <br />L1. 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