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Grifin Realty SA, Inc.-Geotechnical Investigation <br />Uiw/Crandall Project 70131-7-0261.0001 <br />July 8. 1997 <br />planned excavated level should be of sufficient strength to adequately transfer the imposed loads <br />to the surrounding soils. <br />The frictional resistance between the soldier piles and the retained earth may be used in resisting <br />the downward component of the anchor load. The coefficient of friction between the soldier piles <br />and the retained earth may be taken as 0.4. (This value is based on the assumption that uniform <br />full bearing will be developed between the steel soldier beam and the lean-mix concrete and <br />between the lean-mix concrete and the retained earth.) In addition, provided that the portion of the <br />soldier piles below the excavated level is backfilled with structural concrete, the soldier piles <br />below the excavated level may be used to resist downward loads. The frictional resistance between <br />the concrete soldier piles and the soils below the excavated level may be taken as equal to 400 <br />pounds per square foot. <br />Lagging <br />Continuous lagging will be required between the soldier piles. The soldier piles and anchors <br />should be designed for the full anticipated lateral pressure. However, the pressure on the lagging <br />will be less due to arching in the soils. We recommend that the lagging be designed for the <br />recommended earth pressure but limited to a maximum value of 400 pounds per square foot. <br />Anchor Design <br />Tie-back friction anchors may be used to resist lateral loads. For design purposes, it may be <br />assumed that the active wedge adjacent to the shoring is defined by a plane drawn at 35 degrees <br />from the vertical through the bottom of the excavation. The anchors should extend at least 15 feet <br />beyond the potential active wedge and to a greater length if necessary to develop the desired <br />capacities. <br />The capacities of anchors should be determined by testing of the initial anchors as outlined in a <br />following section. For design purposes, it may be estimated that drilled friction anchors will <br />develop an average friction value of 600 pounds per square foot. Only the frictional resistance <br />developed beyond the active wedge would be effective in resisting lateral loads. If the anchors are <br />10