1901 MERRILL CREEK PKY 2018-01-01 MF Import

weights from about 750 to 5,000 pounds (3- to 5-man rocks as defined by Associated Rockery Contractors). The rock density should not be less than 160 pounds per cubic foot. The lower 4 to 6 feet of the rockery should be constructed using 4- to 5-man siu rocks. Rock selxtion and placement should be accomplished to reduce the number and size of voids. In the exposed face of the walt, no openings gteater than 6 incha in dimension in any direction should be perrtutted. Rock courses should be gradational in size from bottom to top with the largest rocks of uniform size being placed for the lowat two courses. The contact between rocks should slope downward to the back side of the rockery. Each course of rocks should be seated tightly and evenly on the course beneath. After seating each course of rock,voids between the rocks should be chinked on the back with quarry spalls to eliminate passage of backfill (�� material. Backfill immediately behind the rcekery should consist of quazry spa(ls. The spal(s should consist of well-¢raded 3/4 to 4-inch cnuhed rock and should be durable, uncontaminated by soil or other debris, and not readily susceptible to weathering. The quarry spall fill should be placed to a width of not less than 18 incha between the rockery and the face of the cut. The spalls should be placed and compTcted in lifts to a level approximately 2 inches below the top of each course of rocks as they are placed, until the uppermost course is placed. My bac�ll material falling onto the bwring surface of one rock � course must be removed before setting the next course. Rcek placerttent should be such that each rock above the base course will be supported on two rocks in the neact lower row. � A perforated drainpipe should be embedded in the baddll at the base of the rockery. This drain should discharge to the storm drain system or daylight at a location which wiil not impact �,;ti slope azeas at the site. Rockeries should be instaUed by a qualified contractor experienced in rockery construction. The construction should be monitored by a repraentative of our firrtt. Crib Walls Interlocking crib walls could be considered to retain any of the cut slopa or fill embanlanents cunently planned in the project area. This type of ntention system consists of ' elements, typically made of precast concrete or metal, that interlock to fonn a boz. Clean granulaz backfill material is placed and compacced inside the box. Horizontai loads from the slope being retained are resisted primarily by gravity. This type of retaining wall can withstand some settlement. The amount of settlement depends on foundation suppott conditions and construction techniques. Significant ezcavations are required for the construction of crib walls in cut areas. The width of the excavation is typically on the order of 1/2 to 2/3 of the height of the wall. We expect that the temporary ezcavation will be sloped at about O.SH:1V where the cut is made in unweathered glacial tiil soils and 1H:1V where the cut is made in other soils. G e o E n { i n e e r s 13 Fik No. 116P006J7•1130/111297