4202 CRESCENT AVE 2016-01-01 MF Import

Sep 28 00 12:36p GEOTECH COHSULTf1nT5, InC. (4251747-8561 p. 6 Lepecy Devefopment JN 00378 SepOember 27.2000 Pege 8 of wmpadible granular fill, such as aushed rock, should be placed over the vapor retarder or barrier for protedion. Sand is not recommended by ACI for use as the proDection layer. We rewmmend prxf-rolling slab areas with a heavy Wdc or a large piece of construction equipment prior to slab construction. Any solt areas encountered during proaf-rolling should be excavated and replaced with seled, imported sWdural fill. ROCKERIES We ar�tiapate that rockeries will be uaed in the site development. A rockery is not intended to function es an engineerod atruduro to resist Ieterai earth pressures, as a retaininp wall wouid do. The primary function of a rockery ie to cover the expoaed, excavated suAace and ihereby reterd the erosion procass. We recommend limidng rodceries to a height of 5 feet and plaang them against only dense, competent, netive soil. We fuKher racammend that all rocks used In the rodcery be at least of 3-man sae. The consttuction of rockeries ia, to a large extent, an art not entiraly controllabk by engineering methods and standards. It is imperaUve that rodceries, if used, are construcied with aro and in a ' proper manner by an experiencQd contraetor with proven ability in rodcery construcdon. The , rockeries should be consVuded wifh hard, sound, durabb roefc in axordanoe wRh accepted local ' practice. Soft rock, or rock with a signficant number oi fraetures or inGusions, should nat be used in order to limit the amount ot maintenance and mpair needed over time. Provisions tor maintenance, such as access to the rodcery, shouid be considered in the design. In genenl, we recammend that rockeries have a minimum dimension of one-third the heigM of the slope wt above them. Tiered rockeries aro not recommended, unlasa there is sufficieM apace to consWct • j upper Uer� that do not exert lateral presaure on the lower tiers. The baae of a tlered rockerYs i upper wall shoul�i be set badc from the rear of the lower rocks an amount equal to the haipht of the i lowertiers. IXCAVAT/ONS AND SLOPES Excavation slopes should not exceed the limits speafied in local, state, and natianal govemment safety regulattons. Temporary wts to a depth of about 4 faet mey be attempted vertically in unsaturated soil, 'rf thera are no indicatlons of slope instabilityr. However, vertical cuts ahauld nat be made near property bounderies, or existing udlities and structures. Based upon Waahington AdmfNstrative Code (WAC)296, Part N, the soil at the subject aite would generaly be deasified as Type 8. Therefoce, temporary cut slopes greater than 4 feet in height cannot be exeavetad at en indinadon staeper than 1:1 (Horizontal:Vertipq, extending con8nuously between the tca end the bottom of a cut. Tha above-recommended temporary slope inclination is based an what has been succes�ful at other sites with similar soil condi�ons. Temporary cuts are those that will remein unsupported for a relatively short duration to allaw tor the construction of foundations, retaining waUs, or utilities. Temporary cut slopes should be proteded with plastic sheeting during wet weather. The cut slopes should also be backfilled or retainad as soon as possible to reduce the poteMial for instability. Please note that loose soil can cave suddenly and without waming. Excavation, foundation, and utility contractors shouid be made especially aware of this poteMial danger.