4717 EVERGREEN WAY 2016-01-01 MF Import

; M �� , "'I � � y � p O C f+ N y M .,,i K n W.. a � o After overexcavation/strip�ing has been performed to the satisfaction of the geotechnical ro y � engineedengincering geolog�st, the upper 12 mches of exposed ground should be recompacted � x to 90 percent of the Modified Prcetor Maximum Density usmg ASTM:D 1557 as the standard. ro � If the subgrade contains too much moisture, adequate recompaction may be difficult or � � inpossible to obtain and shoul� probably not be attempted. In lieu o(recompaction, the area � ;� g to receive fill should be blanketed wilh washed rock or quarcy spalls to act as a capillary break x y � ,_ between the new fill and the wet subgrade. dy y After recompaction of the expnsed ground is tested and app.�oved, or a free-draining rock $ o y , course is 1aid, strucWral fill may be placcd ', attain desired grades. Swctura] fill is defined as � � r non-organic soil, acc�ptable to the geotect.nical engineer, placed in maximum 8 inch loose h y _ lifts, with each fift being compacled to 95 percent of the Modified Proctor Maximum Deasity � y usin g ASTM:D 1557 as the standard. The top of the compacted fill should extend horizontally ! outward a minimum distance of 3 teet beyond the location of the perimeter footings or pavement edge beCore sloping down at a m<ximum angle of 2Si:1V (Horizontal:Vertical). The contractor should note lhat any proposed fill soils must be evaluated by Associated Farth Sciences, Inc. prior to their use m fills. This would require that we have a sample of the __ material 48 hours in advance to perform a Proctor test and determine its field com�action standard. Soils in which the amount of fine-grained matr.rial (smaller than No. 200 sieve) is - greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered mois;ure-sensiuve. Use of moisturc-sensitive soi� in structural lills should be limited to favorable dry weather conditions. Some of the onsite soils contained significant amounts of silt and are considered moisture-sensitive. In addition, constructicn eyuipment Uaversing the site when the soils azc wel can cause considerable di�wrbance. If fill is placed �� -- during wet wea.ther, or if proper compaction cannot be obtained, a select material consisting of �r clean, free-draining sand or gravel should be used in lieu of onsite material. Some free- draining soil may be obtainable frem potential cut areas within the northeastern portion of the 1 ' _ property. Frce-draining fill consists of non-organic soil with the amount of fine-grained ��. matenal hmited to 5 percent by weight when measured on the minus No. 4 sieve fraclion. �� _• A representative from our firm should inspect the stripned subgrade and be present during placement of structural fill to observe Ihe work and per�orm a representative number of in- �� place density tests. In this way, the adequacy of the earthwork may be evaluated as filling I �� ' progresses and any problem area; may be cortecte:d at that Iime. It is important to understand , that taking random compaction tests on a part-time basis will not assure uniformity or acceptable performance of a fill. As soch, we are availabie to aid the owner in developing a � suitable monitoring and testing program. �� S.0 FOUNDATION� + �� Spread footings may be used for building support when founded on Ihe existing dense fll soil " � or structural fill placed as previously discussed. If footings arc to be (ounded in the existing i fill soils, the upper 1 foot of the fooung subgredcs should be recompacted to a minimum of 95 percent of max�mum dry density, using a hoepac compactor or a v�bratory roller, if wider �I �� footing trenches are excavated. This compaction is reqwred to densi(y any loose or sofl areas l and to help identify any unsuitable areas within the exisung fill. Compaction must therefore be performed under the observation of Associated Earth Sciences, Inc.'s field engineer so that any problem areas ca.n be cortected prior to footing placcment. We recommend that an allowable bcaring pressure of 2,C00 pow ds per square foot (psQ bc utiliud for design purposes, 6