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1 � <br /> ( footings along thc north and «cst sidc of tlic huildin� must hc undcrlain h� at Icast 3 fccl uf <br /> strucwral fill compactcd to at Icast 95 perccnt MDD. <br /> I 4. Tlu poorly perfomiine and loosdsofl undocumented fill in thc SOUlI1N'C51 porlion of thc <br /> building footprint should he rcmo��cd and rcplaccd with structural fill crnnpacicd to at Icasl 95 <br /> � percem MDD. <br /> 5. 1ew fill placcd in the arcas sutrounding tlie huilding, especiall�• on the north mid ���cst sides, <br /> aill also induce setticmcnt of thc loose soil: ho��e�•er, thcse scnlcmcnts �eill likcly bc <br /> � managcable, provided suflicicnt time is allmvcd hct�eeen fill placemcn� and ins�allation of any <br /> settlement sensitive imprm�ements such as graviq�Ilo�c u�ilities. <br /> G. Pootings located in ihc older structural fill areas should have�he espnsed suhgradc rccompactcJ <br /> 1 to at least 95 perccnt MDD prior to placing reinforcine steel and crnicrcte. <br /> 7. Tlie fill uscd at tlie site is derived Gom glacial till ihat consisis of silh sand ���ith gravel. This is <br /> I a high qualiry material and should providc a competent base for pa�•cmcnt support, provided thc <br /> pavement subgrade can be compacted to a finn and um•ielding condition. Such compaction can <br /> be achieved in dry �ceather conditions. During wet �eeather conditions, ilte till malerial may <br /> � become o��erwet and be susceptible to disturbance. <br /> 8. Tlie building pad should be covered with at least 12 inches of crushed gravcl or a miawre of <br /> I sand and gravel,sudi that adequa�c working conditions esist durine ihe wet winler tnonths. <br /> 9. After site grading is completed, the planned pavement areas should be protectcd from traftic. <br /> Haul routes should be protected with a laycr of crushed rock over a geotertile separalor. <br /> � Equipment should be kept ofi'as nucli of the surrounding pavement areas as possible. Asphalt- <br /> trcated base should be considered around the building�shcrc equipment will be routed in order <br /> Ito protect the subgrade soils, if wei weather conswction is planned. <br /> These geotechnical considerati�ns are discussed in greater de[ail, and conclusions and <br /> � recommend2tions for the geotechnical aspects of the project are presented in the following sections. <br /> � 4.2 EARTHWORK <br /> 4.2.1 Grading Considerations <br /> The glacial till fill soils at the site consist mosQy of silt�� sand soils. Tliese soils contain <br /> � sufficient fines (material passing the U.S. standard No. 200 sicvc) to be extremely moisture- <br /> sensiti��e and are susceptible to disturbance, especially wfien wet. Silty till soils can absorb <br /> moisture and may be difficult to dq�out eacept during periods of prolonged dq�weather. Operation <br /> Iof heavy equipment or loaded trucks on the [ill fill during wet conditions can be. expected to result <br /> in disturbance ro the subgrade soils. The amount of disturbance will depend to a lazse degree on the <br /> I amount of traffic and severiry of the wet weather. Ideally, earthwork should be undertaken during <br /> e�tended periods of dry �veather when the till soils will b�. less susceptible to disturbance and <br /> provide bcner support for construction equipment. Dry weather construction will help mduce <br /> Iearth�ti�ork cosu and incre�se the potential for using suitable on-site till soils as structural fill. O�r <br /> eaperience at thc site indicates that during the months of June dvough September the on site glacial <br /> l <br /> � G e o E n g i n e c r s � File No. 7tgq.pp..pp-�130105pI0i �� <br /> ��IY <br />