9001 AIRPORT RD Geotech Report 2018-01-02 MF Import

i ' y}�y,fwface Faploratlon, Geobgic Hazard. m�d Pre6minary Geotethnical Engineering Repnrt Sno-Isle Ski!(s Cenrer Addinon Pre1i • Desi n Recommendalinns �erett, Washin ton � Depending on consuvction staging and desued performauce� the crushed base course material may be substituted with asphalt treated base (ATB) beneath ihe final aspba�t surfacing. T�e Isubstituuon of ATB should be as follows: 6 inches of crushed rock �be orsstruc�a� fi 4 inches of ATB� ATB sbould be placed over a property co�acaced/2 to 2 �C� �C�esi of � subgrade compacted to minicnum 95 percent relaGve density, crushed rock to act as a working surface. If ATB is used for coastrucuoa acc�ss a°d stagmS contractor shouldnemov�ea'ffeced areas and eplace them with p oP i�Y p�cP cted ATB pi oT � to final surfacing. I 14.0 DRAINAGE CONSIDERATIONS � Traffic across the on-site�e eforee durmgaz te wo koand econslltn�ctiont thedcontrzacntor shoud otherwise fum suacum• � provide surface drainage and subgrade protection, as necessary. � walls taller than 3 feet should be provided with a Any retaining walis and all perimeter footing ol vin 1 chloride drain at the footing elevation. Drains shouid consist of rigid, perforated, P y 1 e should (PVC) pipe surrounded by washed pea gravel. The level of the perforations in the P P o allow gravryttdisch ge away fro the buildings.�The perforaaonse sho d bfe�locaed onl�e lower portion of the pipe. In addition, any retainia8 or basement walls should be lined w�th a minimum. 12-inch-thick, washed gravel blanket, or bacl�'illed completeIy with free-dra�nwB wall (excluding the fust 1 foo b�low�the surface M Thedrainag�mat cannot be substitnted for the washed gravel blanket drain unless the entire wall backfill is free-drain1nS• Drainage material should tie into the foocing drains. Roof and surface runoff should not discharge �nto the fouting drain system, but should be handled by a sepazate, rigid, tighdine drain. in planninS� exterior grades adjacent to walls should be sloped downwazd away from the co lected by a storm dra n system that dischazges into the soe st rm waterssy t m� Sbould be 15.� LATERAI-WALL PRF.S3URES q11 backfill behind walls or around foundation units shoutd be placed as per our recommendations for structural fill and as described in this section of the report. Horizontally backfilled walls, wu::h are free to yield laterally at ]east 0.1 percent oC�e Fullgrtestrained� � d��gned using an equivalent fluid equal to 35 pounds per cubic fooc (P fl• y �y�ent horizontally backfilleu rigid walls, which cannot yield, should be designed for an � ASSOC/ATED EAR7if SCtFNCES,INC. J�� Page 17 EG/Id-�1I3A5-i'roj��1i31F��