10200 19TH AVE SE Geotech Report 2018-01-02 MF Import

Ne reco^unen�i �at the capillary break consist of 4 w 6 inches of crushed rock or clean, well-graded sand and gravel compactad to at least 95 percent of the maximum dry density �.:STM D-1557). The capillary break material should have a mazimum pazticle size of 3/4 iach, with no more than 80 percent passing the No. 4 sieve and less than 5 percent fines (material � passing the U.S. Standazd No. 200 sieve). A vapor barrier is not required unless floor coverings ; i sensidve to possible upwazd migration of moisture aze to be installed. A vapor barrier sucb as plastic shceting between the floor slab and ihe capillxry break can be used to provide an added protection against upwazd migration of moisture into the slab. We understand that cracking has ' occuaed in some of the Costco Wholesale floor slabs. It is our opinion that a likely contributor is the lazge wheel loads from the forklifts that aze used to move suppiies. A 12-inch ihicr ' capillary break fill section (consisting of the cnuhed mck or sand and gravel describod above) . • would provide a higher modulus of subgrade rezction and therefore p:ovide a stiffu subgrade. 7'he stiff subgrade wouid allow less deflection of the floor slab and proyide bettu resutance to cracking. LATERAL LOADS Lateral loads can rie resisted by passive resistance on the sides of the footings and by friaioa on the base of the footings and floor slab. Pusive resistance may�be evaluate i usiag aa equivalent fluid density of 300 pcf (pounds per cubic foot), 2ssumir�g that the soil azou�d , the footings for a discance of twice the footing depth consists o: either dense nadve dll or compacted swctural fili. Thc top of the triangulaz passive pressure uis!ributien shouid begin at the bottiim of adjacent floor slabs or paving or befow a depth of 1 foot where the adjacent uea - is unpaved, as appropriate. Friaional resistance can be evaluated using 0.4 for the coefficieat - of base friction against feotings and the huilding slab. The above va:ues incorpo:ate a factor of • � safety of about 1.5. RETAINING WALLS 'll�e building will have loading dock walls and other retair.ing walls may be required for grade uansitions. We recommend that cantilevered retaining walls and loading dock wails be designed for lateral pressures based on zn equivalent fluid density of 35 pcf, provided that the walis aze free to yield during backfilling. Walls that aze restrained from movement during bacidilling should be designed for•a lateral earth pressure corresponding ta an equivalent fluid ' density of 50 pcf. A surchazge conesponding to at least an additional 2 feet of backfill should be includecl in the design of retaining walls that will have veh iculaz uaftic at the top of the walls, depending un the anticipated wneel loads and proximity of the wheels to the wall. Fill placed against the w:ills shouid be comQacoxl to between 90 and 9? percent of maximum density rather than the 95 percent indicated for the remai�ing structucal fill within the building azeas. Care must be exercised by the conttactor :o avoid overcompaction. Bac�ll against the wall should consist of clean, free-draining granulaz material wntaining less than G e o E n g i n e e : : 8 Fle No.0975-017-R73/062993 �