1415 75TH ST SW BASE FILE 2016-01-01 MF Import

J'Donnell, Driqham � Partners, N. W. E-1540 May 19, 1981 Page 9 In transition zones between cut and fill, the fill should be benclied into native ground every two (2) feet in vertical height. The benches should be at les3t four (4) feet in widl-h. This will re�uce, but not eliminate, cracking due to the cut and fill areas. Allowing tlie fills to remain i., place at least tf�trty (30) days before beginning construction will also reduce or eliminate differential crar.king of ti�e slab. In nreas wliere moisture is undesirable a vapor barrier ma� be placed beneath the slab. One (1) to two (2) inchea of sand may be placed over tlie membrane for protection durinq construc- tion. The slab may be isolated from foundations to :educe the possible detrimental effect� o[ differential settlements between the footings and floor slab. Settlements For the anticipated building and Eill loads, we expect that total settlements on the order oE one (11 inch will occur, with this same amount occurring as diEEerential setClements between cut and dcep 1'ills (qreater than five (5) feet in height). This arnount can be reduced approximately one-half (1/2) by allowing the deep £il:�s to remain in place al least thirty (30) days. It i:; expected that the majority ot post construction settlement sl�ould occu,: during construclion and ttie initial loading of the slab. Lateral Forces Short term wind or,seismic forces may be resisted by pas- t;ive pressures, and/or friction between concrete and the support- zng subgrade. Tiie passlve resistance,may be considered as an equivalent fluid load of two liundred seventy-five (275) pounds per cubLc 'oot. Tliis value assumes tliat all footing backfill is compacted in accordance witli th� Site Preparation recommenda- tions in tliis report. A coefficienl of Eriction of tliirty-flve hundredtlis (0.35) may be considered between concrete and soil. Retaining Walls Retaining walls should be designed to resist lateral earth pre:;sures imposed by the soils relained by these structures. , Walls tliat are designed to rotate tiirough a distance oE 0.002 ti.mes tl�e wall heigti� or less sliould be designed to resist lnteral earth pressures imposed by an equivalent f_'uid with a unit weiglit of thirty-five (35) pcf. If walls are restrained at the top from free tnovement tliey sliould be designed for an additional uniEorm pressure ot fiEty (50) psf. ' /" � The above pre�sures assume no hydrostatic forces and a maxiR�m wall height of six (G) feet, and that no surcharge Earth ConsullanLs, Inc. 0�/L.r ..��