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��r <br />A�x <br />�H5f~i� <br />yxr�i <br />�H� <br />�fAN <br />��� <br />oH <br />��g <br />S]Y C(] <br />9Ht�f <br />t� �' <br />g�y <br />c)�C[�n <br />�O� <br />� <br />1 <br />I �� <br />D.�VID L. NEL50N AND ASSOCIATES, WC. <br />Consulting Enginccrinp Gculugy� <br />Febcuacy 8, 1990 <br />Pcoiect No. 0890 <br />Page 8 <br />constzuction, and the type of soil used behind the vall. Fox planning <br />puzposes foz Eixed ot non-ylelding valls, ve xecoomend that the "at cest" <br />condition should be assumed, and that an equivalent fluid pcessu=e of 50 <br />pounds pec cubic foot (pcf) be used Eoc design pucposes. Foc yielding valls, <br />such as cantilevez valls, the "active" condition may be assumed and an <br />equivalent fluid pcessuze oE 35 pct bz used. To develop the "active" pcessurz <br />condition, the vall must be alloved to yield ahout its base a distance of <br />about 0.001 times its total hetght. <br />The effect of sutchatges, such as ttaffic ox floox loads, should also be <br />considexed. Foz a uniEoLmly distzibuted load behind the vall, a coczespondina <br />unifo=mly distxibuted piessuze equal to 30 pezcent oc 50 pe=cent of the <br />succhaxge should be added to the latezal soil p=essuLe Eot yielding and non- <br />yielding,valls, cespectively. If filling behind the vall is peLtotmed, <br />compaction of backtill vtthin one-half oE the vall embe�iment he[ght behind the <br />vall should be pezfocmed vith light equipment such that the vall is not <br />adversely stcessed. <br />Foc planning putposes, design foc late=al eatth piessuzes acting on foundation <br />valls could be cesisted in the n=tive giacial bzazinq suils by use of a <br />combination of foundation base friction and passive pcessuze. A base fxic:ion <br />coeEficient of 0.95 is considecei appcopxiate vithin the advanc= glacial <br />outvash deposits. A passive equivalent fluid pLessuze of 350 pcf may he used <br />Eoi native advance glacial outvash deposits oc stzuctucai Ei11. Nhexe valls <br />ace located neaz slopes, the gxound sucface in fcont of the vall should be <br />level foc a distance of at least 3 tlmes the depth of bucial oE the Euotinq, <br />to allov the above passive pLessuces. Othezvise, a reduction of passive <br />pcessure vtl! be [equiced. Specific zeductions in passlve pcessuxe could be <br />developed once the dovnslope geometzy and buildiny designs aze knovn. An <br />appcopclate Eactoc oE saEety should be applied to the above base fciction and <br />passive values to zesist sliding. <br />The a6ove values assume the p=esence oE the soils encounteced [n uur <br />