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�,.�nr... � Y <br /> � � <br /> � <br /> ���� ,. I`:aY!)Y.. <br /> `/^ � <br /> F � �� <br /> �•,r;.. � n,��•.,ny:�,rr... .,:.._. � „+: -::rr>.: -- ;y, •..,•� . <br /> a„�.+,:...,. .�y.t.. '�.',�11f.... ...,aey�-m: . .. � , .... � � �. <br /> Fd � <br /> ��� � <br /> '� � Geo�l:ngineers <br /> ��d , w ; <br /> Q O� � I widths of 7 feet and 18 inches, respectively. The base oE exterior <br /> R1 i <br /> footings should be fowtded at least 18 inches below the lowest adjacent <br /> �H� i "° grade for frost protection. Interior footings may be 12 inches below the � <br /> ~y � � bottom of the floor slab. <br /> � <br /> �� � We recommend a maximum allowable soil bearing pressure of 3000 pounds � � <br /> ytb . <br /> i! per square foot (psf) for footings founded on structural fill or on the <br /> O W medium dense weath�red till. It is critical that site preparation and <br /> -- i � <br /> iy structural fill placement in areas beneath structures be completed in � <br /> �y <br /> conformance with our recommendations in order to limit foundation settle- <br /> menCs. We recommend a maximum allowable soil bearing pressure oi 8000 psf , <br /> I .o <br /> . for design of footings founded on the dense to very dense unweathered � <br /> - "� glacial till or the granular materials encountered below the till. The I <br /> - �� allowable bearing pressures presented above apply to the total of dead and I <br /> �� long-term live loads and may be increased Uy one-third wlien considering I <br /> - � �� earthquake or wind loads. � <br /> ^.-� ; �� We estimate that postconstruction settlements of footings Lounded on i <br /> � ����! � �.y the dense glacial till will Ue less than 1/4 inch. The settlement of i <br /> I footivgs founded on structural fill or a combination of structural fill <br /> ( � ' � <br /> �, ° �,� and weathered till may range from 1/2 to 1 inch, depending on actual <br /> �� foundation loads and the thiclu�ess of fill and weathered till which <br /> � � v underlies the footings. Maximum differential settlements Uetween adjacenL <br /> PA <br /> comparably loaded columns should be less than 1/2 inch wltere there is a � <br /> �1+� �� ' .; gradual transiCion from column footings supported on fill/weathered till �� <br /> � I <br /> and fooCings supported on unweathered till. We estimaLe that the <br /> i ' � � _ differential settlement betwecn exteriar column footings or along i <br /> I �� ' <br /> r I <br /> continuous footings will be less than 1/2 inch in 40 feet where fool'ings i <br /> are supported on dense native soils and/or structural fill. � <br /> I , � '� �� <br /> �� � Loose or disturbed soils not removed from the footi�ig excnvations <br /> i <br /> iprior to placing concrete will result in increased settlement. Due to tlie . <br /> I —�� �� silt content of Che till soils, the subgrade soils will Ue susceptible to <br /> �� disturbance if allowed to hecome wet. It may be necessary to pour a lean � <br /> I : concrete "mud maL'" or place a layer of crushed rock in Clie Uottom of Clie j <br /> � foo[in�s Co protect the footing subgrnde from disturbance if footings are <br /> constructed durin� wet weatiter. �� <br /> Iw � � <br /> ', <br /> � . <br /> i _.__ <br /> ��,.-•,.----� .�.. , _._._. _ <br /> _ _ <br /> �,:x�� . .-:.� . .. R�l"S+a��.. r 7?'��_v=t.�eo;,--:�. � � . ;:� '. <br /> .. " . . . - . .. . � . .. . " . . � . . . . .1� � . . <br /> I <br />