3210 36TH PL NE 2018-01-02 MF Import

Clcaring and Grubbing ivlost of the site is vegetated with grassc5 �nd shrubs. "fhe surticial soils at the site include thin topsoil deposits and till soils. Pill esists in the areas of old swctures in :he northem portion of the site and along i thc old access rcad that traverses northeast-southwest through tnc site. In locations whem fill will be placed that is b�rcater than 2 feet thick bclow the tinal site subgrade elevation, we recommend that vegetation be mowed as close as practical to the ground sarface and that the cut vegetation be removed Crom the site prior to placing fill to raise site grades. �Vhere fill is Icss th�n 2 feet thick bclow pavemenddrivcway section suUgrade, we recommend that the topsoil and organu materials be completely stripped mid removed from the pavement areas. r111 existing shrubs and trees should be rcmoved for [he fill arcas. Trees should be cut Flush �vith thc ground surface, ifcovcred with ut Icast 3 tcet of fill; otlicr�cisc die ro�it balls should be remoc'ed. Subgrade Preparation The exposed subbRade in structurc mid pavcm�nt arcas should be evaluated after site clearing and stripping is complcte and prior to till placcmcnt. ProoGrolling with hea�y, rubber-tired construction cyuipntent should be used for this purpose during dry a�ezther. Probing should be used to evaluatc the suUgrade during periods of wet wcadier. Saft areas noted during proofralling or probing should bc excavatcd anc'. replaccd with compacted s[ructural fill. Evuluating subgrade conditions at the �i.e iu planned structure and pavement areas will be extremely important �nd will likely rcquire much judgment based on thc conditions observed and the planned improvement. Water and organics should be removed Gom all ditches prior to being fil(ed. Fill pfaced in ditches shuuld be plxed and compacted as structural fdl to reduce potential diFfcrential settlements under future sVuctures. We recommcnd that a gcotextile separation fabric (such as TC Mirafi 600X) be placed over nati��e subgrade soils in all swcwral areas, including planned pavement sections. The geotextile separator will Iallow the granular fill soils to remain cican throughout construction and thereby maintain the necessary support for the strucwres and pavement areas. In addition, the ncparator ��ill provide a better «�orkin, surface and support o�•cr Qie soft ground for the contractors' equipment once o��erlain by structural hll. The geotextile may be placed direcdy on the native ground surface. The eeotcxtile should be placed such that there are no folds or wrinkles :md the material is pulled taut. Adjacent geotextile panels should Ue overlapped a minimum of 2 fect. The first loose lift of fill placed over die geotextile should be l2 w 13 inches thick and spread unilornily �vith a dozer. Lyuipment should not be routed directly on thc geotextilc or when diere is Iess than 12 inches of cover. In addition, rubber-tired equipment should not bc ailowed ovcr the geotextile unless there is at lcast 2�t inches of cover. Due to the anticipated soft b�round conditions the geotextile may be dama�ed �vithout adequate protection during construction. Structural Fill Materials Materials placed as fi!l to raise sitc er:,des in thc ��iciniry of proposed aggregate stockpiles, structures, pavement areas, or other improcemcnts are classitied as structural fill. Structural fill material quality varies depending upon its use. Ctructural till placed to raise site grades should meet the critena for common borrow, �VSDOT Standard Specification 4 03.14(3). Common borrow �vill be suitable for use as struc[ural fill during dry weather canditions or,ly. [f strucwral till is placed dunng �vet weather, the structural fill shoi�ld consist of b�avel borrow as described in Section 9-03.14(1) with the exception that die percent passing the U.S. No. 200 Sieve should be less than 5 percent. Common borrow should not Ue planned as structural fill dunng the Fifch'n.8987-OOJ-UO Pabe 7 �iEOENGINEER� Oc�oGcr 1!,2�06