1600 MADISON ST 2016-01-01 MF Import

Mr. Chris Lark February 20, 2001 3.3 PRev�ous ExP�o�taTlorvs Several borings were advanced at the site in 1991, as part of a soil contamination study perfortned by others. Summary logs of these borings aze included in Appendix C. 'ihe approximate locations of these borings aze also indicated on Figure 2. 4.0 SUBSURFACE CONDITIONS In general, tt,e site is mantled by a t}un layer of undocumented fill that overlies glacial till. The fill was observed to be typically no more than about 2 to 3 feet thick, except at boring BH-7 where approximately 6 feet of fill was encountered. The thicker layer of fill at Boring BH-7 is attributed to !he fact th«t the boring was drilled in an area of a former underground storage tank (UST), which had been backfilled with loose, clean sand fill. At this location, a clear plastic sheet was encountered at the hase of the fill. In other borings, the existing fill vazied from loose to mediutn dense, silty sand to medium stiff silt. Directly beneath the fill, the observ�cd glacial till consisted of very dense, silty sand and sandy silt with a variable amount of gravels. The till extended to the mazimum depth explored at the site, which was approximately 60 feet at boring location BH-7. In some azeas, the upper 2 to 3 feet of glacial till was weathered and typically consisted of inedium stiff to stiff, sandy silt. Although not observed in the borings, cobbles and boulders should be anticipated in glacial till. _ Soil samples obtained from at depths of45 and 30 feet in borings BH-6 and BH-7, respectively, S appeared to be very moist. Groundwater monitoring wells were installed in both of these boring � to provide information on the groundwater level and also to provide water samples that may be tested to detetmine the potential presence of contaminants in the groundwater. G-Logics, Inc. is I` separately evaluating the presence of potentially cor�tamir.ated soils and groundwater beneath the . site. 5.0 DESIGN RECOMMENDATIONS 'The glacial till stratum that underlies the site provides an excellent bearing stratum allowing the new Fire Station No. 5 to be constructed on shallow spread footing foundations as currently planned. The footings and other project elements should be designed and constructed in accordance with the recommendations discussed below. 5.1 SEISMIC COIVSIDERATtONS Based on the Uniform Building Code (UBC, 1997), the project site is located within Seismic Zone 3. The proposed facility should be designed to resist earthquake loading in accordance with applicable local or state requirements. If the UBC design methodology is used, the glacial till soils that underlie the site should be classified as UBC Soil Type S�. { 00-046-100 Geotech Repon 3 PanGEO, Inc.