1600 MADISON ST 2016-01-01 MF Import

'J � � I� � ; Mr. Cliris Lark February 20, 2001 3.3 PREVIOUS EXPLORATIONS Several borings �vere advanced at the site in 1991, as part of a soil contamination study performed by others. Summary logs of these borings are included in Appendix C. The approximate locations of these borings are also indicated on Figure 2. 4.0 SUBSURFACE CONDI'fIONS In general, the sile is mantled by a thin layer of undocumented fill that overlies glacial till. Thc fill was observed to be typically no more than aboul 2 to 3 feet thick, except at borin� BH-7 where approximatcly 6 feet of fill was encountercd. The thicker layer of fill at Boring BH-7 is attriUuted to the �act that the boring was drillcd in an arca of a former undergruund storage tank (UST), which had becn backfilled with loose, clean sand fi'l. At this locatio�:, a clear plastic sheet was encountered at the base of the filL In other borings, the cxistiog (ill v:u�icd from loo:;e to medium dense, silty sand to medium stiff silt. ' DirecUy beneath the fill, the obscrved glacial till consisted of vciy dcnsc, silty s�ind and sundy i " silt witlt a variable amount of gravels. The till extended to thc maximum dcpQi cxplorcd al dic i site, which was approximately 60 feet at boring focation BH-7. In some areas, lhe upper 2 to 3 '� fect oF�lacial tilf was weathered 1nd typically consisted of inedium stiff to stiff, sandy silt. � Althc�ugh not observed in the Uorings, coUbles and houlders should be anticipated in glacial till. Soil samples obtained from at deplhs of 45 and 30 feet in borings BH-6 and BI-I-7, respectively, appeared to be very moist. Grow�dwater monitoring �vells were installed in both of these boring to provide information on the groundwater level and also to provide water samples ihat may be tested to determine the potential presence of contaminants in the ground�vater. G-Logics, Inc. is sepazately evaluating the presence of potentially conta�ninated soils and groundwater bencath the site. 5.0 DESIGN RGCOMMENDATIONS The glacial till ctratum tl�at underlics tlte site provides an excellent bearing stratum allowing the new Fire Station No. 5 to be constmcted on shallow spread footing foundations as cunently planned. The footings and other project elements should be designed and constructed in accordancc with the recommendations discussed below. 5.1 SE�sm�c Corrs�neanT�orvs Based on the Uniform Building Code (UBC, 1997), lhe project site is located witliin Seismic Zone 3. The proposed facility should be designed ro resist carihquake loading in accordance �vith applicable local or state requirements. ICthc UBC design methodology is used, tlie glacial till soils that �nderlie the site should be classified as UBC Soil 1'ype S�. 00-046-100 Geotech Report 3 PanGEO, Inc. �6