1424 BROADWAY Geotech Report 2018-01-02 MF Import

I r Gcarechnirnl Er�grnccring R(porr 3 Jm�e?. 1009 Cnmmiinil��Henlrh Cenler. Everel4 {I.1 Prnjec!�1009-1�a I Liquctaction mainly a(f'ects geologically recent deposits of tine-grained sands that are I bclow thc groimdwatcr tablc. Soils of this naturc dcrivc thcir stmngth tiom intcrgranular I�iction. Thc gcncr.�ted water pressure or porc pressurc essentially separates the soil grains and eliminales this intcrgranular friction. Uius reducing or eliminating the soil's strength. Il��e revicwed the soil conditions encoimtered during field exploration and assessed the potcntial 1'or liquefaction oC the site's soil during an �arthquake. Glacial till is generally I considercd not subjzct to liqiicf�ction during an carthquake. Therefore, RGf bclicves that the sitc liqucfaction polential during an carthquakc is minimal. � J.0 DISCUSSION ANU RECOMMENI)ATIONS J.1 Gcncr•rl II3ascd on our study, thc site is suitable 1'or the proposcd dcvclopment liom a gcotechnical standpoinL roundations f'or the proposed building can be supported on com�entional spread I lootings bcaring on mcdium dcnsc to dcnsc native soil or structural fill (if necdcd). Thc slab-on-grade and pa��cment can be similarly supported on tirm soils. Detailed recommendations rcgurding the above issucs and other gcotechnical dcsign Iconsidcrations arc provided in the following scctions. Thcse rccommendatious should be incorporated into the final design drawings and construction spccitications. I �1.2 Sitc Pren:�r:�tion :�nJ GraJine To prcparc thc sitc I'or ncw construction, the esistine buildings and pavcment should bc I demolished and stripped. 3urlace stripping depths of up to 6 inchcs should be expected to remove lhe asphalt surface. All rcmnants rclated to previous construction, which occupicd the site, should bc cicared and removed from tlic sitc. IOnce clearing and other prcparing operations are completa cuts and lills can be madc to eslablisli dcsircd building gradcs. Prior to placing lill, wc rccommcnd proot�olling all exposed surlaces to determine il' any isolatcd loose and yiclding amas arc present. Proolrolling should also be perlormcd in ciU areas that will provide direct support lor new constniction. � 'I'hc on-site eaca��ated soils without organic matcrial are gcnerally suitable for bcing uscd as structunl fill if soil's moislurc can bc properly controllcd. [f Ihc site grading rcquires i additional structural till material. �ve rccommcnd importing a material that mccts thc brading requircmcnts listcd in'I'ablc l. Prior to use, RGI should examine and tcst all mnterials importcd to the site f'or use as slructural fill. Structural lill nmterials should be placed in uniform loose layers not exceeding 12 inchcs and compacted to a minimum oC 9� percent of the soil's maximum density, as determined by AS7'M "I'est Designation D-I>j7 (Modilied Proctor) until the � desircd finishcd grade is met. 'Che moisturc content of the soil at thc time of compaction should bc �vitliin abuut hvo perccnt of its optimum, as dc(crmined by this ASTM mcthod. I The Riley Group, Inc. �