9 First American Way - Soils Report

Home Browse Search

Luizki Associates Development. LP - Geotechnical Investigalion MACTEC Project 4953-03-2631 Sepiember 18,2003 SUMMARY We have completed our geotechnical investigation for the proposed Data Center to be constructed near Columbine Avenue and Halladay Street in Santa Ana, Cali fornia. The location of the site is shown on Figure 1, Vicinity Map. The locations of the proposed Data Center, existing buildings, and our current and prior explorations are shown on Figure 2.1 Plot Plan and on Figure 2.2, Boring and CPT Location Plan. Our subsurface explorations, engineering analyses, and foundation design recommendations are summarized below. The First American Corporation plans to build a base-isolated, two-story Data Center. The footprint dimension of the proposed Data Center is about 23,000 square feet. We understand that thefoundationwillbeestabl. helat-ElexatiQUALand the finish floor of the proposed Data Center w,iLLkÂ£-Â©4aWk!Â£020]Unxatip.n.21, The site of the proposed Data Center was explored by drilling three borings to depths about 60 to 75 feet below existing grade and advancing two Cone Penetration Test (CPT) soundings to a depth of about 75 feet below the existing grade. About 3 to 8 feet of fill was encountered in our borings at the site of the proposed Data Center. The fills soils consist of iaadugith<Fill's.t49'inaria.gy'"la Deeper fill soils could be present in other locations. The natural soils encountered beneath the proposed Data Center consist of medium stiffto very stiff silty clay and sandy silt, medium dense to dense poorly graded sand, poorly graded sand with silt, and silty sand. Ground water was encountered at depths of!343Â»lfilzebhÂ£lmubukling-Srads. The results of our liquefaction analysis indicate that the medium dense sand layers at depths 0Â£25- 12.itf=1=MINL-e.ng,gade have some potential to liquefy during the Design Basis Earthquake (DBE). Liquefaction-induced settlement is expected to be on the order of'/2 to A inch. during the DBE. Based on the available geologic data, active or potentially active faults with the potential for surface fault rupture are not known to be located beneath or projecting toward the site. In our opinion, the Vi