Thomco Construction Inc. 6/14/2021

' KRAZAN&ASSOCIATES, INC. KA Project No. 092-20006 DRAFT Geotechnical Engineering Investigation Everett Water Main"V" May 7,2020 Page No. 11 1 Project Area 3 Table 3: Seismic Design Parameters (Reference: 2015 IBC Section 1613.3.2,ASCE,and ATC) Seismic Item Value Site Coefficient Fa 1 Ss 1.266 SMs 1.266 SDS 0.844 Site Coefficient F, 1.518 S 1 0.482 SM1 0.732 SDI 0.488 Additional seismic considerations include liquefaction potential and amplification of ground motion by soft soil deposits. The liquefaction potential is highest for loose sand with a high groundwater table. The medium dense to very dense native soils interpreted to underlie the site are considered to have a low potential for liquefaction and amplification of ground motion. CORROSION POTENTIAL Information regarding the corrosion potential of soils is presented in a manual prepared by the California Department of Transportation (Caltrans) — Division of Engineering Services — Materials Engineering and Testing Services — Corrosion Technology Branch titled, "Corrosion Guidelines — Version 1.0,"dated September 2003. In general, soils with elevated concentrations of chloride and sulfate, low pH, and low resistivity are considered to be potentially corrosive to metal objects, including metal pipes and structures. The Caltrans guidelines indicate that a site is considered to be corrosive if the chloride concentration is 500 parts per million(ppm) or greater,the sulfate concentration is 2,000 ppm or greater,the pH is 5.5 or less, or the minimum resistivity value is less than 1,000 ohm-cm. Only one of these conditions needs to exist for the soil to be considered potentially corrosive. Laboratory tests were performed on soil samples collected from the project site. Test results are presented in the tables below. The Standard Penetration Test sampling method does not provide a large Krazan&Associates,Inc. Offices Serving The Western United States