832 RUCKER AVE 2016-01-01 MF Import

� Proposed Modification to the Residence of Joel & Kathy Larsen ORA Project Number: 04-0 5 Report 1 Everetl, Washington fSILT or CLAY soils, which is what is encountered at depth at this site. In addition, the Ilimited head space and site access eliminated augercast piles as a viable alternative. I Driven piles develop their load carrying capacity from a combination of friction along the side of the pile and from end bearing. Driven piles are best suited when weak, I compressible, cohesive, or non-cohesive soils overlie strong, relatively incompressible soils. These condE'ions exist at this site, therefore, we recomm .nd that galvanized, two- inch diameter, Schedule 80, pipe (pin) piles be used to support the primary, residence � building on this site. They can be driven in relatively short sections with a 90-pound pneumatic hammer. Short sections can be driven and coupled together to acf ieve the � necessary length. Pin piles should also be used to support the garage buildings. These piles could be driven in longer sections with larger, vehicle-mounted equipment for more . efficiency. We estimate that two-inch diameter, Schedule 80, steel pipe piles will achieve a load carrying capacity of about 4 kips per pile if driven to refusal at an estimated tip elevation of 487 feet. Refusal is defined as less than one-inch penetration in 40 seconds of continuous driving. A contractor experienced in the installation of pin piles should be employed to install the pin pile foundations If larger diameter, larger capacity piles are used to support the building they should be installed by a contractor specializing in the installation of pin and/or pipe piles, using hammers of sufficient energy to drive the piles to refusal. Nominal three-inch diameter, Schedule 40, galvanized steel piles should achieve �i load carrying capacity of about 10 kips per pile if driven to refusal with a 650 pound hydraulic hammer. Refusal is defined as less than one-inch penetration in 25 seconds of continuous driving. Nominal four-inch diameter, Schedule 40, galvanized steel piles should achieve a load carrying capacity of about 20 kips per pile if driven to refusal with an 850 pound hyc+raulic hammer. Refusal is defined as less than one-inch penetration in 16 seconds of continuous driving. The actual load carrying capacity of any size pin pile used on this project must be determined by testing at least one pile of each size to at least two times the design capacity. We estimate the bottom of the grade beam will be at elevation 497 feet, therefore, the maximum length of unsupported pile will be about five feet during liquefaction of the Otto Rosenau 8 Associates, Inc. Page 6 ot 13