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NG A� <br />Main Office <br />17311 —135' Avenue NE, A•500 <br />Woodinville, WA 98072 <br />(425) 486-1669 FAX (425) 481-2510 <br />(425) 337.1669 Snohomish County <br />April 24, 2013 <br />Mr. Logan Fox <br />46261larbor Lane <br />Everett, Washington 98203 <br />NELSON GEOTECHNICAL <br />ASSOCIATES, INC. <br />GEOTECHNICAL ENGINEERS & GEOLOGISTS <br />Construction Monitoring Summary Letter <br />FOx RCSIdC11CC Underpinning and Retaining Wall <br />Everett, Washington <br />NGA File No. 8592B13 <br />Engineering -Geology Branch <br />437 East Ponny Road <br />Wonalchee, WA 98801 <br />(509) 665.7696 FAX (509) 665.7692 <br />PW /:?I!- Vc-L <br />Dear Mr. Pox: <br />This letter summarizes our gcotcelmical construction monitoring services for your residence foundation <br />underpinning and Ultm-Block retaining wall construction at your property located at 4626 Harbor Lane in <br />Everett, Washington. We have previously prepared a gcoteclmical engineering evaluation for this project <br />titled "Fox Residence Underpinning and Retaining Wall Design," dated August 3, 2012. We were <br />retained to provide part-time monitoring and consultation services during the construction of the retaining <br />wall and underpinning of the residence foundations. We observed construction activities on a part-time <br />basis from April 3, 2013 through April 17, 2013. Our observations and conclusions were documented in <br />Field Reports I through 8, which have been submitted to you. <br />Our services began by observing pin pile installation for the residence foundation underpinning. We <br />observed the installation of 14, galvanized schedule 80, 2-inch diameter pin piles driven with a 140 pound <br />hatnnler. Tlpe piles were driven to a refusal criterion of less than one -inch of pile movement during 60 <br />seconds of continuous driving. The piles were advanced to between 7.5 and 16 feet below the existing <br />ground surface when refusal was mct. Based on our observations during pile installation, it is our opinion <br />that the pin piles were successfully installer and should provide adequate support for the planned loads. <br />The pin piles were then connected to the residence foundation utilizing contractor manufactured brackets. <br />We understand that the brackets were approved by the structural engineer; however, we are not aware if <br />