4849 SPIRE LN 2023 Geotech Report 2025-10-15

Proposed Remedial Excavation: 4849 Spire Lane, Everett, WA December 8, 2022 3. Piles shall be driven in nominal sections and connected with compression fitted sleeve couplers. We discourage welding of pipe joints, particularly when galvanized pipe is used, as we have frequently observed welds broken during driving. 4. The geotechnical engineer of record or their representative shall provide full time observation of pile installation to verify that the pile has been driven to adequate refusal within the anticipated bearing stratum. The quality of a pin pile foundation is dependent, in part, oil the experience and professionalism of the installation company. We recommend that a company with experienced personnel be selected to install the piles. Estimated Pile Leneth - The required pile length in order to develop the recommended pile capacity is expected to vary somewhat along the length of the footing, depending on the actual driving conditions encountered. We estimate that the pile lengths, on average, may range from 20 to 25 feet below grade. We recommend the pin piles extend a minimum of 5 feet below the bottom of the adjacent excavation. As such, we recommend a minimum embedment depth of about 20 feet below the ground surface. Obstructions - Obstructions may be encountered within the upper fill. Where possible, the obstructions should be removed to facilitate the pile driving. If obstructions cannot be removed, the structural engineer of record should be notified to revise the pile layout to accommodate moving the piles. Pile Connection — The project structural engineer should provide details to connect the driven pipe pile to the existing foundation. In our experience, we have observed successful projects that have utilized L-brackets that attached to the underside of the footing. EXCAVATION & TEMPORARY SNORING We understand that the proposed remedial excavation will extend about 15 feet below the existing ground surface. We expect the excavation to generally encounter from 4 to 8 feet of loose to medium dense sand over dense to very dense sand. Because we understand that some of the excavated soils may be environmentally impacted, we recommend that the handling, storage, and disposal of the environmentally impacted 22-389_4849 shire lane everett ipt.docx Rage 7 PanGEO, Inc.