1612 ROCKEFELLER AVE 2025-04-17 - Laserfiche WebLink

I of 9 LONGITUDE ONE TWENTYO ENGINEERING&DESIGN Pile Review for Structural Compliance Date: November 161h, 2023 Project Name: Foundation Stabilization/Lift — Everett Project Number: S220725-3XR Project Location: 1612 Rockefeller Ave, Everett, WA 98201 Client's Name: R&R Foundation Specialist, LLC To Whom It May Concern: The purpose of this letter is to confirm pile installation and capacity compliance with the structural require- ments specified in the L120 Structural Calculation Package and Structural Site Plan dated September 22"d 2022. During the week of April 261h, 2023,fourteen (14) helical and three (3) concentric piles were installed by R&R Foundation Specialists (R&R) to stabilize areas of the single-family residence located at 1612 Rockefeller Ave, Everett, WA 98201. Please note during construction, one (1) additional concentric pile was added between helical pile #9 and concentric pile #2. To the knowledge of L120, these piles were installed by R&R certified installers in accordance with the cited structural package, ESR-3750 and ESR-4121. Please refer to the attached drive log and photographs provided by R&R. The helical and concentric piles were installed with maximum pile spacing of 8'-0"on-center, the typical minimum required vertical capacity as determined by L120 is shown in the table below. These demand requirements are as determined and specified in L120's structural calculation package cited above. PILE SPACING&LOAD REQUIREMENTS TABLE MAX O.C.SPACING,ft MIN VERTICAL CAPACITY,kips PROOF TESTING LOAD,kips PILE# PILE TYPE 200%MIN VERTICAL CAPACITY LOCATION BTWN PILES END OFFSET ALLOWABLE LOADING (MIN ULTIMATE CAPACITY) 1,4 8'-0" 23.0 k/PILE 46.0 k/PILE CHIMNEY 2-3 PER PLAN 21.0 k/PILE 42.0 k/PILE CHIMNEY "10 8-4-HELICAL 8'-0" 13.0 k/PILE 26.0 k/PILE EXTERIOR 6 88 8' " PER PLAN 8.0 k/PILE 16.0 k/PILE EXTERIOR 9 8'-0" 10.0 k/PILE 20.0 k/PILE EXTERIOR 11-14 6'-0" 10.0 k/PILE 20.0 k/PILE EXTERIOR 1-2 1CONCENTRIC, 8'4" 13.0 k/PILE 26.0 k/PILE EXTERIOR Pile capacities for the helical piles have been calculated using a Digga MM-10K drive head with a torque correlation factor, Kt, of 9 as prescribed in ESR-3750. A chart showing the resulting capacities is attached to this letter. Per the attached document, an Ideal Foundation Systems 2-7/8" diameter helical pile installed to a minimum pressure of 1,100 psi results in a maximum allowable capacity of 17.2 kips including a safety factor of 2.