2118 JEFFERSON PL 2024-10-25 - Laserfiche WebLink

I of 6 LONGITUDE ONE TWENTYO ENGINEERING&DESIGN Pile Review for Structural Compliance Date: February 20th, 2024 Project Name: Foundation Stabilization/Lift — Everett Project Number: 5230503-2XR Project Location: 2118 Jefferson Pl, Everett, WA 98203 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 August 291h 2023. During the week of January 10th, 2024, nine (9) helical piles were installed by R&R Foundation Specialists (R&R) to stabilize areas of the single-family residence located at 2118 Jefferson Pl, Everett, WA 98203. The EOR from L120 Engineering and Design was present on site during the pile installation. To the knowledge of L120, these piles were installed by R&R certified installers in accordance with the cited structural package, ESR-3750. Please refer to the attached drive log and photographs provided by R&R. The helical 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) 1-2,5 8'-0" 5.0 k/PILE 10.0 k/PILE GARAGE 3-4 HELICAL 8'-0, PER PLAN 7.0 k/PILE 14.0 k/PILE GARAGE 6-7 7'-0" 11.0 k/PILE 22.0 k/PILE EXTERIOR 8-9 8'-0" 10.0 k/PILE 20.0 k/PILE GARAGE Pile capacities for the helical piles have been calculated using a Digga HH-6K 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 1,000 psi results in a maximum allowable capacity of 14.0 kips including a safety factor of 2.