7423 LOWER RIDGE RD 2024-10-25 - Laserfiche WebLink

I of 6 LONGITUDE ONE TWENTYO ENGINEERING&DESIGN Pile Review for Structural Compliance Date: June 30th, 2024 Project Name: Foundation Stabilization/Lift — Everett Project Number: S240102-1XR Project Location: 7423 Lower Ridge Rd, 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 re- quirements specified in the L120 Structural Calculation Package and Structural Site Plan dated March 51h 2024. During the week of May 301h, 2024, eleven (11) helical piles were installed by R&R Foundation Specialists (R&R) to stabilize areas of the single-family residence located at 7423 Lower Ridge Rd, Everett, WA 98203. 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 FOR from L120 Engineering and Design was present on site during the pile installation. The helical piles were installed with maximum pile spacing of 7'-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 REQUIRMENTS TABLE MIN O.C.SPACING.ft MIN VERTICAL CAPACITY.kips PROOF TESTING LOAD,kips PILE# PILE TYPE BTVJN END ALLOWABLE LOADING 200%MIN VERTICAL CAPACITY LOCATION PILES OFFSET (MIN ULTIMATE CAPACITY) 1-11 HELICAL T-0' 3'-0' 8.0 kip 16.0 kip PER PLAN 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 600 psi results in a maximum allowable capacity of 8.4 kips including a safety factor of 2.