3928 FRIDAY AVE 2024-10-24 - Laserfiche WebLink

I of 5 LONGITUDE ONE TWENTYO ENGINEERING&DESIGN Pile Review for Structural Compliance Date: May 22nd, 2024 Project Name: Foundation Stabilization/Lift — Everett Project Number: S240104-1XR Project Location: 3928 Friday 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 re- quirements specified in the L120 Structural Calculation Package and Structural Site Plan dated March 41n 2024. During the week of May 21st, 2024, ten (10) helical piles were installed by R&R Foundation Specialists (R&R) to stabilize areas of the single-family residence located at 3928 Friday Ave, Everett, WA 98201. 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 on May 21st 2024 during the pile installation. The helical piles were installed with maximum pile spacing of 6'-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 200'.%MIN VERTICAL PILE# PILETYPE LOCATION BTWN PILES END OFFSET ALLOWABLE LOADING CAPACITY (MIN ULTIMATE CAPACITY) 1 2 15.0 k/PILE 30.0 k/PILE GARAGE 1,8-10 HELICAL G' U" PFR PLAN 9.0k/PILE 18.0k/PILE EXT/INT 4-7 1 1 12.0 k/PILE 24.0 k/PILE EXT/INT 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.