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HomeMy WebLinkAbout20180398E003_Renton_ES_16_2022-09-30_FR_067 Kirkland | Tacoma | Mount Vernon 425-827-7701| www.aesgeo.com Date Mailed: Principal / PM: Bruce Guenzler, L.G., L.E.G. This document is considered a DRAFT until signed or initialed by an AESI Principal or Project Manager Page 1 of 3 v.7.20 FIELD REPORT Date Project Name Project No. Report No. 09/30/2022 Renton Elementary School 16 20180398E003 067 Location Municipality AESI Project Manager AESI Field Rep 1075 Duvall Ave NE Renton Bruce Guenzler, L.E.G. Bruce Guenzler Permit No. Client/Owner Attn Requested By B21004604 Renton School District No. 403 Ed Thomson Contractor Engineer/Architect General Contractor Grading Contractor Weather CPL / Hutteball + Oremus Cornerstone/Kyle Continental Dirt Contractors/ Jerry Jr. Sunny, 80’s THE FOLLOWING WAS NOTED: Associated Earth Sciences Inc. (AESI) was on-site in the morning to observe installation of a low permeability barrier between the quarry spall underdrain installed in June and Storm Water Detention Facility 2. Stormwater Detention Facility 2 After a site meeting on Monday, AESI and LPD prepared recommendations for installation of a low permeability barrier between the quarry spall underdrain installed in June and Storm Water Detention Facility 2. The quarry spall underdrain was constructed in June to intercept seepage that was causing constructability challenges for earthwork. The quarry spall drain served the intended purpose in June but is now dry. The approximate drain location is shown on the sketch below. The approximate depth below existing grade of the quarry spall drain is 5 to 6 feet. Storm Water Detention Facility 2 consists of an array of open – bottomed Stormtech arches sitting on top of a gravel bearing pad and covered by compacted structural fill. The facility includes an impermeable plastic liner below the gravel bearing pad. The purpose of the low permeability barrier is to disconnect the quarry spall drain from Storm Water Detention Facility 2 so that any groundwater seepage collected by the quarry spall drain is not directed into the gravel bearing pad or below the liner of Storm Water Detention Facility 2. The low permeability barrier was constructed by cutting a swath across the quarry spall drain from east to west and penetrating at least one foot beyond the limits of the quarry spall drain laterally and vertically. Total excavation dimensions were 10 by 30 feet in plan view and 7 feet deep (77 bank cubic yards). Photos of the finished excavation are included below. Excavated material consisted of dense well compacted fill composed of previously excavated on site lodgement till. The quarry spall layer was covered in nonwoven filter fabric and was approximately one foot thick in the area of the excavation. The excavation was backfilled with compacted on site lodgement till estimated at 0-2 percent over optimum moisture content placed with a 50 ton roller, hoepack, excavator and small dozer. No nuclear densometer was available on site. The fill placement was observed during installation with a hand probe, which typically allowed approximately one half inch of penetration. The fill placed in the excavation is anticipated to perform well as a low permeability barrier between the remaining section of quarry spall underdrain and Storm Water Detention Facility 2 and will also provide adequate support for paving and landscaping in our opinion. A small section at the corner of Storm Water Detention Facility 2 adjacent to the low permeability barrier had not been previously completed to assist planning of the low permeability barrier. The incomplete area was backfilled at the same time as the barrier installation and was firm and unyielding and suitable for support of planned paving and play areas in our opinion. 16 Date Project Name Project No. Report No. 09/30/2022 Renton ES 16 20180398E003 067 Page 2 of 3 FIELD REPORT Photo of low permeability barrier excavation, south sidewall. 16 Date Project Name Project No. Report No. 09/30/2022 Renton ES 16 20180398E003 067 Page 3 of 3 FIELD REPORT Photo from east looking west with low permeability barrier dimensions.