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Home My WebLink AboutObservation of Excavation 09.27.2018H-PKUMAR Geotechnlcal Engineering 1 Engineering Geology Materials Testing 1 Environmental 5020 County Road 154 Glenwood Springs, CO 81601 Phone: (970) 945-7988 Fax: (970) 945-8454 Email: hpkglenwood@kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, Summit County, Colorado September 27, 2018 Jeff Powers 12091 County Road 320 Rifle, Colorado 81650 jeft'andaepowers @ gmail.corn Project No. 18-7-349.A Subject: Observation of Excavation, Proposed Residence, Lot 7, Gilead Gardens, Harvest Lane, Garfield County, Colorado Dear Mr. Powers: As requested by Miles Rippy, a representative of H-P/Kumar observed the excavation at the subject site on September 19 and 24, 2018 to evaluate the soils exposed for foundation support. The findings of our observations and recommendations for the foundation design are presented in this report. We previously provided an addendum to a subsoil study for design of foundations at the site and presented our findings in a report dated May 21, 2018, Project No. 18-7-349. The residence has been designed to be supported on spread footings placed on the natural soils or on compacted structural fill sized for an allowable bearing pressure of 1,500 psf. At the time of our initial visit to the site, the foundation excavation had been cut in one level from 3 to 6 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted of silty sandy gravel and cobbles. We understand the footing areas had been sub -excavated through the clay soils to expose the river gravel deposit. No free water was encountered in the excavation and the soils were slightly moist. We returned to the site on September 24 to take in-place density tests for evaluation of the structural backfill compaction. The test results, presented in the attached field density report, indicate adequate compaction of the backfill was achieved. The gravel soils exposed in the excavation and compacted structural fill are consistent with the previous foundation bearing recommendations and suitable for support of spread footings designed for the recommended allowable bearing pressure of 1,500 psf. Loose disturbed soils in the footing areas should be removed or compacted prior to concrete placement. Other recommendations presented in our previous report which are applicable should also be observed. The recommendations submitted in this letter are hase,1 nn niir nilePrTrat r,n of ti,' .,-s 1.. ,... �.., Jeff Powers September 27, 2018 Page 2 conditions for possible changes to recommendations contained in this letter. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in the future. If the client is concerned about MOBC, then a professional in this special field of practice should be consulted. If you have any questions or need further assistance, please call our office. Sincerely, H -P t KU MAIC Steven L. Pawlak, 16-222 -71)54 SLP/kac■.■� r ..■�� 9 QP t` Attachment: Earthwork a"::' on Testing Report: 9/24/18 H-PMKUMAR Project No. 18-7-349.A H-P;KUMAR Geotechnical Fnrnneering Engineering Geology fviateri ,ls Testing ; Eirvirc rnentai Office Locations: 5020 County Road 154 Glenwood Springs, CO 81601 Phone: (970) 945-7988 Fax: (970) 945-8454 Email: tipkcflenwood a7Ecumarusa cvm Parker, Glenwood Springs, and Silverthorne, Colorado Earthwork Compaction Testing Report Client: Jeff Powers 12091 County Road 320 Rifle, Colorado 81650 Project No.: 18-7-349.A Day: Date: Page: Monday 9/24/18 1 of 1 Project: Proposed Residence, Lot 7, Gilead Gardens, Harvest Lane, Garfield County, Colorado Weather: Cloudy, calm, dry Temperature: 70° at 1:00 pm Earthwork Contractor: Equipment Used: Description of Earthwork Tested: Verbal Communication: Miles Rippy trackhoe, vibratory double drum roller The contractor has completed under footing backfill operations. Compaction was judged to be adequate based on our test results and an estimated Proctor value. no one onsite Placement and Compaction Procedure: Not observed by H-P/Kumar Lift Thickness: Compactor(s) Used: Max. Rock Size: Test No. Location Moisture Conditioning: Number of Passes: Nuclear Gauge Moisture/Density Test Results under footing backfill Depth or Elev. Field Dry Density (Pcf) Field Moisture Content Field Comp. (%) 1 southwest corner footing grade 134.2 4.6 99 Min. Comp. Req. (%) 98 Proctor Lab No. estimate 2 20' east of northwest corner footing grade 133.7 4.4 98 98 estimate 3 40' south of northeast corner footing grade 134.5 4.7 99 98 estimate Proctor Sample Reference: Lab No. Method Estimate ASTM D 698 Description %" aggregate base course Max. Dry Dens. (pcf) 136.0 Opt. Moist. (%) 7.0 THIS REPORT PRESEN1 S OPINIONS AS A RESULT OF OUR OBSERVATIONSOF FILL PLACEMENT_ WE HAVE RELIED ON THE CONTRACTOR TO CONTINUE APPLYING THE RECOMMENDED COMPACTIVE EFFORT AND MOISTURE TO FILL DURING THE TIMES WHEN OUR OBSERVER IS NOT OBSERVING OPERATIONS THE NUCLEAR DENSOMETER METHOD OF TESTING WAS USED IN SUBSTANTIAL ACCORDANCE WITH ASTM D 6936 Distribution: LeffaRif9 *apo.vers(r+J ll1aII.Cillii /kac Philip Orgill Steven L. Pawlak, P.E. Field Technician Reviewed By