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HomeMy WebLinkAboutMiscellaneous Field Test & Inspection Report 2010-8-16 -a E'nginE'E'ring K & A Engineering, Inc. 91051 S. Willamelte Street P. O. Box 8486, COburg, OR 97408 (541) 684-9399 Voice (541) 684-9358 FAX kaengineers.com August 16, 2010 Project: GDL1 001 GDL Construction P.O. Box 8788 Portland, OR 97207 Subject: Foundation pad construction Springfield permit COM-201 0-00952 6086 Graystone Loop PURPOSE AND SCOPE As requested, K & A Engineering, Inc. has made a geotechnical evaluation of the foundation soils exposed during construction of a foundation pad for the proposed new single-family residence to be constructed at the subject project site. The purpose of our evaluation was to determine the suitability of the site for the proposed new foundation and to make on-site recommendations for foundation pad construction. The scope of our services included several site visits during foundation pad construction, in-place density testing of fiils, and this report. FOUNDATION PAD General Site Conditions The project site is a residential lot located on the north side of the street. This had been modified during construction for the subdivision by the piacement of coarse basalt "pit-run" structural fill to form a level bench. The ground surface on this iot originaily sloped facing the west. After placement of the fill the buildable are of the lot was essentiaily level. Prior to the final modifications to the foundation pad for this project vegetation on the foundation are consisted of light grasses. We observed no indications on the ground surface of slope movement. General Subsurface Soil Conditions Subsurface soils in the foundation pad area consisted of coarse basalt "pit-run" fill. We did not observe placement of the fiil or preparation of the subgrade on which the fill was placed. Our understanding is that this fiil was approved by others as part of acceptance of subdivision improvements by the City of Springfield. Construction Final preparation of the site for construction of a new foundation system included stripping the surface of grassy organics and placement of approximately 6 to over 12-inches of fine select granular fill consisting of %-inch weil-graded crushed aggregate. K & A Engineering, Inc. We tested the in-place dry density of the select granular fill, as placed, and have determined that the average in- place dry density exceeds 95% of maximum as determined by ASTM 0698. A copy of the test results is attached to this report. SUMMARY AND RECOMMENDATIONS General Suitability It is our understanding that the coarse basalt "pit-run" fill placed as part of subdivision improvements was inspected and approved by others and that the fill was accepted by the City of Springfield. K & A Engineering, Inc. has no responsibility for this fill. Recent improvements made to prepare the site for foundation construction, including stripping of vegetation and construction of fine select granular fill (as described above) is suitable to support the proposed new single- family residence supported by a conventional cast-in-place concrete spread footing foundation. If the previously-placed coarse basalt "pit-run" fill was placed properly on a subgrade that was properly prepared, the foundation pad is suitable to support the proposed foundation. We recommend acceptance of the fine select granular fill, as constructed, by the local building official. LIMITATIONS OF THIS REPORT This report has been prepared for the exclusive use of GOL Construction and for the subject proposed structure. This geotechnical investigation, analysis, and recommendations meet the standards of care of competent geotechnical engineers providing similar services at the time these services were provided. We do not warrant or guarantee site surface or subsurface conditions. The bench constructed previously of coarse basalt "pit- run" was made by others without our inspection or approval and we have no responsibility for this fill. The scope of our services does not include construction safety precautions, techniques, sequences, or procedures, except as specifically recommended in this report. Our services should not be interpreted as an environmental assessment of site conditions. Thank you for the opportunity to be of service. Please call us if you have questions or need further assistance. Sincerely, ElO'IRES _ 12/31/2010 Michael Remboldt, P.E., G.E. K & A Engineering, Inc. Project: GOL 1001 Client: GOL Construction 6086 Graystone Lp., Eugene, OR Page 2 of 2 August 16, 2010 . .. . Density of Soil and SOil-Aggregates In-Place ASTM 02922 and 03017 Project: GDl1001 Site Address: lot 9 Mountaingate West Permit No: Date: 8/30/2010 Density Test Type': DT-8" Operator: CCD Material Type: 3/4-inch minus, dense graded crushed agg., Springfield Quarry Maximum Dry Denstiy, pel 141.0 Standardization and Reference Check !J. Density I If Moisture, I (Standard Deviations (S.D.) 0.22 (S.D:) 0.77 Moist Dry Density, Density, Water Compaction, Test No. pel pel Content, % % Remarks 1 143.4 136.1 5.4 96.5% 2 144.3 137.7 4.7 97.7% 3 146.9 139.3 5.5 98.8% 4 153.7 145.5 5.6 103.2% Average: 99.0% Std. Dev.: 2.92% 1 Direct Transmission (DT) (specify depth, in.) or Air Gap Backscatter (AGB) (specifiy(T)ouchable or (U)ntouchable mode Tesf pertormed using Seaman Nuclear Corp model C-300, SN 21113 Client: GDl Construction, Inc. Project: GDL1 001 K & A Engineering, Inc. 8/3/2010