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HomeMy WebLinkAboutSpecial Inspection Field Test & Inspection Report 2000-5-11 -j 0;;7 ( S , OREGON " GEOTbCHNICAL "- '" " SERVICES "- " To: Mr. Eddie McMahon Home Builders Association 1255 Pearl Street Eugene, OR 97401 CC: Rene Fabricant r Branch Engineering 310 N 5th Street Springfield, OR 97477 \ Date: May 11,2000 Re: Construction Insp~tion, Subgrade Verification & Compaction Testing: Home Builders Association Office and Warehouse, 2053 Laura St., Springfield, Oregon. Building Permit# 00-00414-01. The purpose of this letter is to record that on the dates of March 1,3, and 13, and May 8, and 10, 2000, Oregon Geotechnical Services, staff provided inspection of the commercial building construction at 2053 Laura St, Springfield, Oregon, the site of the new Home Builders Association office. This included inspection of the exposed subgrade material in the deep pier footing locations, and inspection and certification of the' fill required to bring the site to grade. This inspection was performed by David E. Reich, Certified Engineering Geologist (OR Lic. # EI227), of Oregon Geotechnical.Services, 38401 Place Road, Fall Creek, Oregon, 97438. Oregon Geotechnical Services staffvisited the site on the dates of March 1,3, and 13, during site preparation, to l-uvvide compaction testing for the structura1 fill placed underneath the building site. Subgrade inspection for the excavations for the deep pier footings was conducted on May 8 and 10 to verify and document sub grade conditions with respect to bearing capacity, shrink swell potential and settlement, and drainage. Field work: included site reconnaissance, visual inspection, and manual testing to verify soil composition as documented during initial site evaluation (see '"Geotechnical Site Evaluation, HOME BUll.DERS ASSOCIATION, Commercial Office and Warehouse, Laura St. and S. Place, Springfield, Oregon" by David E. Reich, dated November 19, 1999), and to confirm ,adequate soil bearing capacity in the slab and footing areas. Iii addition to the soil testing, proof-roll testing was performed in the building area with a fully loaded 10 cubic yard dump truck (gross wt - 50,000 Ibs), to verify the suitability of the subgrade and/or fill, and certify the site as suitable for the proposed building construction. HBACI,SIOO Oregon Geotechnical Services 10f2 38401 Place Road, Fall Creek, Oregon 97438 · Phone/Fax: (541) 937-8747 Testing confirms that the structural fill for the main building pad constructed at the HBA buildilig site is appropriately constructed and adequately compacted Excavation for the fill was a minimum of three feet from original grade and the fill was placed within the brown sandy material of SU-C. Emplacement of gravel pad and footings within this material is in accordance with recommendations }J~vv1ded by OGS in the initial site evaluation report, and should provide an allowable bearing capacity of approximately 2000 PSF (pounds/sq. ft.). A bearing capacity of approximately 2000 PSF can be expected for footings placed directly on the structural fill, based on measurements taken in the location of the proposed structure. Testing confirms that the fill is evenly compacted, and that the density of the fill in,,~(.aSes with depth into the fill. Tests indicate that a minimum relative compaction of 95% (ASTM D 1557) has been achieved in the aggregate fill. Eighteen deep footings have been excavated along the building perimeter to handle isolated loads. Excavation depth for deep footings varied between 5 and 8 feet beneath the existing surface of the gravel pad EXcavation was continued in each hole until dense sandy gravel (SU- G) was encountered All of the deep footings have been placed as recommended, within the dense sandy gravel, and should proVide and allowable bearing capacity of approximately 6000 PSF. Runoff from downspouts and surface drainage should be directed away from the footings and fill to avoid differential settlement of the foundation. The landscaping .and ground surface around the perimeter of the footing should be graded so that the ground surfaces slope away from the foundation. Limitations This report was prepared for the exclusive use of The Home Builders Association and their authorized agents. Professional services were rendered in accordance with generally accepted geotechnical services, and using the degree of care and skill ordinarily exercised under similar circumstances by firms or individuals practicing in similar locations. Analysis, conclusions and recommendations included in this report relate to conditions at the time the services were performed Data was accumulated from overall site reconnaissance and limited subsurface exploration in select locations. In the event that changes in the nature, design or layout of the project are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and verified in writing, and no warranty is expressed or implied HBA CI, 5/00 Oregon Geotechnical Services 20f2 Tfyou have any comments or questions please give us a call at 937-8747. Sincerely, Oregon Geotechnical Services ~~~ David E. Reich, PG, CEG