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662 CROMWELL AVENUE <br />ST. PAUL. MN 55114 <br />PHONE 612/645-3601 <br />SQlUBSERVAnCN$.aiILlESTlll5 <br />LABORATORY No. 4220 89>464 <br />December 22* 1968 <br />2 <br />one»ha1f stcries above the existing grade. The addition xill be 19* wide by 24' long <br />with a floor slab elevation matching the existing slab elevation of the lower floor of <br />the existing house. The addition will be supported on e perin«ter strip footing <br />approximately 2* in width. We have not been provided with the soil bearing pressures <br />from the proposed project* but we assume they will be on the order of 150C to 2000 psf. <br />Tc our knowledge* no deep soil test borings were performed for this project. <br />Accordingly* we cannot comment on the soil conditions beneath the depths of our shallow <br />hand auger borings. <br />CBSEWATION ICTWODS AMD RESULTS <br />On November 10* 1988* we visited the site at the contractors request to review the soils <br />exposed in the perimeter footing trench excavations. Our observation methods included <br />observing the sides of the excavation* placing shallow hand auger borings within the <br />exposed excavation bottoms and classifying the retrieved soils according to ASTN:D2488. <br />In addition* estimates were made of the strength properties of the retrieved soils. <br />In the majority of the footing excavations* the surficial topsoil and any soft fill soils <br />appeared to have been adequately removed. The soils exposed at planned bottom of footing <br />elevation typically consisted of stiff sandy lean clay* or medium dense clayey sand and <br />silty sand. We also observed that the perimeter footing excavaticr. matched the bottom of <br />the existing building at the southeast addition corner and was approximately 2' below the <br />existing footing elevation at the southwest building corner. The soils observed in the <br />excavations appeared to be naturally occurring glacial till* and were judged suitable for <br />support of assumed loadings of 1500 to 2000 psf. <br />The exception to the above noted soil conditions occurred at two locations. A1 a point <br />approximately 8* west of the southeast corner of the addition* the footing line <br />intersected the existing sanitary sewer pipe for the residence. We recommended that <br />approximately 2' of additional excavation be performed in this area to allow the new <br />footing to step under the existing sewer pipe. Based on our hand auger borings* it <br />appeared that soils exposed at the bottom of this additional 2* cut would be suitable <br />naturally cccurring soils similar to the majority of the footing areas. At a point near <br />•liie southwest corner of the proposed addition area* the footing trench again intersected <br />the fill soils from an existing utility line in this area. This previous trench appeared <br />to be approximately 1' wide and 2' to 3* deep. In this area* the contractor elected to <br />construct a small grade beam to span over the existing utility trench fill soils and <br />allow the footing loads in this area to be carried by the more competent natural soils <br />encountered on either side of the trench. It appeared that the natural soils on either <br />side of the trench would be suitable for support of the additicnal loads transmitted from <br />the grade beam to the foundation elements. <br />CATWMf <br />enow TOC ILVM»AU*C <br />Anew OP or ATOMOWTO* c <br />ITMA CONI <br />POOTOlOP <br />ATVOPeUPNTO.