1318 37TH ST Geotech Report 2018-01-02 MF Import

, � • . James Pirie . � JN 97072 . March 19, i997 , Pags 2 overly steep cut slopes along the southwestern side of the lot, at the edge of High Street. These cut slopes are about 10 feet tall and have inclinations of approximately 1:1 (Horizontal: Vertical). We observed no evidence of recent slope instability or significant soil erosion o:; the property at the time of our visits. No groundwater seepage was visible or� the site slopes. fiowever, the low area along 37th Street and Grand Avenue at the northern end of the site ::ontained standing water. Development of the ara,a surrounding fhe site is entirely residential. Single-family homes are situated above the slopes west of Grand Avenue and south of 38th Street. Houses are also Iocated on the mcderate slopes that drop east of the eastern alley. Immediately east of proposed Building 1 are the r�ur,lcer Village Townhome�. This is a recently completed development consisting of six t�.o-story townhouse buildings. The finish floor elevations of the bottom floors of these buildirgs .�ere estimated to be about 310 feet in the southernmost townl�ouse, dropping to about 306 feet in the northernmost townhouse. SuBsurface ' The subsurface co:iditions were explored by excavating seven test pits at the approximate • locations sho�vn on the Site Exploration Plan, Plate 2. The fie!d exploration program was based upori the proposed construction �^d required design criteria, the site topography and access, the subsurface coiiditions revealed during excavation, the scope of work outlined in our proposal, and the time and budget constraints. The test pits w�re excavated on February 20, 1997 with a rubber-tired backhoe. A geotechnical engineer from cur staff observed the excavation process, logged the test pits, and obtained repre�entative samp!es of the soil encountered. "Grab" samples of selected subsu�face soil were collected from the backhoe bucket. The Test Pit Logs are attached to this report as Plates 3 through 6. The test pits generally encountered similar subsurface conditions among the areas that were explored. Six to 12 inches of silty topsoil were found beneath the surface vegeta+ion. Hov.�ever, in Test Pit 3, the topsoil was overlain by about '8 inches of slightly silty, gravelly, sand fill. Beneath the topsoil layer, the test pits �II revealed native, gravelly, silty sand. This native sand became dense within seve�al inches of the topsoii in Test ?its 1, 2, and 7. In the remaining explorations, the native, silty sands were loose to medium-dense far one to 5 feet below the topsoil before becoming dense. Laboratory tests on three selected sarciples of the native, silty sands reveaied in- situ moisture contents of 10.5 to 11.2 percent. The final logs represent our interpretations of the field legs and laboratory tests. The stratification lines on the logs represent the approximate boundaries between soil types at the exploration locations. Th� actual transition between soil types may be gradual, and subsurface conditions can vary between exploration locations. The logs provide specific subsurface intormation only at the locations tested. The relative densities and moisture descriptions indicated on the test pit logs are interpretive descriptions based on the conditions ubserved during excavation. The compaction of backfill was not in the scope of our services. Loose soil will therefore be found in the area of the test pits. If this presents a problern, the backfill will need to be removed and , replaced with structural fill during construction. GEOTFCI I CONSULTANTS,!NC. �� ;%"� i� i" I