1111 80TH ST SW BLDG SHELL 2016-01-01 MF Import

SGA Corporation May 28, 1997 Page 2 We observed the excavation of an sdeiitlonal six test pits across the site on May 20, 1997 The test pits were excavated to depths ranging from about 4 to 7 feet below the existing ground surface. The conditions encountered in the test pits are eompanble to the conditions reported in the previous study. The site is mantled by a surficial layer of forest dufr, topsoil and roots ranging in thickness from about 6 to 18 inches. Glacial till was encountered below the surficlai zone and generally consists of silty sand with gravel. The upper portion of the glacial till is weathered and typically medium dense. The weathered glacial till grades into fresh glacial till at depths ranging from about 1.5 to 4 feet. The fresh glacial till is generally dense to very dense. No ground water seepage was observed in the test pits. CONCLUSIONS We generally concur with the geotechnietl recommendations presented in the previously completed study. In our opinion, the proposed building may be supported on shallow spread footings as rceommended. However, we recommend that structural fill placed within the building pad area for footing or floor slab support be compacted to at least 95 percent of the maximum dry density, determined in accordance with the ASTM D 1557 test procedure. The moitmre content of the on-slte soils appear to be a few percent points above the optimum moishore content for compaction. In our opinion, it will generally be possible to compact the on-site soils to about 90 percent of the MDD at their present moisture content. Compaction to 95 percent of the MDD may require some aeration and reworking of the soils prior to companion,based on our observations of the in-situ moisture content of the on-site soils during excavation of the test pits. It is our opinion that the on-site soils will generally not be suitable for placement during periods of wet weather. We understand that material from it site located at 75th Street Southwest and Hardeson Road may be imported to the site for use as structural fill. The proposed Import material contains some orgastic material and likely has a moisture content above the optimum moisture content for compaction. This material should not be placed In the building pad areas or pavement ate" which will be subjected to heavy traffic. In our opinion, it may be possible to use this raletial as structural fill in pavement ateaa wbich will only be subjected to light vehicle traffic. We recommend that the material be mixed with or placed in alternating layers wiih Bele a materia! to facilitate placement and compartion. Actual placement procedures should he evaluated based on field observations as the material is being placed. We also recommend that the material be capped with a thickness of at least 3 feet of structural fill conustrung no organic material and compacted to at least 95 percent of the MDD. . O ► G e 0 6 n a i a 0 0 m e RIC No.7:21-012 27.100