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38C-057 Soil Investigations Results Discussion 11-14-12ss [ A S S O C I A T E S ] EnvironmentalSafetyHealthGeotechnical 293 Bridge Street   Suite 500  Springfield, MA 01103  Tel 413 788 6222  Fax 413 788 8830  www.oto‐env.com  Olsen Property - 380 South Street Northampton, Massachusetts Summary of Investigations November 14, 2012 1.0 Summary of Investigations  We observed 3 test pits on November 1, 2012. They extended to a depth of between 4.5 and 6 feet deep. A site sketch, test pit logs and photographs are attached. 2.0 Summary of Subsurface Conditions  Ground surface consists of 4 inches asphalt in each test pit location.  Approximately 1 foot of sand with little amounts of gravel and occasional cobbles was observed immediately below the asphalt layer.  Below the sand and gravel layer, each test pit encountered soft, fine sand and silt with varying amounts of debris and organics. The test pits did not fully penetrate the soft, organic soils due to water entering the test pits and cave-in of soils.  Groundwater was observed to be entering the test pits at a depth of 4 to 4.5 feet below ground surface. 3.0 Recommendations  The debris fill and soft organic soils are not suitable foundation bearing materials.  The fill materials are likely variable in thickness and stiffness. Furthermore, the soft soils are compressible and the organic material may decay over time, resulting in differential settlement.  We recommend review of the following options to address the unsuitable fill materials : o Removal of unsuitable soils in their entirety (down to a suitable bearing material) and replacement using compacted engineered fill. Note that additional investigations would be needed to determine the depth of a suitable bearing surface. o Construction of a stiff mat foundation, so that the load is distributed evenly over the footprint of the structure and to cause it to settle uniformly. In this option, it may be possible to remove only a portion (upper one to two feet) of the unsuitable materials. o Pile foundation alternative, such as helical piles or other pier system, to transfer the building loads through the unsuitable materials and into a firm bearing material. A recommended contractor is: Atlas Systems of NE, Dennis Geisser - 800-688-9774 This report is subject to the attached Limitations. Attachments: Site Sketch, Test Pit Logs, Photographs, Limitations c. Ryan Hellwig O:\J2400\2424 Laidlaw Design\01-01 380 South St Northampton MA-Geotech\Soil Investigations Results Discussion 11-14-12.doc LIMITATIONS 1. The observations presented in this report were made under the conditions described herein. The conclusions presented in this report were based solely upon the services described in the report and not on scientific tasks or procedures beyond the scope of the project or the time and budgetary constraints imposed by the client. The work described in this report was carried out in accordance with the Statement of Terms and Conditions attached to our proposal. 2. The analysis and recommendations submitted in this report are based in part upon the data obtained from widely spaced subsurface explorations. The nature and extent of variations between these explorations may not become evident until construction. If variations then appear evident, it may be necessary to reevaluate the recommendations of this report. 3. The generalized soil profile described in the text is intended to convey trends in subsurface conditions. The boundaries between strata are approximate and idealized and have been developed by interpretations of widely spaced explorations and samples; actual soil transitions are probably more erratic. For specific information, refer to the boring logs. 4. In the event that any changes in the nature, design or location of the proposed structures are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report modified or verified in writing by O'Reilly, Talbot & Okun Associates Inc. It is recommended that we be retained to provide a general review of final plans and specifications. 5. Our report was prepared for the exclusive benefit of our client. Reliance upon the report and its conclusions is not made to third parties or future property owners.