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<br /> Weaver Consultants Group <br /> <br />1 <br /> <br />1 EXECUTIVE SUMMARY <br />We understand that the city of South Bend is considering the construction of a new storm water <br />drain beginning near the intersection of Lindenwood Drive West and Laurel Wood Drive North <br />and ending at Laurel Road and Auten Road in South Bend, Indiana. The new storm sewer pipe is <br />anticipated to be established at a maximum depth of about 5 feet below the existing ground <br />surface. Other details of the storm sewer such as the pipe diameter and outlet structure are <br />unknown. Given the type of project, we anticipate that the sewer will be constructed using cut <br />and cover techniques. In addition, dry wells are being considered for infiltration of storm water <br />collected from the drainage area. No details of dry wells are known at this time. <br />In general, the subsurface soil profile consisted of granular-type soil to a depth of about 5½ to 11 <br />feet below the ground surface and underlain by silt to a depth of about 9 to 22 feet where sandy <br />lean clay was encountered to the terminal depth of the borings. <br />Given that the storm sewer pipe and associated structures are not anticipated to increase the <br />stresses in the soil above that from the existing structure and overburden, bearing capacity is not a <br />concern. However, to provide adequate support for the proposed sewer elements and maintain line <br />and grade, proper subgrade preparation is critical. For proper preparation of the subgrade, we <br />recommend a program of compaction once the subgrade has been established. Given the presence <br />of existing utilities below the subgrade, we recommend that extreme caution be used in the <br />compaction process in these areas. If dry wells are considered, it is likely the depth of the dry well <br />will be limited to the rather high groundwater level and the presence of more cohesive soil and silt, <br />both of which will restrict infiltration. <br />Once the sewer elements have been set, we recommend that the backfill be placed in an <br />engineering manner in thin lifts and compaction test control. We also anticipated that the road <br />will be re-established at the approximate same line and grade as the existing with a minimum <br />acceptable pavement section. <br />A detailed discussion of design parameters and construction considerations is included in <br />subsequent sections of this report.