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City of Ramsey <br />Project B1705491 <br />August 11, 2017 <br />Page 12 <br />D.2.d. Excavation Dewatering <br />We recommend removing groundwater from the utility excavations if encountered, and removing any <br />water that seeps into excavations from sidewalls or the adjacent sitework. Sumps and pumps will <br />generally be suitable for short-term, small-scale water removal under the soil conditions likely to be <br />encountered for this project. Alternative approaches should be considered for long-term or large-scale <br />groundwater removal, particularly in sands such as those encountered on the project, which can become <br />unstable during dewatering with pumps from within excavations. <br />D.2.e. Corrosion Potential <br />If founded in sandy soils, corrosion protection should not be required for ductile iron pipe. Type I cement <br />may also be specified for concrete utilities. <br />Some clayey soils were present at likely utility depths, which are considered at least moderately corrosive <br />to ductile iron pipe. We recommend corrosion protection or the use of corrosion -resistant pipe material <br />if utilities will be bedded within such soils, particular if in close proximity to static groundwater. Soils with <br />organic content should not be allowed as pipe support or as backfill around pipes. <br />D.3. Construction Quality Control <br />D.3.a. Excavation Observations <br />We recommend having a geotechnical engineer observe all excavations related to subgrade preparation, <br />utility placement and pavement construction. The purpose of the observations is to evaluate the <br />competence of the geologic materials exposed in the excavations and the adequacy of required <br />excavation oversizing. <br />D.3.b. Materials Testing <br />We recommend density tests be taken in excavation backfill and additional required fill placed below <br />pavements and utilities. This includes DCP tests for aggregate base or reclaim and imported granular <br />materials. <br />We recommend Gyratory tests on bituminous mixes to evaluate strength and air voids and density tests <br />to evaluate compaction. <br />D.3.c. Pavement Subgrade Proofroll <br />We recommend that proofrolling of the pavement subgrades be observed by a geotechnical c. isii to <br />determine if the results of the procedure meet project specifications and to delineate the extent of <br />additional pavement subgrade preparation work that may be necessary. <br />BRAUN <br />INinERItC <br />