Laserfiche WebLink
Mr. Sam Roberto <br />Project BBXX- 01 -119A <br />May 24, 2001 <br />Page 5 <br />C.S. Groundwater Considerations <br />Groundwater is likely to be encountered in excavations extended below the existing fill, and into <br />the underlying swamp- deposited peat. The present information suggests that it may be possible <br />to control groundwater with sumps and pumps, and by limiting excavation dimensions and <br />backfilling the excavations quickly. <br />D. Recommendations <br />D.1. Building Subgrade Preparation <br />D.1.a. Excavations <br />We recommend removing the existing 611 and swamp - deposited peat from below the proposed <br />building footprint, and from an area that extends one foot horizontally outside the footprint for <br />each foot the excavations extend below the bottoms of the perimeter foundations. The present <br />information indicates that excavations will extend approximately 10 feet below the existing <br />ground surface. <br />Estimated excavation depths should be considered the minimum necessary to provide a stable <br />platform on which to spread and compact replacement backfill. Depending on construction <br />conditions, excavations may ultimately have to be extended locally to remove unstable alluvial <br />and glacial soils. <br />D.1.b. Excavation Stability <br />The existing fill and swamp- deposited peat are Type C soils under Department of Labor <br />Occupational Safety and Health Administration (OSI -IA) guidelines. Excavation sideslopes <br />should therefore be maintained at gradients equal to or flatter than 1 1/4:1 (horizontal:vertical), or <br />be shored. <br />