Opening of Quotes - Laurel Woods Drainage Improvements Proj No. 121-007 - Selge Construction Co., Inc.

Home Browse Search

Weaver Consultants Group 8 5 CONSTRUCTION CONSIDERATIONS 5.1 Site Preparation The construction of the sewer is substantially an excavation type project. No placement of fill for support of the structure is anticipated for the project. Site preparation is essentially excavation to the sewer invert. Once the new structure subgrade has been established, we recommend the subgrade soils be densified via several passes of a high-energy vibratory compactor. Where the subgrade crosses existing utilities, consideration of the use of light-weight compactor so as not to damage the utility. Where backfill is required around the new pipe and structures, we recommend that it consist of granular structural fill. The structural fill should meet the requirements of Section 5.3 and be placed in accordance with Section 5.4. 5.2 Utility/Storm Water Structure Excavations Excavations should be sloped, shielded or shored in accordance with the current Occupational Safety and Health Administration (OSHA) requirements (see Section 5.7). Once the necessary subgrade level is reached, no addition subgrade preparation is recommended. 5.3 Structural Fill Structural fill, defined as any fill which will support structural loads, should be free of organic material, have a plasticity index of less than 25 percent, a maximum particle size of no more than 3 in., and a maximum dry density in excess of 100 pounds per cubic foot [pcf, as determined by the standard Proctor compaction test (ASTM D698)]. In addition, structural fill should not be frost susceptible. The structural fill should be compacted to at least 9 8 percent of its maximum standard Proctor dry density (ASTM D698) under the foundations and roadways. The near surface soils are considered suitable for use as structural fill. 5.4 Fill Placement Control To achieve the recommended compaction of structural fill, we recommend that the fill be placed and compacted in layers not exceeding 8 inches in loose lift thickness. To observe compliance with the recommended density standards, we recommend that in -place density tests be performed at a frequency of at least one test for every 100 square feet of pipe length per each lift of compacted fill placed in the proposed construction areas. 5.5 Construction Observations We recommend that all pavement and structure subgrades be observed by a qualified Geotechnical Engineer or his representative prior to placement. These observations are to evaluate that the exposed soils are consistent with those encountered in the borings and to check that the materials are of uniform consistency and adequate density.