2008-213 (5) - Laserfiche WebLink

Home Browse Search

3.03 ALIGNMENT, GRADE AND COVER FOR BURIED PIPING SYSTEMS A. Gravity sewers shall be laid and maintained to the required lines, depths, and grades. B. Wherever obstructions not indicated on the Drawings are encountered during the progress of the work and interfere to such an extent that an alteration in the Drawings is required, the Engineer will order a deviation from the line and grade or arrange with the Owners of the structures for the removal, relocation, or reconstruction of the obstructions. C. The maximum permissible deflection for pipe and fittings shall be as recommended by the manufacturer. D. Installation of gravity sewers shall be controlled by use of a laser to maintain proper grade. The Contractor shall also be responsible for verifying elevations of the pipe, as indicated on the Drawings, at sufficient points during progress of the work to identify discrepancies between actual and plan elevations due to laser misalignment, equipment error, etc., and to correct the work as required to conform to the Drawings. 3.04 PIPE TRENCH EXCAVATION A. Trench Dimensions 1. The minimum width of the trench shall be equal to the outside diameter of the pipe at the joints plus 8 inches for unsheeted trenches, or 12 inches for sheeted trench, and the maximum width of trench, measured at the top of the pipe, shall not exceed the nominal pipe diameter plus two feet, unless otherwise shown on the Drawing details or approved by the Engineer. Trench walls shall be vertical from the bottom of the trench to a line measured one foot above the top of the pipe. From one foot above the top of the pipe to the surface, the trench walls shall be as nearly vertical as soil conditions will permit, unless otherwise detailed on the Drawings. Spaces for joints, fittings, manholes and other structures shall be maintained unless otherwise approved by the Engineer, or alternate methods are detailed on the Drawings. Should the specified maximum width of trench be exceeded, the pipe shall be adequately reinforced as directed by the Engineer, at the Contractor's expense. 2. Trench grade for utilities or structures not requiring special bedding material shall be defined as the grade of the bottom surface of the utility or structure to be constructed or placed within the trench. Such shaping of the trench bottom, as may be required to provide suitable bedding, shall be considered to be a part of this work. Trench grade in non -cushioning material shall be defined as 6 inches below the outside of the bottom of the utility, which 6 inches shall be backfilled with suitable bedding material. Unauthorized excavation below trench grade shall be backfilled to trench grade and suitably compacted by the Contractor without additional cost to the Owner. Final trimming and grading of trench bottom shall be done manually. 3.05 BACKFILL AND BEDDING MATERIALS A. TYPE 1 - Type 1 material shall be either well -graded crushed stone or crushed gravel meeting the requirements of ASTM Designation C33 -71a, Gradation 67 (3/4 inch to No. 02530 — Gravity Sanitary Sewer Piping 02530- 4 J