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1 <br /> b. Unsatisfactory soil materials are those defined in ASTM D-2321 <br /> soil classification designation Class IV and V along with peat and <br /> other highly organic soils. <br /> 2. Materials shall be furnished as required from off site sources and hauled <br /> to the site. <br /> B. Foundation <br /> 1. A stable foundation must be provided to insure proper line and grade is <br /> maintained. Unsuitable foundations must be stabilized at the engineer's <br /> 1 direction. Unsuitable or unstable foundations may be undercut and <br /> replaced with a suitable bedding material, placed in 6" lifts. Other <br /> methods of stabilization, such as geotextiles may be appropriate based <br /> on the engineer's judgment. <br /> C. Bedding: <br /> 1. A stable and uniform bedding shall be provided for the pipe and any <br /> protruding features of its joints and/or fittings. The middle of the bedding <br /> equal to 1/3 of the O.D. should be loosely placed, with the remainder <br /> compacted to a minimum of 90% standard proctor density. Class I, II, and <br /> III materials are suitable for use as bedding. <br /> D. Haunching <br /> 1. Proper haunching provides a major portion of the pipes strength and <br /> stability therefore care must be exercised in insure placement and <br /> compaction of the embedment material in the haunches. For larger <br /> diameter pipes (>30°) embedment materials should be worked under the <br /> 1 haunches by hand. Haunching materials may be Class I, II, or III and <br /> must be placed and compacted in 8" maximum lifts, compacted to 90% <br /> standard proctor density. <br /> E. Initial Backfill: <br /> 1. Initial backfill materials are required to a minimum of the pipe diameter for <br /> proper structural performance of the pipe. The ASTM specifications <br /> extend the initial backfill from the springline to 6°-12° above the pipe to <br /> provide protection for the pipe from construction operations during <br /> placement of the final backfill and protect the pipe form stones or cobbles <br /> in the final backfill. For proper structural performance of the pipe, the <br /> initial backfill need only extend to the pipe diameter. Class I, II, or III <br /> materials may be used as initial backfill however: <br /> a. Class I materials must be used in wet trenches if Class I bedding <br /> 1 <br /> b. and haunching materials are used. <br /> Class II materials must be compacted in 6" lifts to 90% standard <br /> proctor density. <br /> c. Class III materials must be compacted in 6" lifts to 90% standard <br /> proctor density. <br /> 05/08 02221-4 05-4893 <br />