Section 12.08.080 Backfilling.
A. Pipe Bedding. Pipe bedding materials from four inches
below pipe to twelve (12) inches
above pipe shall be clean, natural, unwashed gravel, sand or crushed stone, and shall be free from
rocks or stones over one inch in diameter. If suitable material is not found in the trench, the
contractor will be required to furnish material that is suitable. Bedding materials shall be tamped
evenly on both sides of pipe alternately up to not less than twelve (12) inches above the pipe.
Mechanical tampers may be used, provided results equal to hand tamping methods can be obtained.
Material shall be placed in layers not exceeding six inches loose thickness before compaction.
B. Subgrade. The material removed in the excavation may
be used in backfilling to within six
inches of the finished grade line, provided that all material exceeding six inches in diameter is
removed and hauled to waste. None of the following shall be placed in backfill: heavy plastic clay;
hard, dry clay; vegetation or organic material; wet clay, loam or quicksand, saturated sand; frozen
material; pavement; asphalt; brick or other debris. All backfill shall be performed under dry
condition. Materials shall be placed in lifts not exceeding twelve (12) inches in each lift. Each lift
shall be thoroughly compacted. Water compaction of backfill material shall be allowed only upon
written permission from the public works director or designated agent.
C. Material for Top Six Inches. The top six inches of
finished subgrade shall be filled with
suitable material of clean gravel or crushed stone and shall be free from rocks or stones over one
inch in diameter, and shall be thoroughly compacted. All materials, methods of backfill and
compaction shall be approved by the public works director or designated agent. (Ord. 155 (part),
1999: prior code § 12.03.080)
