Concrete Bedding is Easier to Bed than Clay

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Message: Concrete bedding installs relatively quickly, without the need for compaction under pipe haunches

Concrete bedding was used successfully in this Montana dam. Placing and encasing the 170-ft, 48-inch concrete outlet conduit was estimated to cost $133,000 (2013 cost). Six days of work effort were required to construct the foundation of the spillway riser, excavate the outlet conduit trench, and place the outlet conduit (including concrete bedding placement).

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  This photo shows the excavated embankment with the bottom compacted. The pipe trench will be excavated from this compacted surface.

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  Excavating pipe trench.

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  The trench has been excavated. The pipe is being set on Pipe Support Blocks.

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  Pipe support blocks were spaced four feet apart.

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  Setting the last pipe segment before setting drop inlet riser.

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  Drop Inlet set in place.

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  After pipe support blocks were set and the drop inlet riser was connected, high-slump concrete bedding was poured in the trench.

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  Concrete bedding around drop inlet riser.

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  Placing the concrete cap over the pipe.

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  Installed pipe with concrete bedding and cap.

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  Example detail of bedding configuration.

Note: The content on this page was originally created as part of DamOutletWorks.org (DOWL, 2018). It has subsequently been updated and reformatted as part of the Dam Safety Toolbox.
Revision ID: 4715
Revision Date: 12/02/2022