For the Bedding Zone, if the trench was undercut below the bottom of the pipe, what should you do?

For the Bedding Zone, if the trench was undercut below the bottom of the pipe, what should you do?

• A. Loosen the soil in the bottom of the trench immediately below the approximate middle third of the outside diameter of the pipe
• B. Place bedding material and leave it in a loose condition below the outside diameter
• C. Place the bedding material and leave it in a loose condition below the middle third of the outside diameter of the pipe
• D. Remove all bedding material from trench

Answer: (C)

When the trench has been undercut under the bottom of the pipe, the bedding must be restored with material and left loose in a controlled way. The goal is to provide a support that can mold to loads and allow proper settlement without creating excessive stress on the pipe. Placing bedding material and leaving it loose below the middle third of the pipe’s outside diameter achieves that. It fills the voids under the pipe and gives a compressible, even bearing in the lower portion, while avoiding overly rigid support that could transfer stress or cause point loads. This specific zone of looseness helps the pipe settle evenly with the backfill as it compacts above it. Loosening soil without adding bedding wouldn’t give the pipe proper support, and leaving bedding loose all the way under the pipe or removing bedding entirely would either fail to support or create voids.

When the trench has been undercut under the bottom of the pipe, the bedding must be restored with material and left loose in a controlled way. The goal is to provide a support that can mold to loads and allow proper settlement without creating excessive stress on the pipe.

Placing bedding material and leaving it loose below the middle third of the pipe’s outside diameter achieves that. It fills the voids under the pipe and gives a compressible, even bearing in the lower portion, while avoiding overly rigid support that could transfer stress or cause point loads. This specific zone of looseness helps the pipe settle evenly with the backfill as it compacts above it.

Loosening soil without adding bedding wouldn’t give the pipe proper support, and leaving bedding loose all the way under the pipe or removing bedding entirely would either fail to support or create voids.