A storm drain pipe is laid directly on large rock fragments in the trench bottom. The crew wants to backfill immediately because the slope is correct. What is the concern?
Correct Answer
A) Pipe bedding must support the barrel uniformly and protect the pipe from point loads
Underground pipe needs proper bedding to support the barrel and prevent point loads that can crack, deform, or settle the pipe. Other choices ignore support and material protection.
Why This Is the Correct Answer
Underground pipe needs proper bedding to support the barrel and prevent point loads that can crack, deform, or settle the pipe. Other choices ignore support and material protection.
Why the Other Options Are Wrong
Option B: Rock bedding always increases pipe flexibility
In mechanical and plumbing, Rock bedding always increases pipe flexibility is the wrong selection for Underground pipe bedding: it solves the wrong trade problem; the field result tied to Underground pipe bedding is Pipe bedding must support the barrel uniformly and protect the pipe from point loads.
Option C: Select slope alone controls pipe performance for underground pipe bedding
The trap in C is Slope alone controls pipe performance. That selection is wrong because the option shifts to a different trade task; the tested Underground pipe bedding function or field correction is Pipe bedding must support the barrel uniformly and protect the pipe from point loads; Underground pipe requires proper bedding and uniform support.
Option D: Base the underground pipe bedding response on metal pipe needs bedding
Choice D gives Only metal pipe needs bedding. Its specific error: it leaves the work at an informal or incomplete stage, while Underground pipe bedding requires Pipe bedding must support the barrel uniformly and protect the pipe from point loads.
Memory Technique
Use the phrase "problem, control, result" for underground pipe bedding; the result side is Pipe bedding must support the barrel uniformly and protect the pipe from point loads.
Reference Hint
Open Pipe and Excavation Contracting, 2011; use the index entry or section for "Pipe bedding and support" to confirm that Underground pipe needs proper bedding to support the barrel and prevent point loads that can crack, deform, or settle the pipe.
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