Preparation/Compaction of subgrade for box culverts.
Preparation/Compaction of subgrade for box culverts.
(OP)
Hello everyone,
A topic come up the other day in our laboratory about why there is no requirement as to the preparation of subgrade for box culverts. Our specifications do not dictate to perform any type of compaction, only excavating to the proper grade and then spraying the base if it is dry prior to placement of concrete.
Why is this done for certain building pads, but not done for concrete culverts for roadways?
A topic come up the other day in our laboratory about why there is no requirement as to the preparation of subgrade for box culverts. Our specifications do not dictate to perform any type of compaction, only excavating to the proper grade and then spraying the base if it is dry prior to placement of concrete.
Why is this done for certain building pads, but not done for concrete culverts for roadways?





RE: Preparation/Compaction of subgrade for box culverts.
www.PeirceEngineering.com
RE: Preparation/Compaction of subgrade for box culverts.
RE: Preparation/Compaction of subgrade for box culverts.
We were told that and that does seem to make sense. Thank you
cvg,
We have yet to find a specific spec from any municipality or agency that specifically states that you should do any type of subgrade prep, if you find one I would like a link to it.
RE: Preparation/Compaction of subgrade for box culverts.
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Preparation/Compaction of subgrade for box culverts.
Actually I just googled this and I don't have time to sort out all the Virginia DOT references to other sections of their spec that got me to this section, but it appears this falls under the requirements of section 305.03, which requires scarification of the top 6" of the existing material and recompaction to a given specified density that varies according to the percent of the material retained on a #4 sieve.
RE: Preparation/Compaction of subgrade for box culverts.
RE: Preparation/Compaction of subgrade for box culverts.
RE: Preparation/Compaction of subgrade for box culverts.
www.PeirceEngineering.com
RE: Preparation/Compaction of subgrade for box culverts.
The S T A i am familiar with spec.s out the allowable backfill as well. In extreme conditions dewatering is required. Certainly some support is achieved after proper compactive effort is utilized. Lots of spec.s on box culvert placement.
RE: Preparation/Compaction of subgrade for box culverts.