Rectification of drainline

[junpal]

I need help in the rectification of drainline the RCP pipes and inlet/outlet structure is above the design elevation of about 750mm, based on the actual condition pipes adjacent to the inlet is only 120mm above the bottom surface of the subbase material, our CQC recommend that to remove the pipes and structure inlet/outlet and re-install to correct design elevations but that I think is costly. any recommendation like cast reinforced concrete around the pipes for protection, but our CQC is not satisfied to this because when compaction of subbase start the concrete might be broken...
Thank You

 

[LHA]

Less than 5" cover over RCP? That is not acceptable under a roadway. But you said the line is 29.5" above design.

I agree with the inspector, poured concrete 5" thick will not last long under a road. And, once it breaks, it will most likely have less structural strength than the subbase would.

Minimum cover for RCP under a roadway is 18", so you can relay the pipe and have 16" to spare.

Relaying two pipes and one inlet will be far less expensive than doing that plus replacing the broken curb, road and sidewalk beside it next year.

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve