Emergency 72" Manhole Replacement

Project Location
Atascocita, TX
Construction cost
$298,002
Construction Start/End
05/2017 - 07/2015

Details

Dimensions:

72” manhole with force main, fully deteriorated manhole removed and replaced. 30” line had a complete failure blocking the flow to the sewer plant., 20’ deep

Depth of structure:
20 VF
Health and safety:
Used conventional confined space entry program
Has any re-inspection been performed? What was the condition of the structure?
Yes, found to be in excellent condition
References

Brown & Gay Engineers, Inc.
281-558-8700

Methodology

Prior to installation of the Danby liner, the contractor installed 20 VF of liner plate, then began reconstructing the manhole with a double mat of rebar then installed Danby PL3E flat panels and 1’ thick structural concrete in walls. The 12” force main was tied in using a custom fabricated HDPE force main drop. An 8’x8’x18” thick concrete manhole lid was also constructed with the underside having the corrosion resistant Danby PVC liner. This manhole was constructed by Boyer, Inc. of Houston, Tx

Method of flow bypass or diversion, if used:
Temporary flow diversion of the upstream pipe directly to sewer plant

Hurdles

Problems encountered during construction:
None
Problems encountered after construction:
1) Prior to construction, a utility pole 10' from manhole was in jeopardy of sinking with the surrounding ground sloughing off. 2) Remove blockage in 30” downstream line, reinforced with steel pipe, CIPP full from manhole to sewer plant