60" Manhole Replacement - Atascocita, TX

1. Project Location:  Atascocita Rd, Atascocita, TX

2. Diameter of line, sewer pipe material (RCP, MCIP, brick, etc.), length of rehab portion: 60” RCP Manhole with a 8” Force Main, 17 VF – walls were fully deteriorated from H2S corrosion

3. When was it constructed and how long has it been in service: Unknown

4. Rehab method used: Prior to installation of the Danby liner, the contractor installed 17 VF of 6’ ID liner plate, then began reconstructing the manhole with a double mat of rebar then installed Danby PLIII flat panels 8’ vertical sections.  The 8” force main was tied in using a custom fabricated 12” 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 reconstructed by Boyer, Inc. of Houston, Tx

5. Cleaning method used (if required) and who cleaned the line: N/A – Manhole was excavated out

6. Method of flow bypass or diversion, if used: Internal by-pass inserting an 18” line in the upstream pipe connecting to the downstream 21” line

7. Depth of pipe: 17 VF

8. Depth of ground water: N/A.

9. Ventilation and odor control used: Forced Air provided air circulation

10. Construction cost (total amount and cost per foot): $237,437

11. Month and year of start-up and end of construction: 2-2-2016 to 3-12-2016

13. Problems encountered after construction: Prior to construction, nearby communication and utilities were in jeopardy of sinking with the surrounding ground sloughing off.

14. Health and safety: Used conventional confined space entry program.

15. Has any re-inspection been performed?  No


Alene Efaw

Brown & Gay Engineers, Inc.