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42" Hampton Roads Sanitation District Rehab


1. Project Location: Hampton, Virginia.

2. Diameter of line, sewer pipe material (RCP, MCIP, brick, etc.), length of rehab portion: 42", RCP, 1910 feet of rehab.

3. When was it constructed and how long has it been in service: Installed during WW II (about 1943).

4. Rehab method used: Danby Panel Lok III (spirally wound) with full annulus grouting with cementitious grout with minimum compressive strength of 7500 psi.

5. Cleaning method used (if required) and who cleaned the line: High pressure water jetting and vactor cleaning with some hand tool scraping performed by subcontractor.

6. Method of flow bypass or diversion, if used: Flows 100% pumped (about 6 mgd) around entire length of project via two 12" welded joint HDPE pipes. Laterals remained active at all times.

7. Depth of pipe: 8 - 15 feet.

8. Depth of ground water: To surface (adjacent to marina and siphoned under river).

9. Ventilation and odor control used: Fresh air pumped into pipe past upstream air dam; maintained sealed lids during non-work periods, and adequate ventilation to carry odors downstream during the work periods.

10. Construction cost (total amount and cost per foot): $600,000 / $314/ft.

11. Month and year of start-up and end of construction: October (late) 1992 - February 1993.

12. Problems encountered during construction: Ground water seepage was a continual problem, requiring local suction pumping and, in especially bad locations, ground dewatering pumps (see attached photos). Heavy rains and high (flood) tides surcharged upstream pipes, requiring the removal of the pipe plugs and bypass pumps and reinstating full flow (10-12 mgd) to the project pipeline before annulus grouting; there was no damage to the liner which only had manhole bulkheads in place (see attached photos).

13. Problems encountered after construction: None.

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

15. Has any re-inspection been performed? What was the condition of the pipe? No.


Reference:
Mr. Bill Salley, P.E.

Hampton Roads Sanitary District, Virginia

Telephone: 757-460-2261