66” x 66” Semi-Elliptical Sewer

1. Project Location: Joint Outfall “A” Unit 3C Trunk Sewer, County Sanitation District No. 2.

2. Diameter of line, sewer pipe material (RCP, MCIP, brick, etc.), length of rehab portion: 66” x 66” Semi-Elliptical Sewer made of unreinforced concrete with clay tile lining. Original project was designed as 1305’ of rehab but later reduced to about 800’.

3. When was it constructed and how long has it been in service: Unknown age. Many clay tiles had fallen off and the exposed concrete was severely corroded

4. Rehab method used: Danby Panel Lok with full annulus grouting with cementitious grout with minimum compressive strength of 5000 psi. Panel Lok flat panels arched from “J” strip anchors at invert corners. No lining of invert. Section under railroad track had 4” of grout and steel rebar designed by District’s structural engineers.

5. Cleaning method used (if required) and who cleaned the line: High pressure (10,000 psi) water blasting performed by the Danby licensee (Sancon Technlogies, Inc.).

6. Method of flow bypass or diversion, if used: None. Pipe was out of service.

7. Depth of pipe: 3 to 5 feet to crown.

8. Depth of ground water: No ground water.

9. Ventilation and odor control used: Fresh air pumped into pipe at upstream manhole, and suction fan at downstream manhole to provide adequate ventilation during the work periodsrow.

10. Construction cost (total amount and cost per foot): Unknown because of negotiated change in scope. Danby estimates $690/ft.

11. Month and year of start-up and end of construction: August 1 -October 20, 1999.

12. Problems encountered during construction: None. Transitions into and out of the thicker grout wall section, as well as from semi-elliptical pipe into circular 60” pipe slowed normal productivity. Danby and licensee sought and received permission to change grout mix design to lower heat of hydration in thicker section.

13. Problems encountered after construction: None.

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

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


Jane Fongrow

County Sanitation Districts of Los Angeles County

Telephone: 562-699-7411, ext. 1631