1. Project Location: Baltimore, MD near Baltimore Harbour

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

There were 7 different shapes and sizes to this brick and cobblestone arch structural rehab project, a total of 3275 LF with over 144 tons of rebar, 4,400 CY of grout.

Host pipe sizes      

Type 1=16’ x 5’5”@ 1537 LF

Type 2=19’ x 3’11” @ 150 LF

Type 3=14’9” x 4’9”@ 150 LF

Type 4=19’4” x 4’4”@ 132 LF

Type 5=15’ x 6’4”@ 763 LF

Type 6=15’11” x 5’ @ 459 LF

Type 7=5’ x 7” oval @ 84 LF

3. When was it constructed and how long has it been in service: Construction began in 1820 and continued to expand this storm drain.  It has been in service for over 100 years.

4. Rehab method used:  A combination of spiral wound and modular panels of Danby PLIII 1” profile was used to rehab this pipe, keeping the same shape as the original pipe.

5. Cleaning method used (if required) and who cleaned the line: The interior surfaces of the storm drain were cleaned with a high pressure water blast of ~ 8,000-10,000 psi and debris removal by hand.

6. Method of flow bypass or diversion, if used: Internal weirs was constructed to keep the normal low flow off the immediate work area upstream and downstream to keep the harbor water back, during wet weather events the pipe was evacuated.

7. Depth of pipe:   From 2’ to 6’ below road surface

8. Depth of ground water: N/A.

9. Ventilation and odor control used: Forced air was introduced into the culvert for fresh air.

10. Construction cost (total amount and cost per foot): $6,663,992.35 / $2,034.81 per LF

11. Month and year of start-up and end of construction: June 2012 to September 2013

13. Problems encountered after construction:  Low working headroom in the existing culvert and even lower in the rehabilitated pipes, as low as 2.8 ft. in the center and 1.5 ft. at the sides so the crews got very good at “Duck Walking”, evacuation during storm events, continuously bypass pumped base flow and the downstream 500 ft. was affected by tidal backflows from the Baltimore Harbor outfall.

14. Health and safety:  Used Conventional Confined space protocol, constant weather monitoring.

15. Has any re-inspection been performed?  No.

Reference:

City of Baltimore

Rob Pollack, Robert.Pollack@baltimorecity.gov

Susan Stankiewicz, Susan.Stankiewicz@baltimorecity.gov