108" Concrete Storm Drain

Details

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

Unknown age. Cracks in crown and about 30° from invert possibly caused by nearby excavation causing loss of side soil support.

Dimensions:

Diameter of line, sewer pipe material (RCP, MCIP, brick, etc.), length of rehab portion: 108", Concrete block built-in-place pipe, 655 linear feet; also approximately 60 feet of 120".

Depth of pipe:

15 feet to crown

Depth of ground water:

Five (5) feet of ground water above pipe invert.

Health and safety:

Used conventional confined space entry program

Has any re-inspection been performed? What was the condition of the pipe?

References

Gary Oradat, P.E.
City of Houston (Now with Coastal Water Authority, Tel: 713-658-9020)
Telephone: 713-837-0448
Project: N-0671-01-3

Methodology

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 periods.

Rehab method used:

Danby Panel Lok with full annulus grouting with cementitious grout with minimum compressive strength of 5000 psi. Also used external grouting to consolidate side soil support.

Cleaning method used (if required) and who cleaned the line:

High pressure (10,000 psi) water blasting performed by the Danby licensee (Kinsel Industries, Inc.).

Method of flow bypass or diversion, if used:

None

Hurdles

Problems encountered during construction:

In addition to the cracks, there were several abrupt offsets in the pipe alignment (mostly vertical); at one point, for example, there is the equivalent of a "dropped joint" where the flow channel has a vertical dimension of only 94" while the horizontal diameter is 108". Twelve inches downstream from this point the pipe returns to approximately circular with a diameter of 108". Hurricane induced rains produced surcharge flows when the project was about 75% complete (about 550ft lined, only about 400ft with various grout levels). All work in progress survived without damage.

Problems encountered after construction:

None