1. Pipe Post Installation Inspection Demonstrations

2. Background
More states and municipalities embrace the use of Closed Circuit Television (CCTV) Inspection
Storm drain pipes and culverts,
Observing cracks in reinforced concrete pipe (RCP)
Not armed with enough information to properly interpret the video inspections
Uneducated eye will interpret hairline cracks as detrimental to the service and performance.
In part do to a lack of understanding
How RCP is designed to crack under load
What different cracks in RCP mean
Also due to the magnification available in modern CCTV
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Pipe Inspection Demo

3. Background (cont.) Standard design procedure
Supporting strength of RCP based upon the load required to develop a 0.01” crack.
0.01” crack can be misinterpreted that an installed pipe has reached failure,
AASHTO LRFD Bridge Construction Specifications (Section 27) allow cracks up to ten times this width (0.10”) in installed RCP without repair.
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Pipe Inspection Demo

4. Background (cont.) Post Installation Inspection Demonstration
Use CCTV inspection equipment that is used in the field
Pre-cracked RCP laid above ground
Inspectors and other stakeholders to compare cracks
Actual cracks in pipe vs CCTV image of crack
Allows a better understanding and interpretation of the inspection data.
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Pipe Inspection Demo

5. Planning Start promoting early
Engineers – Municipalities – DOT’s
The larger the event, the longer it will take to get a suitable date scheduled.
Hold the event at a pipe plant if possible.
Conduct a tour of the facility
Observe a three-edge bearing test
Reinforces the strength and attributes of RCP
Partner with an inspection company
Equipment used in the field will be demonstrated
Field experiences will be relevant
Actual reports can be provided
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Pipe Inspection Demo

6. Planning (cont.) RCP Recommend double cage reinforcement HDPE
large enough to crawl into and measure the cracks
36” diameter for setup
60” or larger for three-edge bearing test
Recommend double cage reinforcement
Large cracks less likely to pass through the wall
Provides a better looking specimen
HDPE
15”- 24” works well for the flexible pipe
40 LF - (2) 20’ pieces
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Pipe Inspection Demo

7. Set up The demo consists of four “stations” Presentation area
Inspection equipment area
Plant tour of RCP production
Three Edge Bearing test station
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Pipe Inspection Demo

8. Set up Presentation Equipment Begin with a short introduction
Explain the importance of Post Installation Inspections
Include an overview of what the guests will see
Conduct in break room or QC lab
Equipment
Power point presentation and projector.
Microphone and P.A. as required
20 minutes presentation - chairs are not needed.
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Pipe Inspection Demo

9. Set up
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Pipe Inspection Demo

10. Set up Inspection Equipment Area
Need area with pipe joined up on ground.
RCP setup:
Two sections “pre-cracked” for inspections
Two addition uncracked sections for the equipment to crawl through (four total sections)
HDPE setup:
Two sections (40 L.F.) deflected (clamped)
CCTV Setup
Position the inspection van at the end of pipe.
TV monitor outside of the van for group to viewing.
May need a pop up shelter to cut glare from the sun.
Computer monitors not compatible
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Pipe Inspection Demo

11. Set up
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Pipe Inspection Demo

12. Set up Plant Tour Establish a staging area
Create manageable group sizes
Staff groups accordingly
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Pipe Inspection Demo

13. Set up Three Edge Bearing Test
Have TEB Machine preloaded (as large as possible)
Load pipe up to an 0.01” crack (stop loading)
Allow attendees to observe and measure crack
Release load and witness the cracks close back up
After all groups observed 0.01” crack - load to ultimate
Point out ultimate load then continue to failure
Stress the additional strength capacity of the pipe
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Pipe Inspection Demo

14. Set up
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Pipe Inspection Demo

15. Hand out information Full copy of AASHTO Section 27
One page “Summary” according to AASHTO Section 27
ACPA CP Info – “Cracks in Installed Reinforced Concrete Pipe”
Optional 0.01” feeler gages from ACPA
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Pipe Inspection Demo

16. One Page Summary information:
AASHTO LRFD Bridge Construction Specifications call for all buried pipe culverts to undergo internal inspection to evaluate issues that may affect long-tern performance.
Section describes potential cracks observed in concrete pipe culverts and a simplified summary is as follows:
Crack less than or equal to 0.01”
These cracks are minor & OK
Crack between 0.01” and 0.10”
Evaluation required: is it detrimental and in a corrosive environment? (PH<5.5)
If non-corrosive or not detrimental – OK
If corrosive and detrimental – Seal crack
Crack equal to or greater than 0.10”
Evaluation required: is crack detrimental to structure?
If not detrimental – OK
If detrimental – repair and seal crack
If not repairable – remediate or replace
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Pipe Inspection Demo

17. Can purchase shim stock in 0.05”, and 0.10”
Other information
Can purchase shim stock in 0.05”, and 0.10”
(DIMES WORK WELL ALSO – DIME = 0.05” width)
Have a set of feeler gages available for guests.
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Pipe Inspection Demo

18. Set up a dry run the day before the event.
Dry Run & Set Up
Set up a dry run the day before the event.
Expect last minute updates and setup changes.
Sometimes the inspection equipment is “brand new” and just “out of the box.”
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Pipe Inspection Demo

19. Try to get an 0.01” crack for inspecting.
Dry Run & Set Up (cont.)
Try to get an 0.01” crack for inspecting.
May require taking the pipe to or just beyond ultimate on the three edge bearing tester.
For the larger cracks, use dimes to shim open.
0.05” crack can be measured with the laser micrometer
Half the size referenced in AASHTO Section 27.
Note that the 0.10” crack reference in AASHTO Section 27 would be the width of two dimes stacked together.
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Pipe Inspection Demo

20. Set up RCP with the spigot end away from the van
Dry Run & Set Up (cont.)
Set up RCP with the spigot end away from the van
Use a gasket hold black plastic sheeting
Provides for proper lighting for the video / laser
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Pipe Inspection Demo

21. Dry Run & Set Up (cont.)
¾” coil rod and 4”x4”s to deflect the HDPE pipe
The CCTV equipment has a difficult time picking up deflection less than 10% without the use of laser profile equipment
Use a gasket to hold the plastic on the HDPE
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Pipe Inspection Demo

22. Day of event Two hours is plenty of time for this demo.
Suggest starting at 10:00 am and wrapping up with pizza and soft drinks for all.
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Pipe Inspection Demo

23. Objectives Guests leave with the following understanding
Post Installation Inspection must be performed on flexible pipes
Laser Profile Equipment will give best results and should be required in the specifications
Post Installation Inspections performed on RCP
Expect to see cracks
Understand what the expected cracks in RCP should look like
CCTV equipment will magnify the cracks
Minor cracks in storm drain concrete pipes are not a concern
Sealing of these cracks should not be required
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Pipe Inspection Demo

24. Post Installation Inspection Demo
Don’t be nervous
It is not difficult
It does take planning
It will take time
It is effective
It is very rewarding
QUESTIONS?????
Talk to us!!!!
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Pipe Inspection Demo

25. Pipe Post Installation Inspection Demonstrations