Pipe Post Installation Inspection Demonstrations

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 Slide 2 - 06.2010 Pipe Inspection Demo

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. Slide 3 - 06.2010 Pipe Inspection Demo

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. Slide 4 - 06.2010 Pipe Inspection Demo

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 Slide 5 - 06.2010 Pipe Inspection Demo

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 Slide 6 - 06.2010 Pipe Inspection Demo

Set up The demo consists of four “stations” Presentation area Inspection equipment area Plant tour of RCP production Three Edge Bearing test station Slide 7 - 06.2010 Pipe Inspection Demo

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. Slide 8 - 06.2010 Pipe Inspection Demo

Set up Slide 9 - 06.2010 Pipe Inspection Demo

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 Slide 10 - 06.2010 Pipe Inspection Demo

Set up Slide 11 - 06.2010 Pipe Inspection Demo

Set up Plant Tour Establish a staging area Create manageable group sizes Staff groups accordingly Slide 12 - 06.2010 Pipe Inspection Demo

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 Slide 13 - 06.2010 Pipe Inspection Demo

Set up Slide 14 - 06.2010 Pipe Inspection Demo

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 Slide 15 - 06.2010 Pipe Inspection Demo

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 27.6.4 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 Slide 16 - 06.2010 Pipe Inspection Demo

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. Slide 17 - 06.2010 Pipe Inspection Demo

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.” Slide 18 - 06.2010 Pipe Inspection Demo

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. Slide 19 - 06.2010 Pipe Inspection Demo

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 Slide 20 - 06.2010 Pipe Inspection Demo

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 Slide 21 - 06.2010 Pipe Inspection Demo

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. Slide 22 - 06.2010 Pipe Inspection Demo

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 Slide 23 - 06.2010 Pipe Inspection Demo

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!!!! Slide 24 - 06.2010 Pipe Inspection Demo

Pipe Post Installation Inspection Demonstrations