# Metro North CT DOT Bridge Inspection



## NACE (May 16, 2008)

Last night we tested the film thickness and number of coats on structural steel for CT DOT/Metro North Bridge using a Tooke Gauge


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## Jmayspaint (Mar 26, 2013)

That's cool. Did it pass?


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## NACE (May 16, 2008)

On average yes


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## CApainter (Jun 29, 2007)

What kind of material was used?


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## NACE (May 16, 2008)

Zinc on white metal blast. Intermediate mastic and polyamide topcoat. Caroline. 9-12 mils DFT. All three coats different colors. DOT wanted Tooke gauge analysis. Modern DFT gauges not applicable. 2X knife on Tooke gauge spec'ed with 6 replacement plates analyzed. All plates were done at shop. DOT said their analysis determined that coating "barely" met spec. "Barely" in my book meets spec. That's what we found in average. Don't know why they wanted test cuz bridge is getting Recoated because bridge is too low and trucks scrape the I beams every day and Metro North trains vibrate the daylights out of the steel 24/7 every 30 minutes not including Amtrak. 
Fun evening and a profitable inspection.


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## mustangmike3789 (Jun 11, 2011)

Nice work NACE. I can honestly say that I have never had to do a bridge inspection off of a ladder and I dont envy you for that. 
One reason for using the tooke or PIG, is to get an assessment of the layers of paint and the total thickness of each layer to determine if the existing coating can support and accept a new coating system over it. I am surprised that you weren't also required to do some adhesion test to also be sure that the existing coat has the ability to hold from the weight and pull of the new system.
I dont get to use the tooke to often but I did use it last month when I took the SSPC BCI 2. I have a few jobs coming up the will get an overcoat on the existing areas that may require the tooke and some adhesion testing.


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## NACE (May 16, 2008)

DOT was asking to have six support plates that were Coated in a contractors shop and installed after the bridge was painted. They had done their own testing and concluded that the plates "barely met specification" they requested that the GC contract a NACE inspector to verify their findings on the six plates. Hence the ladder for the location of the plates. A little nerving when when you are up on a ladder with a Tooke gauge and either Metro North or Amtrack Ocela without warning is inches from your head at 70 mph. DOT guys don't even flinch and I'm soiling myself. Anyway, pull tests were not in their scope so we did what was on the manifest. Really don't understand their reasoning as the bridge is going to be re-blasted and re-painted since so many repairs and structural changes have occurred. They were very easy to work with and very appreciative we accommodated them at 10:30 at night.


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