Corrosion protection of exposed steel
Corrosion protection of exposed steel
(OP)
Is corrosion protection required per code for exposed steel. I have some cable anchors for a large zipline that are not galvanized, but should be. Is this a code requirement, or can they be painted, or can we assume that rust will take some of the steel section over the life of the structure and account for that in the thickness specified?
Thanks!
Thanks!






RE: Corrosion protection of exposed steel
BA
RE: Corrosion protection of exposed steel
What code are you designing to? If the structural steel is external than it should have some form of corrosion protection. If you have specified that the cables are to be galvanized and they need to be galvanized for the integrity of the design, than you should not allow anything less to be installed.
Today I had to pull up a contractor for not galvanizing dowel bars that pass through a cold joint.
Attached is a photo of a W-beam which was within a building for 30+ years and protected with zinc primer but still experienced a minor degree of rusting.
RE: Corrosion protection of exposed steel
RE: Corrosion protection of exposed steel
However, you can design your metal material to have a sacrificial amount of material that is basically an outer layer that is expected to corrode over X number of years. Just depends on a lot of factors. Typically, this is done with metals underground where limited corrosion may occur since oxygen is not present (helical piers for example).
I recommend galvanized steel at a minimum if exposed to the elements. A painted protection just doesn't do it, unless you plan on re-painting every couple of years.
Jim Houlette PE
Web: www.evstudio.us
Online Magazine: www.evstudio.info
RE: Corrosion protection of exposed steel
Sorry, I misread your first post. You were quite clear.
Your photo indicates rust on some of the small connectors. I would think these should be replaced with galvanized fasteners. The painted part is easily inspected and I would be inclined to leave it alone.
BA
RE: Corrosion protection of exposed steel
RE: Corrosion protection of exposed steel
Conversely, you could use this to your advantage if you attach a "sacrificial anode" to the assembly. Generally, the more reactive element will corrode completely before you have to worry about the other elements corroding.
Not sure about cost or whether the fact that three different metals would need to be involved may have unintended consequences, but it may be a solution.
RE: Corrosion protection of exposed steel
Mixing galvanised and ungalvanised steel will cause the gavanising to corrode away quicker, but won't be a problem if it's painted properly.
BTW that split pin doesn't look very tamper-proof, is it in a public area?
RE: Corrosion protection of exposed steel
Thanks for the input.
RE: Corrosion protection of exposed steel
Coating technology has progressed a lot and for future work, you might consider looking into some of the polyurea coatings.
The work can be protected using an active cathodic protection system; to use passive sacrificial anodes, the work has to be continuously wet.
As it stands, it's a matter of periodically inspecting the area and to provide a new coating as required. A zinc rich primer to minimise future corrosion... once it has corroded, the material is gone...
Dik
RE: Corrosion protection of exposed steel
RE: Corrosion protection of exposed steel
RE: Corrosion protection of exposed steel
Hokie, You're right, the grout was not done well...and they had sprinklers wetting everything down until i made them divert the irrigation elsewhere.
RE: Corrosion protection of exposed steel
RE: Corrosion protection of exposed steel
RE: Corrosion protection of exposed steel
RE: Corrosion protection of exposed steel
I'm not sure what's being referred to as "cold galvanising" but I don't think this term can be applied to any brush applied coating (i.e a paint) if anything cold galvanising is electroplating.
The problem seem to be how to destress the tension bars and get everything hot dip galvanised at this stage.
RE: Corrosion protection of exposed steel
http://www.ingal.com.au/FAQ/faq16.html
RE: Corrosion protection of exposed steel
RE: Corrosion protection of exposed steel