×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Below Grade Steel

Below Grade Steel

Below Grade Steel

(OP)
I am looking for a good solution to protecting W shapes below grade. They will be supporting a concrete pan deck cantilevered over a cliff as the foundation for a house (NOT the best idea I know!) Most will start about 8' below grade (attached to rock anchors) then eventually be out exposed to atmosphere. I was thinking epoxy coating or a spray-on bituminous coating. Any other ideas???

RE: Below Grade Steel

(OP)
JAE-thanks...nothing had come up in my searches but this one will help.

RE: Below Grade Steel

The Google Search works better than the Eng-Tips search at this time.

RE: Below Grade Steel

I would recommend two coats of high-build, high-solids epoxy, such as International Paints Interzone 954, to a dry film thickness of 500 microns (~ 20 mils).

RE: Below Grade Steel

Maybe an active cathodic protection system?

RE: Below Grade Steel

I agree with SlideRuleEra - Hot Dip Galvanize it.

RE: Below Grade Steel

(OP)
my concern with hot dip galvanizing is that when backfill is compacted on top of the beams the galvanizing would be damaged. I am currently thinking of two options:
1. encasing the beams in concrete

2. Using a combination of active cathodic protection as well as a spray on bituminous coating.

Does anyone know of a good resource for the cathodic protection?

Thanks for all of your responses

RE: Below Grade Steel

Of course, you should do what you consider best but hot-dipped galvanized steel is self-healing if the  coating is damaged (zinc in surrounding areas continues to provide corrosion protection to the damaged area).

It is paint, including bituminous coatings, that fail when the coating is damaged (corrosion begins at the spot of the damage).

www.SlideRuleEra.net idea

RE: Below Grade Steel

My preference would be hot dip galvanising (or a good zinc-rich paint) and encased in concrete.

Galvanising is a lot more robust than most paints and provides cathodic protection to damaged areas, as SlideRuleEra pointed out.

I consider active CP overkill for this situation unless it is an aggressive environment.

RE: Below Grade Steel

You could oversize the steel section to be able to lose some cross sectional area and still be able to carry the load.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources