How to Account for Corrosion in Steel Anchor Threaded Rods

[steel_plate_arch]

Hi.

I'm working on a wall design that involves using steel anchor rods (0.75" diameter, threaded) attached to a metal deadman corrugated sheet.

I'm looking to account for corrosion loss in the diameter of steel rod, but I'm not sure on what resources/equations would apply to this type of structural member. Are there any sources that anyone might know of?

Thanks

 

[SlideRuleEra]

I'm looking to account for corrosion loss in the diameter of steel rods...

Measured or calculated loss of diameter which will reduce the tensile stress area.

http://www.SlideRuleEra.net

 

[BAretired]

Depends on the grade of steel and the contaminants in the soil regime. The following is a brochure from one manufacturer:

https://www.aatprod.com/threaded-rod-materials/

Here is some info on corrosion rate:

https://galvanizeit.org/corrosion/corrosion-process/corrosion-rate

BA

 

[r13]

SRE has posted info on the rate of corrosion in the linked thread, it might help if the section lost in time is the concern. Link

 

[STrctPono]

I don't have any publications for estimated corrosion rates because I don't believe that threaded rods are normally one of those things that people try and account for corrosion loss in the design. That's more typical with elements such as HP piles, pipe piles, casing around drilled shafts, and sheet piles.... A 3/4" threaded rod is not that large and even a small amount of corrosion can be significant. I've never understood why people use non stainless steel threaded rods for deadmans. I just don't see the life cycle cost analysis panning out in their favor. I get it, people do it all the time... but I prefer ASTM A193/B8M for this type of scenario. I can sleep better at night.

 

[Agent666]

One thing you need to watch out for is thinking you are making it better by galvanising your threaded rods. Once the galv is gone in a localised region, corrosion is focused in that area with much higher rates of material loss locally.

You are better encasing it in concrete to protect it if it is in the ground if its an option.

The area where steel goes into any concrete is also an area of high corrosion potential, often requiring additional protective measures in this zone.

 

[steel_plate_arch]

I appreciate all the replies. This is some really good information.

I typically don't account for corrosion rates in the rods since we do galavanize anyway, but I have a DOT asking about it (and rightly so) as it is a critical part of the system. Also, I think they just want to see more numbers to feel better about it.