Galvanized Portion of Anchor Bolts 1

[tabbymulla]

Hi,

Is galvanizing full length of anchor bolts necessary for galvanized bolts or galvanizing the protruded portion only will suffice.

Any guidance is appreciated.

Regards,

Tabby

 

[CELinOttawa]

Interesting question... I don't know what the unintended consequences would be, however concrete is a very good passivating environment for steel corrosion. That also changes over time as the concrete carbonates, but that typically only penetrates to a couple of inches over a very long period in all but the very worst of exposures.

So: Galv all exposed, plus two inches and you should be fine, but I wouldn't be messing with something so well established "just because".

More to the point, I would wonder why you would want to go to the extra bother to only galv a portion of the bolts. We aren't talking about much zinc here!

 

[Duwe6]

Call a galvanizer and check, but I'm pretty sure that getting a portion dipped will be significantly more expensive than having the entire bolt dipped. Galvanizing is a bulk process, and the 'small parts' get dunked into the zinc by basketfuls.

 

[SlideRuleEra]

I agree with CELinOttawa & Duwe6 and have encountered anchor bolts with only the threaded portion galvanized. Another problem with this approach is the anchor bolts have to be protected from weather until shortly before they are encased in concrete, otherwise the ungalvanized portion starts to rust. Fully galvanized anchor bolts can be stored outdoors for weeks or months until used.

Here is a link to a galvanizer that supports Duwe6 with the following statement:

"Anchoring devices (such as threaded rods and anchor bolts) are sometimes specified to be galvanized in the threaded areas only or in the areas to be exposed above ground. This can be more expensive than galvanizing the complete unit because of the additional handling required."

See "Threaded Parts" near the bottom of the link for this quote:

http://www.duncangalvanizing.com/hot-dip-galvanizing/

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[Tmoose]

After a few decades it is not umcommon to find 3/4 anchor bolts rusted and necked down to pencil size.

Poured in place in inertia blocks indoors. Some washdown etc from time-to-time.

 

[tbuelna]

Galvanizing is not an expensive process, and fully galvanizing something like an anchor bolt would not add much cost. The only situation I can imagine for not requiring full galvanize on an anchor bolt would be to prevent rejection of any anchor bolts that had deficient galvanize coating on the surfaces that would be embedded in concrete.