Author Topic: Diy pier/beam connectors  (Read 3196 times)

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Offline busted knuckles

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Diy pier/beam connectors
« on: October 10, 2015, 08:17:10 PM »
Would I be foolish to make my own pier to beam connectors? I was thinking of say 3 inch wide,1\8 in thick flatbar with a 1 inch leg bent at the bottom. Approx 16 inches long. 8 inches in the concrete and 8 inches above to nail or bolt the beam to.  One per side. So 2 per pier.  Looking forward to your replies.

I have no inspections or code to comply with.
you know that mugshot of Nick Nolte? I wish I looked that good.

Offline Don_P

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Re: Diy pier/beam connectors
« Reply #1 on: October 11, 2015, 03:57:43 AM »
I agree with the concept but I think 1/8" is too light.  What I have been contemplating but have not talked with an engineer about is to use heavier bar stock to create T's that are cast in. The I is bolted to the post or fully cast in a concrete pier and the - is bolted to the girder. There is enough length and width to fully reinforce that joint and its' connections against the lateral forces on the building. The environment is corrosive... although I have been watching youtubes on zinc plating  ;D

Offline busted knuckles

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Re: Diy pier/beam connectors
« Reply #2 on: October 11, 2015, 08:28:23 AM »
Going heavier is not an issue. I wondered about the rust. Is there a paint that will stand up to the situation?  Also, nails or bolt the beam to the connectors?

If I went heavier, say 1\4 inch or 3\8… could one per pier do the job?
you know that mugshot of Nick Nolte? I wish I looked that good.

Offline Don_P

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Re: Diy pier/beam connectors
« Reply #3 on: October 11, 2015, 03:41:07 PM »
Probably something like heavy primer and then undercoating, or even tar foundation coating ??? Once the steel is 3" inside concrete, beyond oxygen, it is safe. The plate should probably have rebar studs welded all along it down in the concrete.

In a flitch plate beam a layer of steel is sandwiched between two bolted sideplates of dimensional lumber. The steel is carrying the load and the lumber is there to keep the steel plate from buckling.

That takes care of the "in plane" direction. The corners would need a 90 degree corner plate and then the endwall piers with their plates would brace the adjacent direction.

The bolts through the steel plates sandwiched in the beam will be trying to split the girder as the pier tries to rotate. The length of the plate in the girder is what reduces that tendency, longer is better.

Offline flyingvan

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Re: Diy pier/beam connectors
« Reply #4 on: October 11, 2015, 07:11:33 PM »
    There are epoxy products specifically for this application.  They need to be reapplied periodically....

    I don't remember seeing the topic of steel corrosion in concrete discussed here.  Rebar will corrode very quickly outside, but once embedded it slows way down---by about a factor of 1,000.  Concrete is pretty alkali stuff with a Ph of 12 or so.  In the high Ph, a thin oxide layer forms and prevents the metal atoms from dissolving---this is where Don's 3" comes into play.  Get the rebar too close to an edge and things can get to it.  Oxygen does some damage but not as much as CO2 (you form carbonates and drop the Ph and the protection along with it).  If your concrete mix was too wet to start with you increase permeability, allowing stuff to get to the steel.  Another enemy is chlorides, and if you can mix your concrete in chloride free water it'll serve you better.   Winter salt can be a bad source of chlorides too.  It can get through cracks or permeable concrete and the chloride ions probaby attack the protective layer of oxides the concrete has formed....
    Any of these conditions will allow the steel to start binding with oxygen.  It'll expand  and push out the concrete
    Oh one other source of rebar failure--if it's touching any dissimilar metals you've created a battery and hydrolysis will occur.   
     In a nutshell---embed your rebar.  Mix your concrete with only enough CLEAN water to make it workable. 
Find what you love and let it kill you.

Offline busted knuckles

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Re: Diy pier/beam connectors
« Reply #5 on: October 14, 2015, 08:22:08 PM »
Thanks for all the information. I am having a cement company do the concrete, they have specific strength mixtures for foundations. I have made up some brackets from some hot roll steel. 24" x 3" x 1/4" thick. They are getting hot dip galvanized this week. 2 metal straps per pier, sandwiching the beam on each side.
you know that mugshot of Nick Nolte? I wish I looked that good.

 

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