MPBZ vs 6x6 with sleeve enbedded in concrete

[HouseBoy]

I spec'd the Simpson Moment Post Bases (with the associated reinforcing around).
The contractor thinks he can position the posts more precisely if he can simply embed the posts into the pier foundation (with concrete AND a protective sleeve).
(This is for a 25 ft x 15 ft pavilion - A fancy patio roof)
It seems that the moment capacity and stiffness should be similar in that the piers would be similar and the limiting factor would be the 6x6 itself.

Has anyone used "Post Protectors" or a similar product?

Mainly interested in how they might affect moment and uplift resistance. (I have 10 posts total) Drift is prob L/150 under design load. Should be fine for the intended use.

Thoughts about these two options?

 

[jayrod12]

Moment I'd agree that an embedded post is likely similar capacity to the simpson base. I wouldn't necessarily agree for uplift since you're relying on friction only.

What I'd be more concerned about is replacement of the posts when they inevitably rot at the interface between the wood and concrete at top of pier.

 

[phamENG]

Post locating should be fairly similar. The way I usually see it done is that they dig the hole, set the post in it, brace it so it's plumb and the elevation is set correctly, and pour the concrete. They can do the same thing with the post base. Just screw the post base onto the bottom of the post and do the same procedure. Setting the elevation may be a little more challenging depending on on the size of the post, but not by much.

But to your question, no - haven't used them. If the expected life of the structure is more than 10 years, I don't embed wood in concrete around here. I'll try to make a moment connection work at the roof before I embed the post. Easier to repair that if it loosens up than try to re-establish a fixed base column when it rots.

 

[XR250]

I do it that way frequently. Add some lags or nails to the face for uplift resistance.
Spec the cut end at the top to minimize the potential for rot.
I imagine it will outperform the Simpson stuff as you take the flexibility of their product out of the equation (but may not last as long).

 

[HouseBoy]

Pham - I TRIED to do that (moment connection at the top) since I too thought that would be much simpler all around but the contractor thought otherwise.
I got another one where the owner (who is a construction management guy) doesn't want moment capacity at the top OR the bottom!
Sometimes it's hard to outguess these guys!

I actually like the embedded post approach IF I can get happy with the rot protection strategy.

Thanks

 

[JStructsteel]

Never used the pole protectors, seems like it would not change much. Add some bars or 2x4s at the bottom for uplift.

Have you looked at the Permacolumn system?

 

[dauwerda]

I actually like the embedded post approach IF I can get happy with the rot protection strategy.

Specify posts with a minimum treatment level of UC4C and you shouldn't have a problem.

http://www.woodscienceconsulting.com/wood-science-consulting-blog-/2018/10/2/use-of-treated-wood