Post Anchors - Need Help

[daBear]

Thank you very much for all the comments and discussion. Here are a couple of old shots taken during construction. The slab does not have poured trenches around the perimeter. It is just a slab but it is 6" thick and has fiber and wire in it. I want to put a gable shingle roof over the existing pad which will have a 12' inside ceiling height clearance for the RV. Then come off the right side as you are looking at the pad with a lean-to roof which will be the tractor shed.

 

[Egon]

The idea of using a sill plate would be very appealing for me in your situation.

Keep things as simple as possible.

 

[2manyrocks]

Unless the cost of anchor plates drops dramatically, I, too, think sill plates are better for cost effectiveness and to spread the load. I guess you'd end up drilling for galvanized or stainless anchor bolts and bonding them in the cement with hydraulic cement or expoxy.

 

[studor]

Are you planning to side or sheath the building? If so, I don't think you even need the T brackets, -- the 2x6 lagged into the bottom of the post, then anchored and lagged into the concrete will stop any lift -- (ordinary shields with a dollop of construction adhesive are mighty hard to pull out -- the lags will pull through the board first) . Whether the sill plate is continuous or just out a foot or two out will work about the same. The siding or sheathing will stop any side to side movement. For the shed roof part I assume you were just going to sonotube and post anchor into the concrete and tie the posts together with a top plate.
I have seen "floating pad" construction used in a lot of buildings in poor soil and bad weather conditions -- if the pad has not cracked so far, I don't think its going to (even with the posts added)

 

[daBear]

Not planning on siding the building, at least not yet maybe later. The lean-to part will be post in concrete since that is over dirt now.

 

[MarkV]

I think you should reconsider the plan. A 16x40' roof structure that is sheathed and covered with asphalt shingles has a lot of weight. Building it open sided like a pole barn transfers all the weight to the individual posts, as you know. These individual point loads are now going to rest on the edge of a 6" slab. Even with a strong slab like yours, it is well under the standards for a point load footing, particularly setting on the edge of the slab.

MarkV

 

[F.L. Jennings]

Suggestion; Place your posts outside of the perimeter of the present concrete. This will bypass post to concrete connection problems. The size of the structure will change somewhat but benefits should outweigh negatives.

If it is to be an enclosed structure then filler concrete can be added later.

Getting a good connection to the slab is possible, but too thin a slab with concentrated loads could be a problem.

I've used a core drill before to go into existing heavy concrete, and then set all thread bars in epoxy (masterbuilder's) grout to hold down large vibrating equipment ( wood chipper). Same method will work for relatively static loads that can have large uplift forces.

 

[daBear]

Points are well taken about making post footings off the slab. This is the reason I posted the question and it seems the overwhelming consensus is off slab post footings.