Dry set concrete anchors

[Food Scientist]

Looking for opinions as my research has come up with less than conclusive evidence but see no reason why it won't work.

I'm building a post frame structure and for the foundation I am doing concrete piers and attaching brackets to the pier. Most videos I see using piers the bracket is using a wet set method where as the building package I bought has dry set anchors which I see is typically used for slabs or poured walls.

Its not in the budget to do a poured wall and I don't trust myself enough I can accurately place all 30 brackets in wet concrete, so I actually prefer the dry set as this is the first time I've done a project this big and want to do it right.

The data provided by the bracket supplier shows the uplift rating for the wet set anchors is 9000 lbs and the dry set to be 7000 lbs. My location in Michigan doesn't experience a lot of wind, code is 90 mph. Shear strength is about 6600 lbs for wet and 3800 lbs for dry set.

So the question is if the connection between the dry set bracket and the pier does fail, is it going to be any different than a failure between a dry set bracket set into a poured wall? I don't think it will, I figure the bolts/concrete will break before the entire foundation fails.

To be clear I am planning to use dry set brackets in concrete piers and are asking if that will fail differently than a dry set bracket in a poured concrete wall. Thanks.

 

[doitmyself]

Having just completed a very simple railing project install on concrete porch , the one specification you should take into account is pier size and the distance your bolts are from the pier edge. Depending on fastener depth, if the fastener is too close to the pier edge, tension and shear load strength can be diminished.

All of the fastener mfg. have tables showing this: https://www.itwredhead.com/portals/0/fmproductcatalog/documents/products/93/ldtsubmittal.pdf

I'm not an engineer and don't know you experience level. I found it a blessing to use a new SDS Plus bit in a rotary hammer drill (vs. regular hammer drill).....https://www.youtube.com/watch?v=6UMY4lkcCqE ... You want excellent quality holes with Tapcon type fasteners. I ended up using an adhesive anchor system.

Hopefully someone with experience beyond DIY level will chime in.

 

[Linctex]

Unless your pier is a REALLY large diameter, I think your anchor bolts will be too close to the edge with this.

Drill a big hole in the center of that U and use one large anchor bolt in the center of the pier (or just buy the right brackets)

 

[Linctex]

LOL, we were responding at the same time....

 

[Food Scientist]

Using 24" piers. Brackets are 12" edge to edge so the holes will be slightly less. According to the table I found from Simpson Titen HD screw type anchors, the critical edge distance is 6-3/8". So call it 11" center to center on the bracket plus 6.5" plus 6.5" gives me 24".

Also the 24" is big enough that I won't go over the load bearing capacity of the soil (sand).

Using 5/8" x 6" screw type anchors. Embedment depth in the table is 5.5".

 

[zzyzzx]

Are you comfortable with setting some in wet concrete?

Last time I did something like this, I used a template to get the stuff in wet concrete in the right places. It wasn't perfect, but close enough. The scale was pretty small though.

 

[doitmyself]

I'm curious - why are you using 24" x 42"+ piers vs. using a typical pole building footing and post system or the system described by this company: https://www.midwestpermacolumn.com/

Numerous options: in Michigan, I am not aware of builders pouring concrete around the wood post.

In retrospect, I would be inclined to ask your bracket manufacturer about your question just in case we are missing something. You are correct that nobody seems to address using dry fit brackets on piers.

 

[Food Scientist]

Originally Posted by zzyzzx
Are you comfortable with setting some in wet concrete?

Last time I did something like this, I used a template to get the stuff in wet concrete in the right places. It wasn't perfect, but close enough. The scale was pretty small though.


On a small scale or something that would be built around the posts, then yes. Until I get some experience that follows a blue print, no.

 

[Food Scientist]

Originally Posted by doitmyself
I'm curious - why are you using 24" x 42"+ piers vs. using a typical pole building footing and post system or the system described by this company: https://www.midwestpermacolumn.com/

Numerous options: in Michigan, I am not aware of builders pouring concrete around the wood post.

In retrospect, I would be inclined to ask your bracket manufacturer about your question just in case we are missing something. You are correct that nobody seems to address using dry fit brackets on piers.


I am using what would be considered a typical pier system in the sense that the pier is 42" to the frost line, then I will make a tapered cone down to 54" for the footing, all done in a monolithic pour. I could easily get by with a smaller pier diameter if I was using a wet set method. What I am afraid of happening is I will mis-measure or overlook something and have to dig the pier out, so I'd rather get the pier in the right location and then fine tune the bracket location where I can check and double check everything is right. I think Midwest Permacolumn will sell what makes the most sense for the contractor and is sound engineering. Doubt too many contractors will stay competitive with so much material and labor tied up into the piers.

I did talk to the manufacturer and from what I remember what I'm doing is fine, (the bracket will fail in the same method as a poured wall) but being that I can only find literally one example I wanted to reach out for more info. I don't mind making mistakes, just don't like making expensive ones.

Since the pier is about the same size as a 55 gallon drum, I was thinking to mix up some concrete, attach the bracket and lift it up. It won't be the same load, but if it fails in that then I will do a wet set and try to not screw up.

From an earlier post about the anchors needing to be a certain distance from the edge, I find it interesting that a lot of these dry set brackets are placed on poured walls which are no where near wide enough to meet the minimum distance. That alone in my mind makes a pier better.

 

[doitmyself]

Yea, if you go to page 9 of the "Sturdi Wall Design and Use Guide" below, the edge distances are smaller. It would be interesting to hear why from an engineer. On page 5 they do mention use on a pier: "The concrete foundation shown could be a wall or rectangular pier". Their minimum edge distance for 5/8" fastener is 5", so you should be good at 6.5".

https://www.midwestpermacolumn.com/manuals click open Concrete Anchor Brackets, then Sturdi Wall Design and Use Guide

With the wet set method, don't you just align the brackets to a taught string line?

 

[PimTac]

Would there be any benefit to using J bolts instead of these concrete anchor bolts? Pardon my ignorance in this particular situation but in my previous experience in anchoring supports to concrete we used the J bolts. With that said I've not worked with this particular type of system before.

 

[Food Scientist]

Originally Posted by PimTac
Would there be any benefit to using J bolts instead of these concrete anchor bolts? Pardon my ignorance in this particular situation but in my previous experience in anchoring supports to concrete we used the J bolts. With that said I've not worked with this particular type of system before.


J bolts or wet set anchors in general are stronger and the preferred system of setting anchors, I'm not confident enough I won't place the anchor in the right location on all 30 piers. Even 1/2" off can give you problems, worse if I set the bracket out of square and plumb.

 

[Food Scientist]

Originally Posted by doitmyself
Yea, if you go to page 9 of the "Sturdi Wall Design and Use Guide" below, the edge distances are smaller. It would be interesting to hear why from an engineer. On page 5 they do mention use on a pier: "The concrete foundation shown could be a wall or rectangular pier". Their minimum edge distance for 5/8" fastener is 5", so you should be good at 6.5".

https://www.midwestpermacolumn.com/manuals click open Concrete Anchor Brackets, then Sturdi Wall Design and Use Guide

With the wet set method, don't you just align the brackets to a taught string line?

Reading through it looks like they are referring to setting an anchor offset to the edge of a pier for door openings. On page 6 they do show in the diagram the 5" distance as well and a 10" minimum width of the pier. Not sure why the pier needs to be rectangular, but doubt a circular pier in larger dimensions will be worse. Below is a screenshot from the Simpson Titen showing the edge distances.

For the string line yes I could that, just afraid I'd have a bracket turned or not completely level and not find out until the concrete has set. Once I get some experience I will try doing a wet set.

 

[Food Scientist]

So from what I'm gathering what I'm planning to do isn't necessarily wrong or incorrect, just not the preferred method. The reasons why it's not preferred can be many, but most importantly I haven't heard it won't hold up and cause the building to collapse. I know from an engineering standpoint the wet set is superior in many ways, but my construction skills are not. If this was a small building (like an outdoor kitchen I plan to build in the future), then I would totally do the wet set.

Doitmyself I think we are having a good discussion, learned a lot and see you are putting in some effort into your research.

 

[PimTac]

Originally Posted by SVTCobra
Originally Posted by PimTac
Would there be any benefit to using J bolts instead of these concrete anchor bolts? Pardon my ignorance in this particular situation but in my previous experience in anchoring supports to concrete we used the J bolts. With that said I've not worked with this particular type of system before.


J bolts or wet set anchors in general are stronger and the preferred system of setting anchors, I'm not confident enough I won't place the anchor in the right location on all 30 piers. Even 1/2" off can give you problems, worse if I set the bracket out of square and plumb.





I understand. Looking at that bracket in the picture above it would be good to have some setting adjustability with the anchor holes so you could adjust the bracket to be straight if a bolt happened to be off.

 

[doitmyself]

Originally Posted by SVTCobra
Doitmyself I think we are having a good discussion, learned a lot and see you are putting in some effort into your research.

It's an illness. When I chose to install porch railing (to code) on 60 year-old concrete last autumn, I had to educate myself and I accumulated about 30 bookmarks on the subject. Fastener type: wedge/adhesive/screw. Material: stainless due to salt exposure-316 is better,LOL. Fastener placement (edge/center/etc.). I was all set to order special stainless screw type when a respected contractor told me he HATED screw type with a passion. His comments bothered me enough that I chose to go the adhesive route, which then required a LOT more research, LOL. Speaking of adhesive systems.......notice their high pull out and shear strength....... https://www.itwredhead.com/Portals/...ead%20Concrete%20Adhesive%20Brochure.pdf
A peek under my rail post covers:

 

[Food Scientist]

Thanks! I'll do some more research, but it looks like if I went with the adhesive the C6 would be my choice for the high strength (13163 lbs). Surprisingly Simpson Titen is rated for 9800 lbs for the 5/8 vs 10000 for the cheapest line, the G5.

 

[tahoe_hybrid]

they are illegal to use for permanent structures

 

[zzyzzx]

Originally Posted by doitmyself
I was all set to order special stainless screw type when a respected contractor told me he HATED screw type with a passion.


Contractor's only want to do what is easiest for them to install. No regard is given to longevity.

 

[Food Scientist]

Originally Posted by tahoe_hybrid
they are illegal to use for permanent structures

Could you provide a link?

Found a video of a Titen HD screw type that broke the concrete before the anchor broke. 8000 lbs on a 1/2" Titen screw type anchor in 2500 psi concrete.

That is what I'm guessing the designer at these companies aim for is the concrete breaks before the anchor/adhesive does.