Bolts or nails...

[EngBure]

I am designing a pole barn type structure and have 6x6 posts @ 8' o.c. Between each post are two 2x12's which support the trusses. The owner would like to have the post sandwiched between the 2x12's and I am trying to figure out the best way to attached the 2x12's to the posts. My load on the 2x12's is 805 lb/ft. I was planning on calling for three 3/4" bolts to support the end of each 2x12 but is there some kind of nail I could use? Thanks.

 

[EngBure]

actually I would be using four 3/4" bolts.

 

[woodman88]

I do not like the connection and would have to do some very careful calculations before considering it with the use of thru bolts. I would not use nails or even wood screws/lag screws for your loads.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[msquared48]

I would go with 6X8 columns and let the 2X12/s into the top of the 6X8 for a bearing conection rather than relying on the bolts or nails entirely.

Mike McCann
MMC Engineering

 

[ishvaaag]

As per old values in DIN 1052, 25 4.6mm diameter 130 mm long nails deliver 1812 kgf, so 3624 kgf for two details like that or 8000 lbf.

As long as you are sharing the load equally between the 2x12's, the loads you give are service level, and you are ready to go with nails, the schedule in the image, where the red circles are the nails joining one of the beams to the post, and the blue ones those that join the other beam to the post, is enough. In each side beam, separation is 1 inch horizontally and 2 inches vertically.

 

[ishvaaag]

If going for nails, use better this one in the same but diagonalized setup, less destructive to the post.

Anyway I concurr with msquared that positive support be better, and woodman more or less in the same intent. This is just if you prefer nail ways. Even the bolts might ultimately be more reliable than the nails to disengagement or lack of serviceability.

 

[dik]

Can you dap the 2x12's into the post so that you have a bearing surface as well as stability by nailing the 2x12's to the post?

Dik

 

[IRstuff]

Why couldn't you use the hangers like those in residential houses? They look somewhat like an upside-down U-bracket with yokes on the two arms of the U for the cross members to be inserted and nailed. The crook of the U would then sit on top of the post.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[csd72]

As others have said, I would do my best to avoid relying on the bolts or nails for permanent support and utilise a system where the loads are transferred by bearing and the nails/bolts are ised only to hold it in place.

Timber splits and often makes bolted connections unworkable.

 

[Teguci]

10d or 12d nails. Nails are preferred since they can be installed quickly and economically. An additional block can be nailed below the header beams if you need more space for more nails due to the load.

As an aside, make sure you do a lateral analysis on your posts. A 6x6 lam post is more like a 4x5.25 post and will have problems in bending for higher wind loads and building heights exceeding 10ft.

 

[Splitrings]

Here is a copy of my standard design I use in Vermont. I thru bolt double 2x10's to both sides of 6x8 posts. I am not a fan of notching the top of a post. It is typically done with a chainsaw and the vertical cut is always over cut. There is also considerable lateral load applied to the top of these posts. This causes tension perpendicular to the grain if you use a notch.

 

[a2mfk]

Maybe someone else said it and I missed it, but what about a pre-fab connection by Simpson or similar? They make those nice looking black ones also...