Wood Member End Nailing Capacity 1

[JrStructuralEng]

Does anyone know what shear capacity I can expect (if any) from end nailing into wood lumber. (i.e. nailing through one piece of lumber into the end grain of another piece)

Or if you know where I can find such info that would be great! I have looked for quite a while now and can't find much.

 

[Lion06]

It won't be much, but look in the NDS. All the equations are in there.

 

[Lion06]

The factor just for going into the end grain is 0.67 (found on page 78 of the NDS. You also have to comply with min edge distances and take reductions as required.

 

[SlideRuleEra]

The USDA Forest Products Lab's book "Wood As An Engineering Material" also addresses nails in end grain. See page 7-6 of Chapter 7, Fastenings, free .PDF download at this link:

http://www.fpl.fs.fed.us/products/publications/several_pubs.php?grouping_id=100&header_id=p

The recommendation is essentially the same as StructuralEIT's information from NDS.

This in not surprising; on many subjects NDS requirements are based on research performed by FPL.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[JrStructuralEng]

I need to fit 3 nails into the end of a 2x8 (tight)

I could use a framing anchor but it is a repetitive detail so I was trying to avoid that.

 

[msquared48]

Personally, I would never end nail any connection. I would look to another way to solve the problem.

Mike McCann
MMC Engineering

 

[Ron]

Framing anchors are cheap compared to your liability....use them.

End nailing is not a good idea. I agree with Mike.

 

[hokie66]

Not really up on current wood framing practice, but Ron and Mike, do you mean you would use framing anchors on all stud to plate connections?

 

[msquared48]

No Hokie.

The end nails there are in bearing. If there is lateral shear, the plywood nailing would transfer the force, not the end hailing.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

That's end Nailing. Sheeeesh...

The primary function of these nails is to keep the studs aligned to the plates, top and bottom.

I distrust the endnail connection to transfer load due to the working of the nails in the end grain with time, with the connection eventually failing, whether if be pullout or shear. Far easier to bend a nail laterally in the side grain than the end grain due to the strength of the side grain. More likely to cause localized splitting of the end of the stud rather than bend the nail in the end grain scenario.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

As stated in the "Douglas-Fir Use Book", page 209, under End Grain:

"The withdrawl resistance of nails and spikes into end grain is quite low, and connections of this type should be avoided where possible. The allowable lateral load per nail or spike whjen driven into end grain is two-thirds of that for nails or spikes driven into side grain."

The book is outdated regarding allowables, but the general counsel just as valid.

Moreover, the pullout scenario happens also in cases of a bending connection, not just direct pullout.

I just stay clear.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[hokie66]

I certainly agree that you can't use end grain nails in tension. My query was just about transferring the wind load perpendicular to the wall from stud to plate.

 

[msquared48]

Ah...

Well, usually not a concern in areas of low wind with plywood on the outside of the wall. However, in high wind load areas such as Ron has to deal with, I can see where that could be necessary.

Occasionally for large window walls, I have to do that for the large verticals, top and bottom.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[Ron]

hokie66...no, not on stud to plate connections because you have other interactions helping out. In that application the axial compressive load on the studs helps out a great deal. Additionally, the tension ties required for overturning and uplift help to maintain tight contact between plate and stud.

My concern is more the applications where you can have outward movement of the perpendicular member such as joists and some header applications.

 

[hokie66]

Sure, then we agree.