Inclined screws in wood under tension

[PROFR]

I am trying to connect two LVL beams as shown below in which one of them will be under tension. I am using inclined lag screws. I checked the tension capacity of the screw embedded in member (b) considering the end grain condition and it is OK. I am not sure how to check the screw capacity in member (a). It there any check needed here?

 

[r13]

jim,

I doubt your theory and claim for comparing the effectiveness of direct nailing and sunk nailing, if connection method is not to be changed.

 

[BAretired]

Pilot holes prevent the wood from splitting:

BA

 

[NorthCivil]

knife plate connection?
gussets on the sides?
screws alone not appropriate here, IMO

 

[jimstructures]

Retired13,

Read the first line in BAretired's post after "Getting screws to hold in end grain". That is a very well known condition and it has been recommended to avoid nails and screws in tension in end grain.

Note I am not talking about screws and/or nails in compression as in nailing studs to plates or similar.

I agree that BAretired's solution is a reasonable alternative, but very time consuming and expensive and I seen it used in furniture but never in wood construction. Maybe that shows my lack of experience, but I have never seen that method used in house carpentry or wooden buildings.

Jim

 

[r13]

How about this technics? Link

 

[XR250]

Here's a trick which may be worth considering.

Use that trick if you never want to get hired by that customer again!

 

[BAretired]

Use that trick if you never want to get hired by that customer again!

I suspect you are correct, but I thought it was rather an ingenious way to solve the problem.

BA

 

[r13]

It is really depending on the purpose of the application, is it structural or architectural (furniture), the acceptance of the effort/cost would be quite different.

 

[jimstructures]

retired13,

The technics link is a wood screw thru end grain (first piece) into cross grain (second piece). Essentially reversing the original question and arriving at BAretired's solution.

Jim

 

[WeezerMike1]

I know a lot of folks here have voiced concerns about getting screws or nails to hold in end-grain. That's certainly something to consider, but that's more of a problem with wood screws, nails, sawn lumber, and thin lumber. That concern might have been overstated for this particular application.

LVLs dont split in the same way that sawn lumber does. Lag screws have larger threads that take more splitting to disengage the threads. Lag screws should be pre-drilled to reduce splitting.

I think we can all agree it's a bad idea to sink four 1/2" diameter lag screws into the end of a 3x6 sawn member, but Four 3/8" lag screws into the end of an LVL 3.5x9.25? That shouldn't be a problem.

With that said, the use should also be considered. If a connection failure collapses a 300 sq ft deck down into a canyon, then yeah... forget the code and the forces and just detail the hell out of it.

 

[r13]

Another wild idea