evaluating number of fasteners for top mounted vs side mounted point loads on multy ply beams 1

[lubos1984]

Hello All,

Wanted to get some direction for point loads on a 2 ply LVL beam for different loading scenarios.

Scenario 1: face mounted point load (point load from attached beam on joist hanger)

Scenario 2: top mounted point load (point load from column above)

Assuming the same member properties , two row nailing pattern and point load "p", would calculating the fastener capacity be different for each case ?

For scenario 1: would calculating shear capacity of fastener be Z = P/4. This assumes each ply shares 1/2 of the load of P.

For scenario 2: since the fastener is essentially transferring all the load to the other ply would Z = P/2 for this case ?

Just wanted your thoughts on how the two scenarios affect the nail capacity for calculation purposes.

Thanks!

 

[SWComposites]

Would help greatly if you posted some sketches of these two joints.

 

[lubos1984]

 

[lubos1984]

sorry about the messy sketch. I've had a situation where a municipality is asking for minimum nailing requirements for various point load situations on some floor layouts. I'm looking to create a formula for the different scenarios based on fastener capacity.
Thanks again.

 

[phamENG]

The LVL manufacturers have all of this worked out already. Take a look at the literature for the beam to be used. They have typical details for these conditions with number and size of fastener based on the point load.

 

[ChorasDen]

The LVL manufacturers have all of this worked out already.

This is true, but the OP question is still a reasonable question to address in case they have criteria that falls outside of the manufacturer guidance, or if there is interest in back checking the manufacturer's tables.

Lubos, below is some notes I have saved that discuss this method, hopefully they are clear enough to follow, I can provide more context if needed. The pictures have been resized so they are not super clear, but might be better if you right click and save as to view locally.

 

[ChorasDen]

To add, the idea is to make a free body diagram where the load is applied between the ply that directly takes the load and the fasteners between this ply and the alternate plies to understand how to calculate the shear applied to each fastener.

 

[lubos1984]

ChorasDen thank you so much for this and all of you for your help.