Lateral Stability of built up wood beam.
Lateral Stability of built up wood beam.
(OP)
Is any one aware of a design procedure to determine the allowable bending stress of a Nailed Built-Up Beam laterally unsupported except at the ends.
The NDS has provisions for Nailed Built-Up Columns but I have not found any provisions for beams.
I would think the use of the same reduction factors per the column equations would be reasonable. Another engineer I work with thought that would be too conservative.
The NDS has provisions for Nailed Built-Up Columns but I have not found any provisions for beams.
I would think the use of the same reduction factors per the column equations would be reasonable. Another engineer I work with thought that would be too conservative.





RE: Lateral Stability of built up wood beam.
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RE: Lateral Stability of built up wood beam.
RE: Lateral Stability of built up wood beam.
RE: Lateral Stability of built up wood beam.
If the built-up beam was a column instead of a beam then you could use equation 15.3-1 to calcualte the capacity of the built-up column. When you use equation 15.3-1 you reduce the capacity when bucklin in the weak direction controls.
When a column is built-up of seperate members the buckling resistance is increased. However testing has shown that slip between the laminations will reduce the column efficiencies by 20%-30% or more.
Applying this to my beam it seems that I should reduce the capacity below that given by equation 3.3-6. I should be conservative if I use the same reduction factors as those used in equation 15.3-1. I was just curious if any one is aware of any similair testing that has been down on built-up beams.
RE: Lateral Stability of built up wood beam.
ANSI/AF&PA. 2001. ANSI/AF&PA NDS-2001.
RE: Lateral Stability of built up wood beam.
entire section will control and not buckling of an individual lamination, I think you are fine using the beam stability equation. Compression and flexure of side-by-side laminations have different behaviors.
Also, technically, you may have to reduce the strong axis buckling of a built-up column (and not the weak axis) if the l/d of the built-up strong axis is greater than the l/d of the built-up weak axis (which could be the individual member strong axis).