Beam Strength

[Engineer22]

Which material is most dimensionally stable?

From left to right- Glulam, Sister beam, Solid sawn, and Flitch.

 

[Mithrandir918]

Flitch beam,

Beam stability referes to lateral torsional stability.  The flitch, when transferred to all the same material by the modular ratio will give the biggest area (or wdith) which will give the biggest moment of inertia in the Y and more stability.

Pretty sure on this but not positive.

 

[tenguy23]

I agree with Mithrandir if the question is more based on beam stability; the steel plate will surely increase the effective width & increase r,y.

The last time I heard the term "dimensionally stable" was in my old Materials Lab Class in college; this is from memory, but I thought that related more to resistance to environmental / material-matrix effects (temperature & thermal cracking come to mind)...like a ball of cement could crumble under freeze-thaw cycles, but including good angular aggregate will improve its dimensional stability.

Looks like I have to find my old materials text book...

 

[Engineer22]

Thanks everyone! I am still torn between glulam and flitch beam..

 

[tj_PE]

Thanks everyone! I am still torn between glulam and flitch beam..

look ONLY at the dimensional properties - of comparable materials.

as said above, if you do a transformed section of the steel added to the wood, and it gives you a larger S and I, as long as it's not a super slender or "flat" beam, then I would say the flitch.