laminated beam 2

[rittz]

How to calculate moment of inertia of built up beam comprised of 2 pcs 1/4" x 8" plates laminated to 2 or more 2x10 wood timbers.

 

[Lion06]

You'll have to transform the wood to steel or the steel to wood. You need to have all pieces as the same material to have I be of any use to you. I like to make everything steel. Find the modular raio, n=Es/Ew. Make the thickness of the wood equal to the actual thickness divided by n. The just find I like you would any other section - assuming the centerlines are at rhe same depth it's just (bh3)/12.

 

[woodman88]

These types of beams derive most of it's strength from the steel plates with the wood members providing bracing to prevent buckling of the steel plates. If you search the posts for “Flitch” you will find a thread “Flitch plate beam design help” with some information about this.

Garth Dreger PE
AZ Phoenix area

 

[HSIII]

I always wondered about the true definition of "flitch". I've heard it described both as wood sandwiching a steel plate and steel plate sandwiching wood.

In your professional opinion, is there truly a difference?

Personally, I don't think so, since the wood is depending on the steel plate in either scenario for added strength and moment of inertia.

 

[sema79]

I am attaching a pdf on flitch beam design that may be of some help to you.

 

[rittz]

An English dictionary says "One of several planks secured together to form a single beam"
j

 

[Brad805]

Rittz, I think you should thank these guys for being nice to you during the christmas season. This is a third year engineering question, and I am a little concerned.

Brad

 

[msquared48]

Third year? Heck... I was stitching beams together at 10 for treehouses!

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

 

[a2mfk]

Mike- you built tree houses with steel plates? SWEET! Wish I grew up in your neighborhood, we could have collaborated.

 

[beaming]

I think that "flitch" derives from "fleche", or feather. The flitch is the thin or thinner thing.

I would not be confident that an outside plate on an inside wood beam would be prevented from wrinkling unless I did a bunch of work about wrinkling or buckling.