The vertical section is what give you strength, it's exponential while just putting them in parallel is linear. So if you laminate as a 2x12 with prober glue, it would be stronger than a a 4x6.

I am not sure of what you mean by laminated. If you mean laminated side by side, the glue resin is usually stiffer than wood fiber so it's a bit stronger. But stacked vertically wood is lot stronger.

If we take y as vertical and x as horizontal in my last example:

case 1: x =2 y=12

case 2: x =4 y=6

Both case have a cross section of 24, yet case 1 will resist a far greater load. A practical example of this is a sheet of paper. Flat it bend like noodle, if you put it vertically and roll it you can get a little book to stay on top.

We ate building a bridge it's 14 feet long 10 feet wide what is the best to use just for the framing part a solid piece of lumber say 6x6 or 8x8 14 feet long or is it better to glue 3 pcs of lumber together 14 feet long my friend seams to think its stronger to glue and nail 3 14 foot boards together and bail together which is better

Customer:replied 5 years ago.

Just for the spand is a solid piece of wood better than 3 pcs together glued and nailed which well be stronger and is there any difference in using either wood the solid or the glued and fasten together

Solid is not stronger than glued together if the length of all those piece is 14 feet long.

Glued together have some advantages, the wood will cost less, it's easier to transport and handle.

That said, like i told earlier, the real strength come from the vertical length of the piece. You can also add strength with the same amount of wood if you use an arch in the design.

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