How to build wood tower ?

[quatumrulesoverall]

Hi guys, could anyone of you suggest how to build a wood tower (probably balsa) and glue in oder to be as much light and strong as possible? Which structure should I use to support as heavy weight as possible?

[ronthepon]

Use arches to support the major reigions of your frame.

[quatumrulesoverall]

Originally Posted by ronthepon

Use arches to support the major reigions of your frame.

Great then, but how could I build arches from straight wood ?

[HydrogenBond]

Besides arches, the triangle is a very strong shape. Once the apexes are pinnned or glued, the wood has to buckle before the shape distorts. Making support beams out of a lot of little wood triangles leads to a very strong shape, i.e., roof trusses, with the load distributed over more material.

The compression strength can be further increased with lamination. This means plywood and maybe I-beams. These will increase compression strength for the same amount of wood. Try to combine plywood, I-beams and triangles.

[eric l]

Originally Posted by quatumrulesoverall

Great then, but how could I build arches from straight wood ?

You can bend wood after steaming it. If it is something like a scale model that you want to build, you can steam the wood in a pressure cooker with a very little amount of water, and a kind of grid above it to support your sticks.

If it is a full size tower you want to build, start with Wikipedia for info on trusses : Truss - Wikipedia, the free encyclopedia

[ErlyRisa]

actually ''Not'' steaming the wood when bending, and bendind it so that it in-effect becomes the spring... will take a greater load for less weight than any other structure... you could distribute the load amongst many 'springs' allong the height of the structure... just watch it you don't go over the maxload rating!

PS... this is the concept used in bridge building.... forces are 'pre-tensioned' throughout the structure and directed to an 'immovable' anchor.

OH PPS ... the Galelian Arc.. is the most 'light vs force' arc that can be used.

[Turtle]

Combine these two good classes of bridging ideas and support your bent arch with triangular trussing. No matter what form you use, make your cuts as precise as possible, as glue filled gaps are weak.

[ErlyRisa]

another good tip...and a bit of a challenge

Dont cheat with glue joins at all.

Medievil techinques, of split pins and tennoning will be infinitly stronger than glue... especially so becuase wood 'changes'.

[CraigD]

Originally Posted by quatumrulesoverall

Hi guys, could anyone of you suggest how to build a wood tower (probably balsa) and glue in oder to be as much light and strong as possible?

…

Originally Posted by Turtle

Combine these two good classes of bridging ideas and support your bent arch with triangular trussing. No matter what form you use, make your cuts as precise as possible, as glue filled gaps are weak.

This thread seemed to swerve quickly from building a tower to building a bridge – two very different design challenges.

Assuming the tower must support a rigid object at least as wide and deep as it – such as a bricks on a sturdy wood board (pallet) – the challenge is to assure that one or more (wood) columns bear the compression force without flexing and buckling. Since it must prevent the pallet from tipping, a design with at least 3 columns is suggested, with light cross-braces to prevent flexing and shifting. The closer together the columns are, the easier it will be to have effective cross-bracing. The wider, the better it will resist tipping of the pallet.

A lot of variable are involved, so making several prototypes might be a good approach. Keep in mind that its failure mode is likely to be flexing and buckling of the columns, not their failure due to exceeding the wood’s compression strength, so be as precise as possible in assuring the wood columns are straight.

There are, of course, alternatives to the direct approach I describe above. Intentionally bowing the wood, then attempting to manage its obvious flexing, is one, though unless you are allowed to use a material with good tensional strength, such as wire or thread, I think the previous approach would be better.

PS: Moved from math and physics to projects & homework forum, because it is.

[Turtle]

Originally Posted by CraigD

…

This thread seemed to swerve quickly from building a tower to building a bridge – two very different design challenges.

I knew I should have left the 'e' in 'bridgeing'. I was not referring to a bridge, but rather structural components referred to as 'bridgeing'. My bad for the jargon.