Wooden rectangular tank design

[Weaverofduart]

Im trying to design a rectangular tank.

Using the method in eugene what is name "pressure vessel handbook" ive got the formulas I need but the book is for steel and gives a max stress value of 13 tho or so (from memory). Can anyone tell me the value to use for wood? If I can work it out from the modulos of elasticity that would be handy because I can then look up the species, the moe and then calculate the max stress value.

Plan a is to design and build a box which will be lined.
Plan b would be a different design method than that specified in the PVH. Bassically the method in the PBH specifies minimum deflections of less than half the thickness of the plate. For plan b I,d like my plates to be hdpe supported by horizontal and vertical stiffeners. Rather than the plate deflection being the critical design factor it would be the shear stress of points where the hdpe plate is secured. Or in other words I don't care how much the hpde sheet bulges between the stiffeners as long as it doesn't rip where it is secured to the wooden stiffeners. I think this method would be cheaper to build but unfortunately I don't have the formulas to do the calcs.

Can anyone help?

 

[oldrunner]

Hire a structural engineer who has experience in timber design. Just plugging numbers into formulas that you might not understand might not work. Your biggest problem is going to be connections. Other problems may be moisture content in the wood, type of plywood (I assume) wall covering and so on.

Wood values are found in the NDS.

 

[chicopee]

If you use plywood, use marine plywood.
Also find a local engineer,of mechanical,civil,structural,tank or marine discipline.

 

[Weaverofduart]

Appreciate the need to understand what you are doing. Following the instructions in the PVHB I feel I could do the designs in steal but we have access to a lot of timber relatively cheaply. I really need to learn how to do these calculations myself. If I have to employ an appropriate engineer it will cost a fortune because of the number of calculations that I would be needing to do. If I had a firm idea of what we need then I could hand it to a structural engineer but we are working with so many possibilities that I really need to do it myself. Also I've found that if I do design calcs myself I can cater my designs to the materials that I have on hand.

Also what id the nds? Is that an american thing?

 

[oldrunner]

The NDS is the National Design Specification for Wood Construction and yes, it is a US code. The code is fairly straight forward except for terminology which you would have to learn.

My timber text book is "Design of Wood Structures" by Breyer, 6th edition. Older editions would probably also assist you as they wouldn't be as expensive.

Wood is not like steel, especially plywood. Strengths in the different directions are different. Connections are different - actually a small wood house is sometimes far complicated and difficult to design than a tilt-up concrete building.

I've copied some references from an earlier post that should be of value:

http://www.wooduniversity.org/

http://www.apawood.org/level_b.cfm?content=pub_main

"Wood As An Engineering Material"

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm

http://www.mcvicker.com/twd/gwdi97/page002.htm

"Plywood Design Fundamentals"

http://www.canply.org/pdf/main/plywood_designfund.pdf

In my college, I learned timber design in my junior year.

Good luck.

 

[Weaverofduart]

Well I've had some success and now have tables for spans up to 13'.