Sample Calculations for Timber Beam
 

Hi all

Does anyone have any sample calculations or links for timber beams please?
This will be built into wall at each end - supported on internal leaf.
It will take the weight of ceiling and joists only, with whatever imposed
load is applicable for a loft space.
I am particularly interested in the timber grade selection. Not sure what
variety of wood is generally used and therefore allowable stresses etc

Thanks in anticipation

Phil

Building control will want to see proper calculations for which you will
probably need a structural engineer to do for you.

Peter Crosland

"TheScullster" phil-at-dropthespam.com wrote in message
...
Hi all

Does anyone have any sample calculations or links for timber beams please?
This will be built into wall at each end - supported on internal leaf.
It will take the weight of ceiling and joists only, with whatever imposed
load is applicable for a loft space.
I am particularly interested in the timber grade selection. Not sure what
variety of wood is generally used and therefore allowable stresses etc

You could try:
http://loadsoft.narod.ru/education_a...ineering/2inde
x.html

There are several beam programs here. Don't know enough about it to
comment on how good they are.


Another option is:
http://www.sda.co.uk/sbwdemo.htm

You could perhaps do the calcs with the non-printing demo to
see if it does what you want (or screenshots)

Peter Scott

Thanks Peter

Yes I understand this, but having done a HNC in civil/structural engineering
I was going to do them myself.
If I get enough pointers or references and insist that BC checks them
carefully (ie earn their money) then I may just save myself a few squids and
excercise the little grey cells into the bargain.

Phil

Fair comment Phil. Good luck with the project. I am sure there must be some
free/shareware software out there to ease the effort.

Peter Crosland

On Fri, 1 Apr 2005 17:36:52 +0100, "Peter Crosland"
wrote:

Fair comment Phil. Good luck with the project. I am sure there must be some
free/shareware software out there to ease the effort.

Peter Crosland




Somone here posted this when I needed it a while back ......

http://www.woodbin.com/calcs/

Rick

TheScullster wrote:

Thanks Peter

Yes I understand this, but having done a HNC in civil/structural engineering
I was going to do them myself.
If I get enough pointers or references and insist that BC checks them
carefully (ie earn their money) then I may just save myself a few squids and
excercise the little grey cells into the bargain.

Phil


The only thimng they worry about is acceptable deflection, and there are
tables of spans/weights/sizes somewhere about that are 'to spec' fo the
sort of cardboard-on-steroids that is called structural timber at the BM's.

actual breaking strain is never an issue - its well over the size where
the thing has sagged unacceptably.

Since the cost of beams is way below the price of a chippie to install
them, things tend to be remarkably over-engineered anyway.

Rick wrote:

Somone here posted this when I needed it a while back ......

http://www.woodbin.com/calcs/

I would avoid that one - its answers seem to be at least a factor of 2
out on the beams I have tried with it.

I would recommend Superbeam (demo here http://www.sda.co.uk/sbw.htm) on
the grounds that it is very good, and also seems to be the program used
by many BCOs anyway so you will be giving them stuff in a familiar format)


--
Cheers,

John.

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The Natural Philosopher wrote:

The only thimng they worry about is acceptable deflection, and there are
tables of spans/weights/sizes somewhere about that are 'to spec' fo the
sort of cardboard-on-steroids that is called structural timber at the BM's.

The usual guide is:

max deflection = 0.003 * Length

(IIRC there is a cutoff limit of 14mm max deflection as well)

I find this book is stuffed full of handy data that can often give you a
clue as to an appropriate starting point:

http://www.amazon.co.uk/exec/obidos/...ternodeltdcomp



--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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\================================================= ================/