Sample Calculations for Timber Beam

[TheScullster]

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

[Peter Crosland]

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

Peter Crosland

[Peter Scott]

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

Another option is:

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

Peter Scott

[TheScullster]

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

[Peter Crosland]

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

[Rick]

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

[The Natural Philosopher]

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.

[John Rumm]

out on the beams I have tried with it.

I would recommend Superbeam (demo here

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)

[John Rumm]

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: