Structural Calculations

[sunrise26]

Can anyone recommend an easy to use and understand beam/joist/rafter length calculator for a non-structural engineer type house designer? I want to know that the structural design is not over done or more important under designed from a structural perspective.

[jack krantz]

David,
I have a program, Beam Check that I got from http://www.berryvalesoftware.com/ that is quite easy to learn & seems to work well.

Jack Krantz
Krantz Builders

[HumbleChief]

David you mention a 'beam/joist/rafter "length" calculator and then say you are interested in structural concerns. I may have this wrong but it seems one request might require a beam/joist/rafter calculator to figure compound angles and bird's mouths and 'lengths' etc. where the other request as far as structural integrity and sizing the joists/rafters properly might require a simplre span table that you can probably get from your city or county?

Those span tables will let you know, for instance, how far a 2 x 6 can 'span' as a joist or as a rafter, with drywall below, plaster below etc. Might be all you need to figure the proper sized lumber and the only reliable way to get those sizes to match your municipality exact needs.

Hope that helps.

Larry

Originally posted by sunrise26
Can anyone recommend an easy to use and understand beam/joist/rafter length calculator for a non-structural engineer type house designer? I want to know that the structural design is not over done or more important under designed from a structural perspective.

[sunrise26]

Thanks Jack and Larry! Both suggestions are excellent. I'm just looking for something that's simple and easy to use!

BTW, Chief is an awesome program and this email site is an immense help!!! My thanks to all who share their knowledge.

[James Eggert]

I was going to use BeamCheck(from Berryvale) to replace an old beam program but I ended up purchasing StrucCalc because of extra features that I needed, such as concrete footing and pier sizes, steel beams, and a little more in the I-joist and LVL capabilities.

If I didn't need those extras, I would have purchased BeamCheck.

Don't forget also that Berryvale has EasyRafters, which calculates the rafter lengths and prepares a cut schedule for framing.

[James Eggert]

Sorry, forgot the link

www.strucalc.com

very powerful next step in software capabilities

[WHirsch]

Try the free, online span calculator at http://www.awc.org/calculators/span/...rcalcstyle.asp

or download WWPA's free lumber design suite at http://www.wwpa.org/techguide/suite.htm for a slightly more functional version.

StrucCalc is great, but not much use if you don't know how or what to input.

[James Eggert]

Warren

That's really the whole point, none of these programs are much use if....."you don't know how or what to input."

Just like a CAD program, it takes a little training and common sense to use what is available to us!

[WHirsch]

I'm afraid that I disagree. The "how" is learning curve, just as in any cad program... but the "what" is something that requires considerably more than "a little training". It is quite easy to produce absolutely erroneous output from StrucCalc or other similar programs. I see it happen all the time (I'm not referring to simple joist and rafter span calculations).

Please do not misunderstand me. My post was in response to sunrise 26, who was looking for "an easy to use and understand beam/joist/rafter length calculator for a non-structural engineer type house designer". If you know what you are doing, then a program like StucCalc is a useful tool. If you don't really know what you are doing, then you can be very dangerous with this kind of software.

[sunrise26]

Warren, I totally agree with your statement;

"If you know what you are doing, then a program like StucCalc is a useful tool. If you don't really know what you are doing, then you can be very dangerous with this kind of software."

and this is why I posted the thread in the beginning. CA is an incredible program allowing you to be very creative in the design arena, however, one must be cautious and apply a certain amount of common sense when observing what the program has created and being able to actually apply the design to the real world. Especially in the area of framing where today architects and home designers are creating large open area rooms. This is where paying attention to span charts, as previously mentioned, and loading factors of the design should raise serious concerns for the building designer. If one is not a structural engineer you should proceed with a great deal caution and determine ways to certify that your design is safe.

If anyone knows of any additional user friendly and conservative minded methods/programs for doing a structural check on a residential design I would like to learn of them. Or, if one can verify the ease of use of the few programs which have been mention I would like to here of that also.

[glowitz]

Originally posted by sunrise26
Can anyone recommend an easy to use and understand beam/joist/rafter length calculator for a non-structural engineer type house designer? I want to know that the structural design is not over done or more important under designed from a structural perspective.

BeamChek is among the easiest to use beam and column design software applications I've found on the market in the under $200 range. It's available on CD-ROM (MS-Windows) at http://www.builderswebsource.com/sof...e.beamchek.htm

However, anyone contemplating sizing of structural members without knowledge of engineering and loading principles is advised to think twice before doing your own calculations. No matter which program you use, one minor error in your assumptions or data entry could result in a structural hazard. However, if you know what you're doing and/or your plans will be checked by a licensed engineer anyway, then programs like BeamChek are a good value. They're also good for estimating and job costing purposes.

[Allen42acj]

I have Easy Rafter.
It works great for doing odd pitches=4 3/4- 12
It wont tell you how big they have to be ,but a good program.
You can get a 30 day trial of the full program from Berryvale .
If I would only remember to bring the numbers with me when doing the rafter patterns. At least I still remember the old ways(framing sq. or the book with charts)Don't remember the the sq root way and can't spell hypotinose anyway.
Allen Colburn

[frwillia]

Originally posted by sunrise26
Can anyone recommend an easy to use and understand beam/joist/rafter length calculator for a non-structural engineer type house designer? I want to know that the structural design is not over done or more important under designed from a structural perspective.

You have gotten a lot of good input. And if you already know all this, please forgive me for stating the obvious, but sometimes its a good idea to do so.

The key to using any of the vertical load SW, and in fact to any successful structural design, is being able to properly estimate the loads, and understand the load path, so you can give the right input to the SW. GIGO (garbage in = garbage out) is the truth! Lateral loads (wind, which always applies, and seismic, which may be significant) are a whole different matter for another day

Full disclosure: I'm an engineer, but not a Civil or Structural engineer. I've had the classes in structural analysis that show up in most Architectural cirriculiums (about 40 years ago) but not nearly as many as a civil engineer. With that background, in my opinion:

The best thing about BeamCHEK is the manual. Download it and read it (free). It's introductory description of load paths is as good as I've seen for residential building. It isn't anythying like complete, but its a very understandable start and will let you know what you don't know - always a good start.

The absolute best analysis programs I've found for for wood and engineered lumber products are free. TJ-Beam and BC-CALC are available free from TrusJoist and Boise Cascade repsectively. They are both totally excellent programs and completely outclass StrucCALC and BeamCHEK for wood products in a number of ways, including number of spans in a continuous beam, and having the "right" properties for the propritary engineered lumber products, like I-joists and TimberStrand PSL, for example.

Since we use mostly TrusJoist products in this area, I use TJ-Beam a lot. Highly recommended. And as I said, its free. They are both maintained by the publishers, and updated regularely with new products, etc.

That said, neither BC-CALC or TJ-Beam do steel, and nearly all the houses we build have steel beams under the first floor. For steel I-beams, other steel members, columns, posts, etc. StrucCALC is adequate. It has some nice autosizing features. After entering the geometry and loads, you can select a range of "W" sizes - Say W8 through W12 and it will tell you the minimum weight per foot for each size that is adequate for the geometry and load specified. We usually go with the size that gives us the lightest weight per foot (usually the lowest cost) and then upsize it one "weight" step.

Even with the best SW, there are reference books that are invaluable. The following are "must have" references:

The best source for loads estimation rules is ASCE7-02 - it is the bible upon which the ICC, and many other code sets are based.

The most understandable sawn lumber sizing guides are the WFCM and WFCM commentary (really excellent) - which are also referenced as acceptable and the basis for the tables in the ICC code sets. The NDS is also referenced in the ICC code sets and is excellent, especially for shear panel strengths, and includes the very useful fastener load capabilities in verious species of wood.

The best book I've found on wood structural design is "Design of Wood Structures - ASD" by Breyer, Fridley, Pollock, and Cobeen. I learned about it because it was my youngest daughters text book for that class (which was taught by Donald Bryer himself) when she was at Cal Poly Pomona (Civil Engineering Graduate). I borrowed her copy for a week and then ordered my own (fifth edition). I love that book! It sits on the desk here full time. I started at chapter 1 and worked my way through it to the back. I only had to ask my daughter a couple of questions on the way (she got an "A" from Breyer) - its really beyond excellent.

Finally, you must have a set of the local building codes in your office. The codes also frequently have local variences that are increases in some requirements, so you need to have a copy of those as well.

Fitch

[Allen42acj]

Thanks Fitch
I just got that book on Ebay"Design of Wood Structures
Only $8.00 with S&H.
The manual for beam check,is that with the demo download?
I couldn't see just the manual.
Thanks again.
I am trying a few beam softwares,so far like BC CAL the best,you get red warnings if they are to small.
Not ready to put my name on anything,the engineers always come up with biggers ones than I get Must be the difference of putting your name on something or not.
Allen Colburn

[frwillia]

Originally posted by Allen42acj
Thanks Fitch
I just got that book on Ebay"Design of Wood Structures
Only $8.00 with S&H.
The manual for beam check,is that with the demo download?

It might be - I don't remember for sure.

[/B]I am trying a few beam softwares,so far like BC CAL the best,you get red warnings if they are to small.[/B]

Same in TJ-Beam. They also tell you where it fails so you can make corrective design changes.

[/B]Not ready to put my name on anything,the engineers always come up with biggers ones than I get Must be the difference of putting your name on something or not.
Allen Colburn [/B]

When you get a different answer - that is a learning opportunity. Most important, find out what loads the engineer used, and why. If you have a good engineer, he/she will be willing to spend 5 minutes to review their results with you, show you the loads used, where they came from and provide you a copy of their analysis report. If he/she doesn't document their work - get a different engineer!

Fitch