Beam Calculator

[Medeek]

I've recently started doing a lot more residential structural engineering for local clients and the first thing that I realized was that I was lacking a good beam calculator.   I do have a number of spreadsheet calculators but I've found them hard to program and once I do have them programmed any changes are tedious since the equations in Excel are hard to follow (I know VBA can be used in macros). 

To that end, I've started working on a web based beam calculator that will be able to handle sawn lumber, glulam and structural composite lumber, programmed in Perl/HTML/Javascript.

It is still a work in progress however the "sawn lumber" option should now give a full output.  I will be adding in the PDF output as time allows and also the other beam types listed above. 

Currently the selection of lumber species is also somewhat limited however adding new species is simply a matter of adding the appropriate values from the NDS into the database.  If there is a particular species or grade you would like added please advise.

Any feedback, positive or negative is always appreciated.

The beam calculator is currently located here:  http://design.medeek.com/resources/beam/beam_calculator.pl

[Don_P]

  Very nice!
These might provide more grist for the mill, they're all simple javascript, feel free if any of it is of use;
http://www.timbertoolbox.com/Calcs/beamindex.html

The awc might be interested, I've asked them to put some beam calcs up to supplement their joist and rafter calcs.

[Medeek]

Thank-you for the links.  I will probably use them as a means for checking my own numbers.  With something like this I find it is very easy to mix up the units or have a typo in the equations which of course turn the results into complete garbage.  Most of my time on this was actually spent debugging the code and equations.

Most of my spreadsheet calculators are very compact in their presentation, which is fine for structural reports for building departments however with this online calculator I wanted to break it down as clearly as possible so that literally every step of the engineering of the beam is explained.  Hopefully I've accomplished this but more notation and explanatory text may be in order.

[John Raabe]

Good resource this!

[Medeek]

The PDF report generator for Sawn Lumber beams is now live. 

I haven't completely put the calculator through exhaustive testing yet but nearly as I can tell it is producing correct results.

To Do List:

1.) Add more common load cases as given in the AWC Design Aid #6
2.) Add the rest of the sawn lumber species from the Table 4A NDS Supplement
3.) Complete the Glulam and SCL options.
4.) Add new features as requested.

[Don_P]

The reason I made my calcs originally was to be able to use table 4D and timbers from my sawmill at actual sawn dimensions. A niche to be sure but might be worth considering.

[Medeek]

Ok, I will add this to the list.  Another option for timbers 5x5 and larger.  Table 1B has the standard dressed sizes however I think what you are suggesting is that I make this user configurable so any size can be entered (ie. rough sawn beams).

[Don_P]

Exactly 

Another one for the back burner is a calc that allows multiple loading, for instance a uniformly loaded beam that has one or more additional point loads located anywhere along the length. Or to use an example from the last week or so here, a uniformly loaded floor joist overhanging supports at both ends with point loads from the walls and roof above on the ends.

[Medeek]

I'm working on adding these three load conditions:







Note, that any one of the applied forces can be input as zero so the actual load cases are quite large with these additional three configurations.

These 3 load cases will encompass the following load cases from the AWC Design Aid #6:

18,20,21, 22, 27,28, 29,30, 31,32

the current load cases cover the AWC load case 1 and 7.

The different span lengths must be greater than zero.  The bearing lengths will be assumed the same for all supports.

[Don_P]

Very cool!
For anyone following, AWC's Design Aid #6 giving basic beam formulas for different load/support conditions is available as a free download here;
http://www.awc.org/publications/DA/index.php

What Medeek is doing is really neat, this would be combining multiple load types on different support configurations. This will give better answers to some pretty common problems.

[Medeek]

Glulam beam option is now working as well as its PDF report.  I haven't entered many glulam beams from Table 5A yet but I think the most commonly used types are listed for now.  The nuts and bolts are there so now its just a matter of entering some tabulated data for all of the stress classes/combos.

I've tested the glulam option against a number of sample problems from "Design of Wood Structures ASD/LRFD", so far it is giving the correct answers, however further testing will be required.

I do have a few issues with the drop down menus not sticking when one hits the back button on their browser, I'm still working on this.