Medeek Engineering

[Medeek]

I have posted frequently on the various extensions that I create within SketchUp to augment and automate SketchUp.  Some of this geometry can also be brought into Chief where the Chief user does not want to be bothered with modeling intricate timber trusses etc...

I am also working on various engineering tools that will work directly inside of SketchUp.  The tools will be useful for the residential designer and architect to run quick numbers on various things like posts and beams.  I am currently focused on developing a beam analysis tool that will facilitate these sorts of engineering tasks.  At some point I may also offering engineering consulting for an additional fee, but that is yet to be determined.

Here is the latest status on the development of the upcoming beam engineering tool:

 

I am currently working on a beam analysis tool for analyzing (wood) beams within my Wall extension. It's taken a couple weeks to cobble together the matrix analysis engine but it is slowing emerging.

Now that I have the shear, moment, slope and deflections algorithms in place for point loads it is just a matter of algebraically adding multiple loads for more complex loading scenarios (ie. multiple loads and factored load cases). Here is a very simple example of two point loads applied to a two span beam. Note that self weight of the beam is not yet being considered:

I need to add some formatting logic into the top beam diagram to account for shorter spans so the dimensions don’t run into the supports as shown. This is why a lot of testing and debugging is necessary.

This beam engineering tool with its matrix analysis engine is probably the single most complicated piece of code I’ve ever written, it certainly rivals the truss calculator (2013) and the complex roof (2019) module. I will admit that I now freely use ChatGPT with some of my coding puzzles lately and surprisingly it even understands the context of what I’m coding and offers suggestions to improve the accuracy and efficiency of the engine itself.

The numerical integration (for the slope and deflection) was initially stymied by incorrect boundary condition constants and I had no easy way of analytically solving for them. At that point I was fully aware of the issue but I was stumped at how to arrive at the right solution. ChatGPT suggested a normalization algorithm which proved to be correct and was even an easy fix within the algorithm. It’s like having a really smart graduate student looking over your shoulder pointing out what your doing wrong and how to make it all better.
 

[Medeek]

I’ve been wanting to finish this beam calculator for some time now so I’m trying to dig deep and see if I can’t get it out the door, even if it only has the capabilities to handle wood (sawn lumber, glulam, SCL, I-Joist) beams and joists initially..

Unlike my previous web based beam calculator this new tool will be completely open ended, there will be no limit on the number of supports or loads one can assign. Each load can have up to six different load types (dead, live, live roof, snow, wind, or seismic) So in a sense it is a general solver or engine which makes it quite powerful and much more useful in my opinion.

The one other harsh reality with engineering though is that the code is always changing. I will need to continually update the tool as future revisions to the ASCE7 and NDS are released as applicable. I’ve noticed as I review various copies of the ASCE7 (2005 - 2022) that the load cases are continually changing, which I find a bit odd, you would think that after years of refining the code we would slowly arrive at suitable load combinations and stick with them. This constant flux is rather annoying to be perfectly honest, and makes me really question the powers that be and why they can’t iteratively arrive at a standard and eventually stick with it.

We all know how the (engineering) sausage is made. Why continually tweak the recipe? The technology and materials used in the building industry has not dramatically changed in my lifetime (50+ years). All of this continual tweaking and minor adjustments to the engineering code really does nothing to safety of the structure in my mind and simply adds to the cost of engineering since new software updates are required and additional training is imposed. Maybe the ASCE needs to keep itself relevant and the revenue from selling updated pricey copies of its signature standard (ASCE7) is a serious cash cow? I don’t know what the story is with all of this but I feel I need to rant a bit when I just shelled out $260.00 for a paperback book that I will only crack open once every few months at best.

 

Here is another screenshot of the calculator interface:

 

The graphics are generated using SVG within HTML. I'm formatting the HTML so it can easily be printed to a nicely formatted PDF, easier said than done.

 

 

[Medeek]

I am curious.  How do CA users currently do some quick engineering calcs for structural members in their models?  What sort of workflow is typical or maybe there is no specific or typical workflow?

[richoffan]

BeamChek 2024. Been around a long time. Inexpensive one time purchase. Constant updates. Does wood (many species) wet, repetitive member, Glulam, LVL Micros, Steel. Lets you set your own values Fb, Fc, E etc.  etc. And offers several variants to select on the calcs so you can see actual % shear, depth of deflection and so on. Does col., notches, hips, valleys.... Never let me down. Submit calcs to structural if necessary and PE just comes back with some options if we want to consider. If you could take the model, allow user introduced values (30PSF, 40PSF, linears on partitions , stone veneers, snow loads etc.) and have the model show loads, tributaries, points, reactions etc. in the model - Now that would be AMAZING!!

Edited August 30 by richoffan

[Joe_Carrick]

I use StruCalc.  It provides just about anything you can imagine and I can stamp/sign myself.

[Medeek]

First look at the shear and moment diagrams being generated by the report generator.  It took me most of yesterday and today to learn the ropes of Chart.js, an open source charting library for Javascript.  It's not perfect but it does seem to get the job done.  My only real issues with it is that I still can't figure out how to make it render to a higher resolution (300 dpi for printing purposes).  The sample below is a screenshot of the PDF that is printed from the HTML output.

 

 

 

I've used quite a few different beam checkers and software in the past.  I used to use Woodworks Sizer app and then switched to Forte and BCCalc.  I was disappointed when those last two switched from a desktop app to a web based app, but I'm sure they had their reasons.  My standard report will be quiet verbose but I can also see the need for a compact one page report, so I will probably be working on that as well in the near future.

Even though a lot of people think that only engineers use this type of software that is quite incorrect in my opinion.  Any designer or architect worth his salt should know enough about the basics so that they are able to quickly run the numbers for a beam, header, rafter or joist.  Knowing the ballpark specs of any of these members is crucial in many cases when putting together a design.

Edited August 31 by Medeek

[Medeek]

I am using the stiffness method per Ch. 15 of R.C. Hibbeler’s book, Structural Analysis. For intermediate loads between supports I use (FEM) fixed end moments. I’m actually still working on the matrix analysis piece. I’ve got point loads pretty much in place I’ve just got to implement distributed loads next. I suppose I could have it generate the entire polynomial for both shear and the moments since I am generating them for each applied load, it is probably just matter of using superposition on them as well.

Here is a first look at the ability to switch between various load cases for the deflection graph:

[Medeek]

First look at a combined point load and distributed load. I'm not exactly happy with the shear diagram where it makes the vertical jumps. I will need in to add in a correction factor (additional point) at each point load and internal support so that the shear is properly reported at those locations.

 

 

[Medeek]

Still putting out a few fires and bugs. I had a small bug in my conditionals where loads were symmetric (like the example below), but I've resolved that now. My next fix is the vertical jump issue(s) with the shear diagram. I have some ideas on how to address this, just need to test it and see if it is the solution. Here is a symmetric point load scenario and the deflections for the two load cases:

P1 = 500 lbs (D)
P2 = P3 = 100 lbs (D) 500 lbs (L)

 

 

[Medeek]

Overhanging beams with point loads now check out.  Once again ChatGPT to the rescue to help debug my syntax and even debug my actual algorithms.  This AI stuff is getting crazy good, sometimes it makes mistakes but then it is able to reason and catch itself, it's uncanny.

Now I just need to debug for uniform distributed loads on overhanging beams.  Then it is on to the actual engineering portion (AWC stuff for wood) and some final formatting of the PDF/HTML report.

I'm also not entirely satisfied with the clunkiness of the tools used to move and create the supports, some improvements on this end are needed.  A load/support copy tool would be really nice, rather than having to create completely new loads and supports from scratch.

[Medeek]

First look at partial UDLs with overhangs:

So with that I think the basic nuts and bolts of the matrix analysis engine is in place and functioning pretty much as expected. Of course it will probably be a few more days or even weeks before I am able to put out every little fire that may be burning undetected thus far, but we will see.

Now I will turn my attention to the following items on the todo list:

1.) Try to fix the truncation in the shear graph so that vertical jumps actually are vertical.
2.) Add in the standard engineering checks for wood beams (glulam, lumber, timber, LVL, SCL and PSL)
3.) Finish the formatting and layout of the HTML report. I may also include an option between a condensed report and a detailed report (or that may come later).

Things that are not specifically on the todo list but are interesting:

Add in fixed and partially fixed supports, currently every support is assumed pinned.
- Engineering for steel beams
- Trapezoidal distributed loads
- Moment loads

[Medeek]

Version 0.8.1 - 09.07.2025
- Developed the matrix analysis engine for the beam calculator using the stiffness method.
- Added a load diagram to the beam report.
- Added shear and moment graph to the beam report.
- Added a deflection graph to the beam report.

 

The engineering report is still not complete however by rolling this beta release I can allow potential users of this plugin the ability to test it out and assist in the debugging.  The plugin can be directly downloaded from this link:

 

http://design.medeek.com/calculator/sketchup/medeek_engineering_ext.rbz

[Medeek]

In the global settings I will be adding in the option to toggle on or off the text showing the loads and reactions in the load diagram:

As you can see it does have the potential to get a little busy but I think it would be useful to have this available as an option.

There will also be a table below the diagram showing the details for each load and each support, so the information is a bit redundant in my opinion.  Thoughts?

Edited September 8 by Medeek

[Medeek]

Version 0.8.2 - 09.09.2025

- Enabled loads and reactions (values) within the load diagram.

- Fixed a bug with end supports that are not centered on the start or end of the beam.

- Improved the formatting logic (SVG and HTML) for the load diagram.

[Medeek]

First look at the bearing calcs:

Looks like I still need to update the disclaimer at the bottom, I borrowed this from my previous beam calculator.

[Medeek]

Spent the last two days adding in some additional code so that the vertical jumps in the shear graph (at point loads and supports) are actually vertical. It was a bit more complicated than I originally bargained on but I think I finally have it figured out:

 

 

The code seems fairly robust but tomorrow I will throw the kitchen sink at it to see if I can find any weaknesses in the algorithm.

I have't been posting much lately but that is because I've had my head buried in the code.  Most of this engineering code is completely new (not my typical plugin stuff) so there is no refactoring old code or any other shortcuts I can take.  Some of the old beam calculator is relevant however since it was so limited in its application I'm kind of on my own with this new calculator.

[Medeek]

The vertical jumps now look at lot better. So far it seems pretty solid: