Interaction Diagrams For Wood Stud Walls 8

[KootK]

So I decided that I no longer wanted to be beholden to Woodworks etc and I would make my own stud wall MathCAD sheet. Go me. I wanted it done differently than what I see most folks do though. I wanted to generate interaction diagrams so that, for given project, I could just generate the diagrams for the handful of wall types that I'll use and then pick values from the graphs as needed. The graphs below do this I think. Each line is a different duration factor (0.9,1,1.25,1.6). They are for 2x4 stud grade 92.625" long; wind (psf) on the x-axis and axial (plf) on the y-ais. I've attached a printout of the entire worksheet for the ambitious.

I've spot checked some results and they seem to be okay. What's bothering me is how straight these curves are. The only action is at the top left in the first diagram where things get curvy with low levels of wind pressure. If you include minimum axial eccentricity of d/6 like software often does, even that goes away. That's what's shown in the second graph below.

So my question is this: does anybody have enough experience with wood stud wall interaction diagrams that they could confirm or deny if the results I'm getting look nuts. Considering how straight the lines are, I would have thought that NDS would just simplify the equations to suit. Frankly, if it's this linear, I feel pretty silly for even going to the trouble of making this spreadsheet.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[dik]

As far as I know, this is now the best wood stud wall design tool available on planet earth, P4P or otherwise.

Give him a star... I can only give him one...

Dik

 

[Celt83]

I needed to make back hand checks on the user data easier so overhauled the results table, maybe I'm satisfied with it for now??

enhancement:

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[Celt83]

one more small change - was killing me that OK wasn't green and NG wasn't red

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[Celt83]

correction:
-User Loads - Self Weight was being considered as an eccentric load when eccentricity was considered, it is rational to assume that self weight would apply concentric to the wall panel and not eccentric.

enhancement:
-User Loads - Spacing Optimization - first pass check of 24" o.c. will now occur before the routine enters its loop. 24" is the upper bound for Cr=1.15 to still apply.

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[Celt83]

additions:
-can now export the user load results to a csv file

the main export is now a single csv file in lieu of a csv of the nds table and text file of the results

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[dik]

Haven't run this version... can you print this to a file and use a pdf printer driver?'. I generally run my design info on my laptop and create printed files using Doropdf as a printer and save my *.pdf files to the project file on the company server.

Dik

 

[Celt83]

CSV = comma separated file you can open it directly with excel or libre office and the output is preformatted so items are separated into cells, I typical try to setup it so all numerical values are in their own cell.

Or are you asking if it's possible to get a pdf directly as output from the program? Short answer is yes, long answer is I've barely read the documentation on the syntax for the report module, reportlab, from what i have read it looks like it can be like writing another program on its own.

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[dik]

I was aware of comma separated variables... not actually part of your program. If the output can be printed, there are external 'driver' files that can print to *.pdf... I'll attach a *.pdf printed directly from one of my spreadsheets...

The attached file would appear the same if printed to a colour printer or a *.pdf. I save the *.pdf to my project notes file. Printed directly from excel. I've installed Doropdf on my computer and when printing it comes up as a printer type and just select it and let Windows do the work.

Dik

 

[Celt83]

hmm....I keep hitting a deadend in my search efforts on executing a print job from within python.

I think the options right now are:
-Learn ReportLab and get a direct pdf output from my program
-Write out an HTML+css fileset for the exports, then convert that html to PDF - there are a couple modules that seem to handle this
-use Matplotlib to plot a blank chart and add text by coordinates - probably a last resort

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[dik]

As long as you can put out a formatted output to a printer, Doropdf can create a pdf file. It runs like a printer driver and you simply select it as the printer, as attached. No need for other plug-ins, or, special coding.

added... when I'm working on a project, I have hundreds of spreadsheets that I use for different tasks. I enter the project data and run the sheet and print it to a pdf. I don't usually leave a copy of my spreadsheet on the company server. I usually use my laptop rather than the company server and copy my pdf created on the laptop to the sub-directory on the company server at the end of the day/project. My laptop is a lot faster... I can be using my laptop before the company desktop has even reached the logon screen.

Dik

 

[Celt83]

Best I can do at my current skill level is output the csv file for the end user to open in excel and add their own color formatting as desired before printing from within excel.

Printing to a printer, physical or virtual, from within python doesn't appear to be a very easy task.

I work pretty much the same way you do I much prefer a PDF of the output to store on the office server in our calculation folders.

KootK:
count me in for collaboration on future programming endeavors.

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[dik]

Celt83:

The comment was not to be a criticism, but, possibly a manner in producing an easy printout of data without having to jump through hoops to get it. I use this often for printouts as noted in my excel example.

What you've done is incredible and has taken a lot of effort, and thanks for posting your source code.

Dik

 

[XR250]

I have a program that is too old to print so I screenshot the outputs directly into a PDF. Not sure if Windows does this as I do most of my work on a Mac.

 

[Celt83]

Dik:
No worries wasn't taking what you were saying as criticism. The output side of things is something I keep reading up on, right now you could right click on any of those files and print to your or any PDF printer it'll just be plain text. The hard part, as far as I know, is that "formatted" word for anything beyond new lines and spaces things get a bit tricky.

I kind of have this to a point that I'm ok with it and not seeing anything that immediately jumps out and bugs me. If anybody finds anything they'd like added/corrected please let me know. Easiest method would be to file an issue on github to make it a little easier to track please put [Wood Stud Wall] in the issue title. If you could also give it label that would be helpful too in prioritizing calculation corrections over feature requests.

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[sticksandtriangles]

I will add mine to the mix.

Mathcad file attached well for reference.

Thanks for pushing me to do this as well. These are good little exercises in coding and wood design.

 

[sticksandtriangles]

PDF attached as well.

Kootk, I refrained from looking at your mathcad sheet until I made mine. We took pretty different approaches in mathcad. Im not a huge function fan for some reason.

 

[dik]

sticksandtriangles:

Functions are really useful at times... might try a few of them to get into the use of them. I'll take a gander at your use of arrays... looks good.

My new calculator, has incredible function capability, but unfortunately, you cannot call a function from a function, subroutine, or a program... cut the ability off at the knees and greatly reduces programmability.

Dik

 

[Celt83]

nice

Looked thru your PDF Sticks couple questions:
CL your calculating a value here but the bracing assumption for the stud wall sheathing satisfies the criteria to consider a CL of 1.0
Looks like you've got a second interaction check of (fc/Fce2)^2 + (fb/Fbe)^2 any reason or reference for doing this interaction?

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[sticksandtriangles]

Celt,

I am not a wood person, so I am having this sheet reviewed our wood people as well (they seem to like it so far).
I appreciate the 2nd set of eyes.
In my beam bending design where I calc'd Cl, I was assuming that under a suction load, compression would develop on a face that I did not know if it would have sheathing. Therefore I calc'd Cl. Is this atypical in wood design assumptions? I counted on the sheathing to brace the stud in the column calculations for out of plane buckling.

With regards to your second question, "(fc/Fc)^2 + (fb/Fb)^2 any reason or reference for doing this interaction?"
This was actually a typo of equation 3.9-4 and me getting lazy (not checked in my current setup). Equation should be (fc/FcE2) + (fb1/Fb)^2 < 1.0. Does this equation control in your experience? I might need to add it to the sheet if so.

Thanks,
S&T

 

[Celt83]

Got it, think that can be a fair assumption.

Looks like they added 3.9-4 in NDS 2012 wasn't aware of that one, seems unlikely to control given the fully braced assumption for the short face of the stud, doesn't hurt to check it though.

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering