Classical Truss Solution 1

[driftLimiter]

Here is a cool snip I found from a real Design. Credit is to John K Minasian, Circa 1950.
I couldn't help but share it here its just so pristine. Theres a bunch more drawings and details to go along with this calc the hand drawings are very clean other than some eraser and smudge marks.

 

[KootK]

That is cool, thanks for sharing dL. I bought some books on graphical analysis of trusses meaning to teach that to myself. But, alas, even I can't waste that much non-billable time...

 

[driftLimiter]

I'd like to know the name of some of those books. This got me thinking maybe graphical solutions could offer some efficiencies for computer solutions (maybe not)

 

[dik]

That's how we used to design trusses, back 50 years ago... Cremona diagrams... parallel rule and adjustable triangle... that was a time.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[rb1957]

yeah ... scaled drawing of force polygons. a different age.

Much like the NASA "calculators" could draw on different solutions to orbital mechanics mathematics that the engineers hadn't learnt (or couldn't remember or apply).

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[KootK]

Based on skims, I like the first much better than the 2nd, both in terms of print quality and content. Don't let the goofy cover of the first one put you off. It's just a dust jacket and a reprint of what was once, I'm sure, a perfectly respectable publication.

 

[dik]

I still remember Arnold Crosier (an old, great, and deceased Canadian engineer) showing me how to draw a parabola using a straight edge... 50+ years back.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[driftLimiter]

Sometimes it seems like computers are both a tool and a hinderance to our profession. Nowadays the truss can be solved and the results printed in a matter of minutes, our client base knows this, and now expects all of our work products on an accelerated timeframe. Being able to rush through calculations tends to make people want to rush through drawings and other documentation. I like to see work like this because it reminds me that care and pride should go into everything we do.

 

[dik]

a mouthful, DL...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[driftLimiter]

I know I'm preaching to the choir dik.

 

[ALK2415]

Only for the Canadian Engineers
1920

https://drive.google.com/file/d/1cI_xF29iZwf7Q47VJgBjaq1VEkw49_UF/view?usp=sharing

2020

https://drive.google.com/file/d/1xRfXlAs9nLd6k8hu4U9_dISSbBwlZaCz/view?usp=sharing

 

[271828]

Sometimes it seems like computers are both a tool and a hinderance to our profession. ...

I think this is right overall.

There's the element you mentioned. Things are too easy to change, so it's more common to get wrong or incomplete drawings, and the other guy thinks you can change your stuff to match by pressing "Run" again.

There's another element, and that's the power of focus. When I do something manually, away from my computer, I get tired a lot faster. That's because I was REALLY focusing that whole time. There's no eng-tips.com, email, FB, or any other distraction to let my brain take the foot off the gas pedal. I designed building for about two years before I got my first computer, and I'm pretty sure I was faster before, with just my paper, pencil, eraser, straight-edge, manuals, and calculator.

 

[EdStainless]

I was a draftsman for a structural back in the late 70's.
This is how we did it.
In our case mostly wood trusses. (the owners PhD was on the holding strength of nail plates)
We would generate one drawing for an entire family of trusses.
And we had thousands of such drawings.
And even with all of those we did a new one every week.
I couldn't do it now to save my life.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[dik]

I think the only effect computers have had on structural engineering is we're being paid less and less for greater liability.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[hokie66]

dik,

We always called them Maxwell diagrams. Maxwell was a British physicist. Cremona was an Italian mathematician.

https://encyclopedia2.thefreedictionary.com/Maxwell-Cremona+Diagram

 

[GregLocock]

The idea of labelling the spaces between the members to construct a Maxwell diagram was called Bow's notation at uni, they are such pretty things I used to sketch them out for fun.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[dik]

Yup... thanks. Didn't know about Maxwell... did dozens of them and used them for basis for indeterminate trusses. As I said... those were the days. Even had a Chinese engineer at Crosier's office that used an abacus instead of a sliderule... you could just hear him rattling the little beads. A whole different time period with 'gentlemen' engineers... not at all like today.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Tomfh]

Beautiful. Puts us all to shame.

 

[wrantler]

This is very intriguing. I would like to learn this method to validate a truss rehab project I am on...on my own time of course.

 

[dik]

You can actually use a CAD program to draw the force diagrams. It's a lot easier than using a parallel rule and an engineering scale.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik