CAST YOUR VOTE! The Great DIY Steel Joist Detailing Competition of 2022 - Win $250 USD 30

[KootK]

Things have been a little slow around here lately for my liking. In an attempt to liven things up, I'm attempting something experimental: an engineering contest with a cash prize of $150 USD. This is your chance to:

A) Earn yourself some KootBucks and;

B) Establish yourself as a GSEL (Goddam Structural Engineering Legend).

THE CHALLENGE

In the spirit of times, develop a scheme for the fabrication of a steel joist that would be fabricated on site rather than by a conventional joist supplier (Vulcraft, Canam, etc).

THE RULES

1) Include sketches or be forever disparaged.

2) Describe the benefits of your proposal as you see them.

3) Submissions will be accepted until midnight on June 5th, Pacific Time.

4) On June 6th, voting will commence.

5) Voting will close at midnight on June 12th, Pacific Time

5) Votes will be cast by way of members visiting the thread and writing a quick note to indicate their favorite scheme.

6) Votes will NOT be cast by way of giving out little purple stars. Give out all the little purple stars that you wish but none will be recorded as a formal vote.

7) Anyone may enter the contest and win the prize. However, you need to have received at least 9 little purple stars on this forum in the past in order to qualify as a judge and cast a vote that will be counted. I'm setting this restriction only as an attempt to prevent this thing from spiraling into some weird, spammy, cheating affair. Basically, if you're to be in charge of awarding the KootBucks, you need a reputation.

8) The prize will be awarded in the form of an Amazon eGift card. The winner will need to send their burner email address to my burner address or whatever. We're smart kids, we'll figure it out.

9) No prize will be awarded if there are not at least five entries to choose from, including my own.

10) If JAE shows up to judge, he can cast my vote along with his own.

May the best engineer win!

 

[KootK]

But first, you gotsta beat Bobby!

Advantages & generally clever aspects:

1) Only two steel cross sections used. Just order a bunch of angle and channel and go to town.

2) End product is basically a KCS / constant shear joist good for RTU's etc if necessary.

3) Vertical webs should make the thing easy to jig up on an assembly table.

4) Optional end block should be able to generate almost limitless rollover capacity (finally).

5) Joists should be decent for nesting / stacking on a truck.

6) Critical compression chord diagonals come together with the centroids well aligned.

7) Less critical tension chord diagonals are eccentric but:

a) the tension will tend to straighten them out and;

b) the verticals should help rectify this via relatively stiff, weak axis flexure.

8) Conventional deck attachment to double angle chords.

9) Simple, automatic spacing of chords during fabrication.

10) Clean look for exposed applications.

11) Flat faces of vertical channel webs will be easy to fasten bridging or strong backs to.

12) I'll think of something to make it an even dozen...

 

[Celt83]

But you know bigger.

I'm making a thing:

http://www.thestructuraltoolbox.com

(It's no Kootware and it will probably break but it's alive!)

 

[JStephen]

Post 1 seemed to be a "think outside the box" contest. Post 2 seems to be a "must fit into this specific box" requirement, tho.

 

[phamENG]

Post 1 seemed to be a "think outside the box" contest. Post 2 seems to be a "must fit into this specific box" requirement, tho.

Pretty sure post number 2 is KootK's submission to the contest. Nice us of Escher, though. If I ever expand and get an office, I'm putting this on my wall: Link

 

[canwesteng]

I'll take a crack at it, maybe just to see why I'm wrong. My approach will the unistrut of OWSJ. You ship three different pieces to site, cut to length, and bolt together. It's simple so non specialized labor can do it, less labour intensive than measuring, test fitting, and welding a joist together. I imagine some kind of design software would come with the pieces and let you spit out a joist with basic plans to follow.

Pros:
1. Easy to assemble on site with only an angle grinder and some wrenches.
2. Modular design can be used for various truss depths.
3. Software spits out basic plans after input from the engineer.
4. Speed holes. Lots of speed holes (sell the architect on it, maybe human scale speed holes or some other gibberish).
5. Scale testing of the pieces and connections can be done and the testing costs spread out over many tons of steel.
6. Tried to get rid of eccentricity in the truss nodes, at the cost of pretty deep chords.

Cons:
1. Material cost. It's a lot more steel weight since this is somewhat inefficient and it spends more time in the python getting holes cut, so more costs in fab.
2. I don't think the seat detail is great, but it is elegant, reusing the chord material with holes guaranteed to align.

 

[JStephen]

"Pretty sure post number 2 is KootK's submission to the contest."
Oops. Didn't read close enough. "Ooh, that's very different. Never mind!"- Emily Litella

 

[Enable]

Just to clarify when you say fabricated on-site do you mean without any pre-fab in any metal shop whatsoever (so stock lengths of 24/40' to site direct) or can it be a mix of pre-fab based on say a local misc metal fabricator's abilities / on-site?

Second clarification, instead of amazon cards would shipped cowboy hats be out of the question? Mine is a tad worn since I was last at the stampede and could use an update!

 

[kipfoot]

I propose a warren truss using WT top and bottom chords with double angle web members. I like that it's simple and flexible. It's quick to model and can be fabricated using what's available in the steel yard. The panel point spacing can vary for efficiency, but the work points align and the angles can be square cut and have plenty of room for welds. At the bearing put a plate on the end and you've approximated a wide flange.

 

[KootK]

Just to clarify when you say fabricated on-site do you mean without any pre-fab in any metal shop whatsoever (so stock lengths of 24/40' to site direct) or can it be a mix of pre-fab based on say a local misc metal fabricator's abilities / on-site?

Dang it... I struggled with how to simply yet accurately describe what I was looking for. And, clearly, I did not "stick the landing".

Some degree of prefabrication -- even total prefabrication -- is welcome. I am, in fact, very interested to hear ideas from our contingent of steel fabricators: you, Dr.Z, CANPRO, Veer007, and the like.

Perhaps the easiest way to describe what I'm going for here is to describe what I don't want. What I don't want is your stock joist design that would be pre-fabricated en-masse by a joist supplier who considers joist supply to be their wheelhouse. The name of the game here is coming up with alternatives to such joists in response to the current, limited availability of such products. That said, if anyone feels that a stock KCS joist is the most economical even when built by Johnny GC, I would consider that a valid entry to so long as some justification for it is provided.

Second clarification, instead of amazon cards would shipped cowboy hats be out of the question? Mine is a tad worn since I was last at the stampede and could use an update!

Hell yes. I'll buy anyone a gift card from any online retailer that doesn't make me feel as though I'm taking imprudent risks with my credit card info.

 

[KootK]

I propose a warren truss using WT top and bottom chords with double angle web members.

Thanks for you contribution. My critique (yes, we're doing that):

1) For the better part of a decade, I worked out at the Princeton Club in Madison WI. Overhead, there was a truss of exactly the kind that you describe. Chords and webs maybe a size larger. As you can see, it was used as a joist girder. It actually carried a roof level soccer field as well. I thought the trusses were pretty clever and now want to kick myself for not having some decent photos of them. I don't know what to say... it was the flip phone era. If you wanted a decent picture of some roof structure, you had to haul in your Cannon EOS Rebel ala Andre Agassi and answer a bunch of awkward questions.

2) Do you intend your truss for larger load applications? It seems to me that some aspects of the design would hamper it's economy for, say, the KCS range:

a) Double webs.

b) Cost of cutting WF into WT if they cannot be procured that way.

c) I feel that having vertical webs would facilitate easy, on-site jigging. In contrast, I feel that the absence of vertical webs impairs jigging a bit.

By all means, go ahead and critique my truss... if you can!

...and the angles can be square cut..

I do like that. Clever. I think that this setup, like mine, is pretty easy to paint when required. Yours is a little easier to paint, I think, by virtue of the outboard webs.

 

[KootK]

My approach will the unistrut of OWSJ.

I see it. How would you handle joists length that would not be standard multiples of your hole spacings? Is that part custom? Slotted holes? See below for one option for making the joists field customizable in terms of length. Material savings isn't what you're going for anyhow so maybe something like this would have legs. Kind of like Tri-Force wood joists.

 

[ALK2415]

Dear Kootk
push the bar high like 1000$ [Or make it as books prize / even with some of yours signed in !!!]
then extend the time limit
Iam sure we all love some challenge to perform

 

[canwesteng]

Yeah, I'm thinking just a bit of the top chord needs to cantilever to be truly customizable. The amount of cantilever would be at most one hole spacing, and you set the chord hole spacings close enough that the amount of cantilever of the top chord is tolerable. I imagine the hole spacing is a nice round number, say 4", and suits most applications out of the box.

 

[JoshPlumSE]

I love this discussion!

 

[KootK]

a) Double webs.

I somewhat rescind that. With the WT setup, I'd actually be fine with single webs hopping back and forth across the WT web. What's a little torsion between friends / panel points...

 

[KootK]

push the bar high like 1000$ [Or make it as books prize / even with some of yours signed in !!!]

Thanks for the suggestions. I'm afraid that neither will be feasible for me at this time however.

1) If I send $1000 of KootFam resources to some internet random, there's a pretty good chance that I'll find myself staring down the barrel of a divorce. Frankly, the $150 is inviting trouble. That said, if some other, generous members would like to add to the pot, I would certainly welcome that.

2) Once a tome passes the event horizon of the KootK Structural Engineering Library (KSEL), it never leaves. Not ever. At this point, the KSEL has attained a cultural significance on par with the Library of Alexandria. It's integrity must be maintained at all costs. I'm still seeking a young curator to take the library over once I go off to the big preconstruction meeting in the sky.

 

[Lomarandil]

Fair enough Koot, but if you end up with duplicate physical copies of anything in the meantime... you know who to talk to!

----
just call me Lo.

 

[ALK2415]

@ Kootk
your words is very meaningful to all of us

I'm still seeking a young curator to take the library over once I go off to the big preconstruction meeting in the sky.

I'm sure your directions/inputs here {and other senior members here} are quit educationally impressive [just add Wacom pen to illustrations]
Also thinking of collecting your feedback in small/large engineering book [Troubles Resolving Key-Textbook]

 

[Brad805]

I like the WT solution by kipfoot. While it is likely heavier, that option reduces the number of parts. Single HSS or pipe webs with pre-cut slots would reduce the part count a little more. Presumably, the winning solution is aimed more at being practical and not the lightest. To fabricate anything on site without all the fancy equipment used in the plants would be a feat. Old school joists used a lot of pre-bent rods to speed things up. Those could be produced in various geometries in lengths of say 6'-0" or so for easy handling on site. For shorter spans that might be an option too. QC and engineering for this would be great fun.