Geodesic Dome w/ crows nest

[aaronsewell]

I'm building a dome for the next burn and wanted it to have a crows nest perched on top so we can watch activities from above. Has anyone else done this before and willing to toss me some blue prints to steal ideas from or advice. I've got a few questions:

I know the more vertices there are the strong it will be; but i planned to build a V2 style dome do to ease and less parts, will that be able to support a crows nest? (I've seen it done before)
Does anyone have a math equation or something to figure out the supporting strength of a dome?
How did you get it up there? Build it and then pulley it up or build it on top?

I have found one resource but i have found everything is trial and error when it comes to life and would like to hear your opinions.
http://www.timefold.com/domedeck/

I would hate to spend all the time, effort, and money and building a dome and then throw a crows nest on top and see it crush it.

[666isMONEY]

IMG_7100 (480x640).jpg

This did not look like very many people could be standing on it at one time.
They had a cable (can't really see it, not the two guy wires) that they used as a sky-line or whatever they call those cable/pulley rides.

[melodiousdirge]

IMG_7100 (480x640).jpg

Mother of Dog

[some seeing eye]

Thanks Money for that! A dome of any size needs tools to assemble and disassemble. One of the best is scaffolding. That is a better observation platform. Any platform could be a liability magnet and a lightning magnet. I have seen upper dome pentagons go from tits-out to tits-in from the weight of rain on the cover. What you are describing is a straightforward structural engineering problem and should be engineered.

[Nipple]

IMG_7100 (480x640).jpg

This did not look like very many people could be standing on it at one time.
They had a cable (can't really see it, not the two guy wires) that they used as a sky-line or whatever they call those cable/pulley rides.

Did you take this photo? From the angle, it feels like you were standing on my bed when you took it.

WERE YOU IN MY HOUSE?

ARE YOU IN MY HOUSE RIGHT NOW?

WHAT'S HAPPENING? IS THIS REAL?

(Other possibility, were you my neighbor?)

[torrey.smith]

That's my Dome/Tower/crow's nest/Zip-Line!

We are Sextant Camp, we were located at 3:15 & Esplanade this year.

facebook.com/sextantcamp

The Dome is a 3V 5/9 Kruschke with a diameter of about 27 ft (the D strut is exactly 5.859 ft long). I recommend http://www.domerama.com

I use 1.125" OD structural steel tubes with a 0.0625" wall for the dome.

The Dome is about 16 ft high, with the tower apex and Zip-Line takeoff 48 ft up. The railing of the Crow's Nest is at 52 ft.

Capacity of the Crow's Nest is 5 people.

Vünderbar is the bar we placed above the dome in the tower base. Capacity was whoever could fit. We had as many as 25 up there

Feel free to contact me with any questions

Pics:
http://i.imgur.com/5jpmsbU.jpg
http://i.imgur.com/hqiWvND.jpg
http://i.imgur.com/UILakal.jpg
http://i.imgur.com/m2CAew3.jpg
http://i.imgur.com/y5YRjGS.jpg
http://i.imgur.com/cHqIXge.jpg
http://i.imgur.com/gQRCH4q.jpg
http://i.imgur.com/Xh8y5D9.jpg
http://i.imgur.com/xHxHUmG.jpg

[melodiousdirge]

Wow! Thank you for sharing the photos. I love the way you did the main deck. That crows nest looks scary/awesome as fuck!

[666isMONEY]

IMG_7100 (480x640).jpg

This did not look like very many people could be standing on it at one time.
They had a cable (can't really see it, not the two guy wires) that they used as a sky-line or whatever they call those cable/pulley rides.

Did you take this photo? From the angle, it feels like you were standing on my bed when you took it.

WERE YOU IN MY HOUSE?

ARE YOU IN MY HOUSE RIGHT NOW?

WHAT'S HAPPENING? IS THIS REAL?

(Other possibility, were you my neighbor?)

Ha, ha, it was zoom lens from Temple Guardian's camp. (was visiting a friend there.)

[Nipple]

That's my Dome/Tower/crow's nest/Zip-Line!

We are Sextant Camp, we were located at 3:15 & Esplanade this year.

I may have had dinner with you. I was with Northwest Mist. Three of your folks were eating with our "Hector" or "Beijing Phelps". Super brief, but good meeting you (or your camp mates!)

[torrey.smith]

That was me and my wife and our friend O-Dog! We received this very generous offer to eat amazing food and were like "are you kidding?" Thanks!!!

[vaxination]

its important to note our (sextant's) dome is NOT standard conduit. its engineered for this = ]

[aaronsewell]

Don't worry. I'm definitely not going that extreme. I just want a chill spot that I can look over the playa at.

[Jovankat]

Even if you're not going as high if you're doctoring your dome to support weight in anyway please make sure you know what you're doing. Both the design of them dome and the materials used matter and it worries me just a little that you didn't mention the obvious need to consider the material in you origial post but you did mention wanting it to be easy and not have too many parts. This seems like a pretty hefty project for a first burn.

[torrey.smith]

Even if you're not going as high if you're doctoring your dome to support weight in anyway please make sure you know what you're doing. Both the design of them dome and the materials used matter and it worries me just a little that you didn't mention the obvious need to consider the material in you origial post but you did mention wanting it to be easy and not have too many parts. This seems like a pretty hefty project for a first burn.

I agree. There is a strong urge to go the 2V route to reduce parts count, but the buckling/bending situation with those long struts will lead to much bigger steel than most people can deal with, if they properly size it at all.

I personally recommend the 3V 5/9 Kruschke design because it gives you a flat base with excellent interior space.

I'm all for people building stuff! Just try to understand there is nothing trivial about building on the Playa. It's going to be hard no matter which path you choose. Embrace it!

And for the love of Dog use Grade 8 bolts!

[666isMONEY]

The reason I took the pic was i liked the tower. I'd love to have such a tower (dome not needed) in my back yard. Looked on the internet many times for ideas on how to build one and wondered why no one sells such towers. I have a bunch of concrete blocks in the back yard that I thought of building a tower like the one in this picture except I would put exterior stairs (cemented into the holes in the cinderblocks) made of 4x4's on the exterior.

3075532939_54a4bdb802_z.jpg

[melodiousdirge]

And for the love of Dog use Grade 8 bolts!

Gnerally speaking not necessary and possibly detrimental. The high strength of Grade 8 bolts comes at the cost of increased hardness/brittleness and a lower tolerance for being bent, bashed, abused and reused. Grade 5 bolts may be quite a bit stronger than you give them credit for, and in most cases will be stronger than the steel used in the dome.

[torrey.smith]

And for the love of Dog use Grade 8 bolts!

Gnerally speaking not necessary and possibly detrimental. The high strength of Grade 8 bolts comes at the cost of increased hardness/brittleness and a lower tolerance for being bent, bashed, abused and reused. Grade 5 bolts may be quite a bit stronger than you give them credit for, and in most cases will be stronger than the steel used in the dome.

I do appreciate you advocating at least for Grade 5 (with 80% of the strength).

If it's a shade dome only, glue it together for all I care. If lives depend on it, I'm using the best bolts and sizing them to exceed the buckling strength of the tubing substantially. I've seen 2 inch tubing combined with 1/4 inch cheap bolts and seen climbers all over it. Yikes!

Per your "bent, bashed, abused and reused" statement: a properly designed and executed dome will not require bending or bashing to assemble. Mine goes together without any fuss all the way up to and including the final bolt at the top.

[melodiousdirge]

If lives depend on it, I'm using the best bolts and sizing them to exceed the buckling strength of the tubing substantially.

OK well we could get all pedantic about this, but the fact of the matter in general is that Grade 8 bolts cost 2 or 3 times as much for an extra 20% breaking strength. If you're that worried about it, I'd go up a fractional size and you'll get a much larger strength boost. Hardened bolts are also quite vulnerable to stress corrosion cracking in the alkaline dust. Clearly your structure speaks for itself as an impressive work of engineering; it's not my intent to be "that guy", but I wanted to point out that grade 8 bolts are not necessarily the "best".

I've seen 2 inch tubing combined with 1/4 inch cheap bolts and seen climbers all over it. Yikes!

Come on, is that *really* what you saw? I'd like to see photos of that before believing. 1/4" bolts would probably hold up a big dome with climbers, but I'd be surprised to see anyone build one that way. 3/8" fasteners are already small enough to be a pain in the ass to handle.

Per your "bent, bashed, abused and reused" statement: a properly designed and executed dome will not require bending or bashing to assemble. Mine goes together without any fuss all the way up to and including the final bolt at the top.

I wasn't implying that you made a crappy dome that needed be bashed together place... my point was that things that come to burning man get abused, whether properly executed or not.

[torrey.smith]

Hardened bolts are also quite vulnerable to stress corrosion cracking in the alkaline dust.

I use Ultra-Coated 5/8-11 hardware http://www.mcmaster.com/#91286a396/=tqkiy6

I considered Stainless Steel, but there you go again with the strength problem. Ultimately I like knowing the bolts are overkill, and with eye bolts and eye nuts (which I use frequently for guy lines and zip-line connections) having such small strength compared to the basic strength of a fastener in that size, I go a bit mongo.

Come on, is that *really* what you saw? I'd like to see photos of that before believing. 1/4" bolts would probably hold up a big dome with climbers, but I'd be surprised to see anyone build one that way. 3/8" fasteners are already small enough to be a pain in the ass to handle.

I seent it! https://www.youtube.com/watch?v=DKx15yq ... u.be&t=27s

The tubes probably had 5 times the buckling strength that the bolts had in shear. I was Sad Panda when I saw that.

[melodiousdirge]

I'm surprised those bolts are so cheap on McMaster. OK, I withdraw my cost/benefit objection! Usually McMaster is at the high end on price point too.

I'll have to check out that youtube later - thanks for sharing; I still can't fathom why anyone would do that... I use M10 Flange bolts/nuts on my dome and they are about the limit for what can be handled easily wearing work gloves.

[aaronsewell]

Even if you're not going as high if you're doctoring your dome to support weight in anyway please make sure you know what you're doing. Both the design of them dome and the materials used matter and it worries me just a little that you didn't mention the obvious need to consider the material in you origial post but you did mention wanting it to be easy and not have too many parts. This seems like a pretty hefty project for a first burn.

Thats why I started this thread. So I can figure out all the different variables I need to consider. And I'm definitely not gonna build it for the first time on the playa. Its gonna be made and tested plenty before I get there. And I'm the type of person to go all out when I start something, if I do it I'm gonna do it right. If the crows nest ends up not being possible for the first burn so be it but it will happen at some point.

[melodiousdirge]

https://www.youtube.com/watch?v=DKx15yq ... u.be&t=27s

Damn I was thinking that was footage of the dome in question. Now I feel like someone rickrolled me, and I liked it before I knew what happened.

[GreyCoyote]

I dabble mostly in higher-freq domes, and I have never seen a bolt failure. Strut failures, yes. Bolt failures, no. In fact I have never seen the threads on any bolt used in a dome deformed or rolled in the slightest, which is a precursor to failure.

Maybe the low-freq guys have issues, but for the 4 freqs we use Grade 3 without problems. At 20 and 30 feet diameter, 5/16" grade 3 provide a 4x safety factor.

All this stuff can and should be modeled. If the design needs monster, high-grade bolts then use them. But if you have a 3x safety margin compared to the struts, then a high grade bolt doesnt buy you anything. But they are pretty.

[Rice]

The Thunder Dome has dozens of people climbing all over their dome. Wonder what they use?

[LionsNzebras]

The Thunder Dome has dozens of people climbing all over their dome. Wonder what they use?

I believe that http://pacificdomes.com/ build Death Guilds dome. They are using 3/4 inch EMT I believe, and I am unsure on washer or bolt specs.
This was a purchased package, not something that they built themselves.
From what I know it was commissioned in 1999.
But I could be wrong.

A huge number of people including myself are using domerama.com to do the basics.

But materiel\bolts\washers are all a huge part of the design.

It does not make sense to put a G8 bolt with EMT that will fail well before the bolt itself. In some cases the stress caused by the bolts is detrimental to the materials you use for struts to boot.
Its not crazy important but size is also a factor, long struts cause more failures. Dont cheep out on a v2 if you plan on having even 1 person on it. v3s have shorter struts, but yeah there are more of them.

My first design is a v3 5/9 k design, flat base. 1 inch emt. 165 struts. And I am half way through pressing.

Both Torrey and Grey Coyote have been a great help in the overall function of my ideas and they have kept me from doing crazy bad stuff hehe.

[melodiousdirge]

I believe that http://pacificdomes.com/ build Death Guilds dome. They are using 3/4 inch EMT I believe, and I am unsure on washer or bolt specs.
This was a purchased package, not something that they built themselves.
From what I know it was commissioned in 1999.
But I could be wrong.

You are wrong. Please don't post information you're not sure of - in this case you are grossly mistaken. The thunderdome is built of much heavier steel than 3/4" EMT. My little 24' dome is built with 3/4" EMT and the struts will bend if I hang from them mid span (I weigh around 200lbs). If I had to estimate I'd say the steel is at least 1.5" in outer diameter, possibly larger, and may or may not be EMT. I remember thinking it looked like they used galvanized fence posts.

[Dr. Pyro]

The Thunder Dome has dozens of people climbing all over their dome. Wonder what they use?

Sure as hell isn't common sense.

[trilobyte]

Yeah, +100 to what melodiousdirge said. If you're interested to know you may care to look the group up and reach out to them for more information.

[melodiousdirge]

http://www.deathguild.com/

[torrey.smith]

When I was researching for my dome build I came across the Death Guild Thunderdome description. I think it was something like 2" OD or something. BEEFY.