How Domes Work! (Structures 3-2)

Domes are like arches but in 3D! Here I talk about how curvature can provide stiffness and allow for forces to flow in two directions (principal stresses). Similar ideas apply to shell structures so i start with a magical piece of paper and go into more detail about how domes work!
I'm Paul Kassabian. I'm a structural engineer and a Principal at SGH in Boston, MA. I taught graduate students at MIT for nine years and currently teach on/off at Harvard's Graduate School of Design (GSD). These are videos based on my years of teaching structures to students. Enjoy!

[@MartinClock]

I am so glad I found this! I'm teaching arches and domes in the context of the Romans to sixth graders, and I think this will be a helpful visual. Thanks!

[@PaulKassabian]

Glad it was helpful!

[@CMRHM]

a shell is a series of arch. So smart and cute explanation. Thank you, paul! You should consider to teach structure for future architects taking license exams.

[@smile768]

Fantastic explanation. Domes do compressive and hoop forces together. So simple. Who knew?

[@abelquiron2653]

I have seen the Pantheon many times and it has always left me in awe. Your explanation makes it even more impressive. Thank you.

[@PaulKassabian]

You're very welcome!

[@efy5aru]

Would love a book written by you. You simplify things so well

[@PaulKassabian]

Thanks - I started putting together a book many years ago...that became an iPhone/iPad app for a while although it is where I developed the images I use in the videos...so all good things!

[@2btns920]

Thank you sir! Please never stop making videos... You don't know how much impact this has on budding civil engineers!

[@PaulKassabian]

Thanks - more to come!

[@OverlandOne]

Awesome, thank you.

[@chordsandarches782]

Thank you for your insights into arches and domes. I am looking forward, during my retirement, to playing with these structures.

[@arthurazevedobrito4203]

Spent long time looking for a KZbin channel like this one! Thank you 🙏

[@PaulKassabian]

Thrilled to hear...there just isn't this type of discussion/explanation of structure around much...

[@Allie_G625]

Really informational! Keep doing what you do, can't wait to see this channel grow! 🙂

[@PaulKassabian]

Thanks - working on it!

[@martinwairokpam7184]

I literally said "Yes" with you. Amazing work.

[@PaulKassabian]

Hah - thanks!

[@kirokyo]

Thank you! Hope this is of many more to come!

[@PaulKassabian]

Absolutely!

[@egyptianempress5184]

Thank you for explaining it so clearly!

[@PaulKassabian]

You're welcome!

[@jeanettecook1088]

Fascinating! Another great video! Thank you. 😊❤

[@PaulKassabian]

Glad you enjoyed it

[@sebastiangutierreztorres5691]

Keep it up, Paul. Thanks for this content.

[@PaulKassabian]

Thanks, will do!

[@HesronPoet]

Thank you for this informative video Paul!!

[@PaulKassabian]

Glad it was helpful!

[@timlubrano417]

Great video. Thank you Paul!

[@PaulKassabian]

Hey Tim - thanks for that!

[@devikam.s5279]

I really love the way you presented, Thank you sir

[@PaulKassabian]

thanks - that means a lot!

[@fernandoespinola3482]

thank for share this explanation..! I must confess that I was looking for some information about drums and cymbals. As cymbal physics is not a well detailed issue your video really helped me to understand how this beautiful instrument works.

[@PaulKassabian]

Well I'm glad I unintentionally helped!

[@shihanjanith1804]

explanation is so clear

[@tousifakhtar5934]

Very much impressed by your explanation 🙂

[@PaulKassabian]

Thanks a lot 😊

[@vaibhavjain3234]

Love your explanations

[@PaulKassabian]

Glad you like them!

[@hell_pike9150]

Love your channel. I hope one day I'll use information from you to build my own shed or house 😅

[@maxkipchumba7604]

Thanks, and God bless you for this, very informative.

[@Newerasamearea]

Nice work!

[@PaulKassabian]

Thanks Dan!

[@franko8572]

My guy, I don’t know what you do for a living, but your ability to teach what should be complex and boil it to down for even a moron like myself to understand is incredible!

[@PaulKassabian]

You're welcome. Maybe unsurprisingly I'm a structural engineer...I'm a Principal at SGH in Boston. I used to teach at MIT then at Harvard GSD.

[@franko8572]

@@PaulKassabian Oh wow, that’s quite an impressive résumé!

[@edstud1]

Great video!

[@PaulKassabian]

Thanks!

[@tudorioan5104]

Hi, Paul! Great work, I've learned a lot! Arches, columns, beams, frames, cables/chains, domes... What about the best tunnel section ? You know, these days here in the S-W of Europe everyone is digging AA shelters...😆 Is it catenary best suited for the tunnel section shape ? What do you make of it ?

[@blueckaym]

Great video! Could you elaborate on geodesic domes specifically? And particularly to the effects of rearranging the struts in different angles (while preserving the strong triangles structure). I'm considering building a geodesic dome for a home, and I wonder (in principle - of course I'll hire an architect for precise plans) if it's possible and how to push some struts around to open a bit wider space that can accommodate better rectangular doors and windows.

[@PaulKassabian]

Geodesic Domes is on my list...Bucky, Biosphere, Spaceship Earth...

[@davepennington3573]

@@PaulKassabian make sure you look at Monolithic Domes, they have built hundreds of them using several methods, from small to very large. Their latest tension material is basalt fiber, which has many advantages over steel.

[@HaileISela]

since geodesic domes come out of synergetics, the experiential science of the spherical, omnitriangulated structures of spacetime, i would suggest not breaking the pattern integrity with rectangular doors and windows, but rather go along with the omnitriangulation. it will be well worth it, not just structurally but even aesthetically.

[@ajazmahemoodsayyed4122]

Amazing sir

[@PaulKassabian]

thanks for saying so! Much appreciated!

[@davidgruty]

Paul, What's the best shape to resist vacuum? Also the dome? I guess it's the same you are explaining in this video

[@mohandalshareef3607]

Thanks you I have a question how Long Should You Wait to Remove Concrete domes Formwork ?

[@anandjamdade9156]

Nice Sir

[@blueckaym]

A question about the hoop forces - You mentioned that the bottom experience tension forces instead of compression ones. But I wonder isn't that because we're used to imagine and build domes as hemi-spheres, which do not follow the catenary curve most optimal for arches? Even if it's a concrete or stone dome (that hold very well to compression forces, but poorly to tension) the bottom of the dome wouldn't be stable, unless its walls are thick enough to ensure the catenary curve is within the walls.

[@PaulKassabian]

Thanks for your note. The hoop force is providing restraint, especially at the base, in lieu of any external horizontal support...essentially providing an internal "tieing" of the dome. So, to your note, if domes were more based on catenary geometry that would significantly reduce the hoop forces in the main dome but you would still have hoop forces at the base to provide overall equilibrium.

[@mutsdin6073]

I WISH TO BE LIKE U. SOME DAY.

[@jasmeetsingh48]

sir kindly make video on vaults also.

[@mohammedlasmi649]

Thank you too much

[@deepgora4748]

Sir tell, dome is long life than RCC OR RBC

[@IronMan-yg4qw]

compare the forces of round domes to catenary domes. plz.

[@user-hm6hy1oq2z]

رائع

[@kathryncarter6143]

But what is the reason behind the choice? The dome seems so much more complicated than a standard roof line.

[@rangecow]

Domes (cúpulas) are popular in Mexico. It is said they are natural air conditioners. Is this significantly true. These are not domed structures but structures with domes on top. Thanks.

[@scrappychildhood6633]

Twister proof

[@ChannelRandomMy]

2:55 Wow, is this why balls are bouncy? Everyside of a ball is basically the top with a lot of tension on it, anyone know?

[@FleetenHome]

Human houses in the future are all dome-shaped 👍

[@howlme]

I haven't found yet how the onion domes work, where the load excedes the bearing point, 🤔Why they don't collapse???😳😳😳😳😳

[@belaczako1102]

High. Is the catalonian boveda works in the same manner than domes? kzbin.info/www/bejne/m2aTn5Z3hM54oNk I'm talking about this.

[@PaulKassabian]

Good question! In many ways yes in that they are a 3D assembly that carry loads in compression. The wonderful thing is how there are so many variations of material, geometry, and construction that can use the basics of dome behavior!

[@belaczako1102]

@Paul Kassabian and how they can build them? It works as an arch, row by row until all four side connects, and after that as they build row by row at all side, when they finish a row it holds itself in position? Like the ring in the dome? This is how holow piramyd works also? And how bruneleschi dome was built in firenze? How he could make the structure self suporting with the L shaped brick? You agree the best option to cover that was a dome? And what stop this extremely heavy structure at the base to push the wals outward?

[@hauntedcaptainphoenix5363]

I need to find people to help me build amphibious dome homes that can help us survive doomsday.

[@KFLson]

If it’s clean like glass or plastic clean and you shine flashlight at it…you’ll see 2 lights inside the dome