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Harvard Model Bridge Testing! Trusses and Beams 

Paul Kassabian
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Learning by Doing!
When I was teaching Structures II at Harvard's GSD, we decided to do a bridge competition where the students design and build bridges with limited materials to span approx 10ft (3m).
We gave three prizes (all of equal value):
1) Best looking bridge as voted by the whole class (before testing took place).
2) The bridge that could carry the heaviest load.
3) The bridge that could carry the heaviest load per self-weight of bridge itself.
Each team loaded their own bridge until failure. They also had a related report assignment which was in two parts:
1) Before testing: Why this design, how they expected it would fail, and under how much load.
2) After testing: How their bridge actually failed, how and why (if) that was different to what they expected, and what they would do differently to improve it.
Thanks to Andrew Gipe for pushing the concept, to the TAs Andrew Gipe, Alex Karadjian, Dimitris Venizelos, and Wen Wen. Also to the GSD Fab Lab Burton LeGeyt and Rachel Vroman and to Juhun Lee for video editing. Most of all thank you to the students for an awesome set of work!
You can find the full video of the tests without commentary here: vimeo.com/128034912
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 structural design projects and years of teaching structures to students.

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25 фев 2023

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Комментарии : 1,5 тыс.   
@zorbl8463
@zorbl8463 Год назад
This would be super interesting to see students try at the first class and again at the last class to see their progress :)
@BruderSenf
@BruderSenf 7 месяцев назад
that would be very fun and interesting, "pure" gut feeling at the start and then see what happens after you added the knowledge to it. love the idea
@DavidDeblaere
@DavidDeblaere 7 месяцев назад
We had this type of excercise in programming class in college. "write a program that finds all prime numbers between 0 and let's say 100.000 as fast as possible". 3 times a year you made this excercise. Everytime you find something to improve in your code or algorythm.
@damageincorporatedmetal43v73
@damageincorporatedmetal43v73 2 месяца назад
Zach cared about production, that's when Mr. Kasperski left...
@damageincorporatedmetal43v73
@damageincorporatedmetal43v73 2 месяца назад
Maam I have to say, your Dad had it rite. Zach was wrong, now just imagine. A 1/4 of a million Dollars to replace what he' F[EXPLICIT]ed up for you. You'r name, name your family...
@JenMarco
@JenMarco 21 день назад
That’s what I love! Then you know you learned something
@joeqiu88
@joeqiu88 Год назад
Dear Mr. Paul Kassabian, I had the privilege of being part of this class, which to me, has been one of the most rewarding experiences provided by GSD. I express my gratitude for your efforts in creating such an engaging and productive learning process. Thank you.
@edwardjarvis3442
@edwardjarvis3442 Год назад
interesting, what do you do now?
@twintek1099
@twintek1099 Год назад
congrats on being in harvard
@brianbreen2499
@brianbreen2499 Год назад
Lol nerd
@jonathansturgisjs
@jonathansturgisjs Год назад
Must kinda suck to know the most rewarding part of your experience there resulted in a quick free to view youtube video showing that you can do at home for about $100 with extremely simple explanations.
@yauya
@yauya Год назад
@@jonathansturgisjs ???
@TimothyR.Heistand
@TimothyR.Heistand Месяц назад
I don't know what I love more... how excited the students get or how excited the teacher gets. This is how education should be done!!
@isar3707
@isar3707 8 месяцев назад
Paul my father was a bridge engineer and worked his whole life building and maintaining structures. Your passion, enthusiasm and attention to detail reminds me very much of him. Wonderful teaching and great to see some engineering passion. Thank you.
@PaulKassabian
@PaulKassabian 8 месяцев назад
That’s very kind of you to share that…thank you…
@AquarianSoulTimeTraveler
@AquarianSoulTimeTraveler 13 дней назад
​@@PaulKassabianthe one thing I like about spaghetti and glue is that it is even structural strength all the way through and you're not going to have some wood that's stronger than other wood making someone structure appear stronger than it actually is architecturally...
@jimhabsfan
@jimhabsfan Год назад
An educator who makes learning interesting AND fun. Well done, sir.
@PaulKassabian
@PaulKassabian Год назад
Many thanks!
@jimhabsfan
@jimhabsfan Год назад
@@PaulKassabian : You're very welcome. I wish I had teachers like you when I was in school, which was about 100 years ago. 😂
@kaboom-zf2bl
@kaboom-zf2bl Год назад
@@PaulKassabian nice reuse of the Ottawa University materials science lab final exam project ... you missed having them do a full failure analysis on the end result as well ... back when I did this at Ottawa University in 1987 the report was 1000 pages long and the bridge I built carried 573lbs of weight before a miniature knot in the wood gave way ... more was learned from that project by everyone INCLUDING the professor that he kept at it until 92 or 3 ... . Balsa and string at 5lbs total bridge weight ... pre tensioned for 500lbs ..
@dangeary2134
@dangeary2134 Год назад
@@PaulKassabian I wonder if you would entertain having anyone that has watched these, and has not had formal engineering to submit a design for one of your student teams to build? Simply put, the team should choose a bridge out of a “pot,” and make it according to the spec given. I would do this AFTER this competition, and as a bonus point to their score if they choose well.
@AbsurdOod
@AbsurdOod Год назад
​@@PaulKassabian hi, Sir. I would just like you to know how much I admire your giggles when the bridges are about to collapse. Proves that you're emotionally invested in your craft. To my memory, my best tutors has always been those who truthfully enjoy the subject they're teaching. I'm sure many of your students will remember you and your lessons for the rest of their lives. Hope this comment reaches you; thanks for the video!
@markharrisllb
@markharrisllb Год назад
RU-vid amazes me how it shows me things I never knew I was interested in. A phenomenal teacher and I imagine every student is proud to have studied under you.
@MohsinExperiments
@MohsinExperiments Год назад
They use the data of the other users that watch similar videos for recommendations. And this is my most favorite thing on the internet.
@cognoscitivos
@cognoscitivos Год назад
Same shit! Im from chile psicopedagogo ajajaj and look im here
@zzzetsulive
@zzzetsulive 10 месяцев назад
low learning curve tbh yes this is a project that is fun but clearly if you are of the mind of "what will fail" then you can almost make the teachers run out of weight
@ReeveProductions
@ReeveProductions Год назад
It would be amazing to start a class with a two week build like this, then finish it with another two week build to let the students demonstrate what they’ve learned.
@bobrikerik
@bobrikerik 8 месяцев назад
The Poly Bridge 4 graphics look insane. And the replay comes with a custom commentary so you know what to improve.
@bsavage5128
@bsavage5128 Год назад
I remember doing this in high school in my architectural engineering and design class. My little balsa wood bridge held 176lbs before giving out! Great fun and an awesome learning experience!
@JustinBrockel
@JustinBrockel Год назад
One of my very treasured memories in school as well. Loved the bridge design project.
@jacketnipple
@jacketnipple Год назад
I could stand on it xD
@agnidas5816
@agnidas5816 11 месяцев назад
yeah ... highschool kids did better than people at HARVARD...
@thwartificer
@thwartificer 10 месяцев назад
​@@agnidas5816Kids bridge could've had a shorter span
@SoloRenegade
@SoloRenegade Год назад
there is NO substitute for hands-on application and learning. Engineering colleges are failing miserably at this of late. This is a perfect example of how learning should be done. Hands-on application, with a little trial and error. Let them test their ideas, take notes, and try again. Couple this with classroom learning and you have a winning combination. So much wasted opportunity in engineering colleges to really give students a truly great education with little extra effort.
@PaulKassabian
@PaulKassabian Год назад
Thanks! It really made a difference with, as you noted, the coupling with classroom learning...it's like concrete plus reinforcement...better together!
@wolli25
@wolli25 Год назад
A lot of colleges participate in student steel bridge competition and concrete canoe. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-bOlt5slVbBk.html
@ceerstar851
@ceerstar851 Год назад
I love how he's just as excited as I am watching the video, yet he was already for it. That's real passion right there.
@btsmochimi7924
@btsmochimi7924 3 месяца назад
Classes like these are life changing. It changes your perspective about learning mechanics. I wish i had u as a teacher sir😢
@oneperspective8601
@oneperspective8601 Год назад
I am an undergrad Structural student. Your students are so lucky. I wish I could have you as a teacher
@PaulKassabian
@PaulKassabian Год назад
Very kind - thanks!
@firecloud77
@firecloud77 Год назад
The problem with weights on top is that balance becomes a factor. The weight should be in a basket that is hanging from the center point of the bridge deck.
@elebeu
@elebeu Год назад
Yes, it's amazing that the one to carry the most weight was the only one that wasn't subjected to twisting forces. Some of the others may have done much better if a portion of the weight had been suspended below in buckets as it was on bridge 13.
@conceptinterface
@conceptinterface Год назад
The first one would have done even better if the loading had been vertical. Some bridges received loading that was much more vertical than others. Suspended weight would have been a more accurate test of relative load bearing.
@tristanmoller9498
@tristanmoller9498 Год назад
I thought designing with that fact in mind was part of the point.
@Tohellem
@Tohellem Год назад
​@@tristanmoller9498 , such a situation is not possible in reality.
@conorstewart2214
@conorstewart2214 Год назад
@@Tohellem there are plenty of twisting forces that a bridge encounters, from having more weight on one side of the deck to wind pushing on sections above or below the deck.
@GERALD_Featureworx
@GERALD_Featureworx 9 месяцев назад
I participated in one of these exercises back in college (35 years ago). Our span was to be roughly 18”. Material efficiency was the goal, so I made mine very light. The weight being used were bricks. Knowing the size the brick, my design used the first brick as a structural element. We ran out of bricks and the bridge never broke. A fun memory. Nice video. 👍🏻
@tonymai8125
@tonymai8125 8 месяцев назад
@gerald_featureworx @GERALD_Featureworx
@FutureEon
@FutureEon Год назад
🎓✨ Mr. Paul Cassabian, I want to express my sincere appreciation for the incredible learning experience you provided through this class. It was truly a privilege to be a part of it. Your dedication and effort in creating an engaging and productive learning process are commendable. Thank you for enriching our knowledge and inspiring us to reach new heights. Grateful for this opportunity! 🙏🏼🌟📚
@gaveintothedarkness
@gaveintothedarkness Год назад
5:11 up until this moment, I thought your students were having a laugh and submitted a plank of wood.
@amelkinelliott7711
@amelkinelliott7711 Месяц назад
Pun intended?
@gbsbill
@gbsbill Год назад
That was amazing to watch as a spectator, I can only imagine the problem solving and learning plus team building that took place to get to the test of all 13 bridges. Thank you for taking the time to record this and let all of us participate.
@PaulKassabian
@PaulKassabian 9 месяцев назад
You're welcome!
@edgedg
@edgedg 9 месяцев назад
This. Great student project, but tripple the value for recording and uploading, with commentary.
@sabrekai8706
@sabrekai8706 Год назад
Now that reminds me of the college I went to between 1973-1976. It was ALL hands on. 2 years of forestry, we were in the bush just as much as in the class, learning by doing. 1 year of welding and fabricating, skills I've used my entire working life. Keep doing it this way, we need people who THINK instead of parroting the party line they are being indoctrinated with. Those young people are having a blast, putting what they learned into actual use.
@ironteacup2569
@ironteacup2569 Месяц назад
The discussions about it is what makes this the best
@Fubeman
@Fubeman Год назад
Just an outside admirer here. I have to say, professor Kassabian reminds me so much of my physics professor. Someone who truly cares about the subject, his students and their overall engagement with the material and makes it all fun at the same time. Well done! Even though I am a graphic designer, I am always interested in all engineering subjects. And I f I had someone like YOU back in the day, I really think I would have become an engineer just because of the way you teach. Well done sire! Well done.
@francisco_.sousa_
@francisco_.sousa_ 7 месяцев назад
I wouldn't fail this, I got my degree from Poly Bridge
@pengujedi4559
@pengujedi4559 2 месяца назад
Yeah same I think I peaked at like #36 in the world in poly bridge 2. Most of my bridges were not bridges though
@novy1198
@novy1198 Месяц назад
@@pengujedi4559 ye thats the main issue of poly bridge player lol, most bridges arent even bridges
@pengujedi4559
@pengujedi4559 Месяц назад
@novy1198 that's why i was good at it i just yeeted the car. Didn't bother with bridges
@billgrundie8478
@billgrundie8478 Год назад
Paul, you are a fabulous educator! So good to see the enthusiasm and interest of the students. They are clearly getting a very special education.
@sleepmanual3718
@sleepmanual3718 2 месяца назад
bro, why did this come into my recommended after the Baltimore bridge collapse though... 💀💀RU-vid is got a sick sense of humor tho
@HumanSagaVault
@HumanSagaVault 8 месяцев назад
This is the kind of professor that you would want to learn from, Good job Mr K! we enjoy your videos so much, more!!
@PaulKassabian
@PaulKassabian 8 месяцев назад
Thanks! 😃
@breebrat56
@breebrat56 Год назад
Soo cool seeing how past and present bridges get planned, tested, and refined! 😊❤
@anuardelcastillo2627
@anuardelcastillo2627 Год назад
Old school teaching is way way more fun and a richer learning experience than digital world. Great to see it up to date again!
@1NightInParisOfficial
@1NightInParisOfficial 8 месяцев назад
This is not old school, look at all the materials being used for such project
@anuardelcastillo2627
@anuardelcastillo2627 8 месяцев назад
@@1NightInParisOfficial string or cable and wood... Whats new on that?
@dr-hero
@dr-hero Год назад
I want to see him play Poly bridge.
@T25de
@T25de Год назад
4:38 I just caught the huge grin on my face as you’re talking about how the students are interested. This is a great looking class Well done sir!
@robsalvv5853
@robsalvv5853 Год назад
We did something similar in my civil eng class 35yrs ago, with a fixed amount of balsa wood for each team to span a 400mm gap. Fascinating to see the much more elaborate designs in the video.
@antardas4830
@antardas4830 2 месяца назад
Me getting this video in my feed after the Baltimore bridge collapse!
@apple54345
@apple54345 2 месяца назад
RU-vid watchers suddenly clicking a lot more bridge related content than normal and the algorithm recognizes the uptick and recommends videos accordingly.
@sleepmanual3718
@sleepmanual3718 2 месяца назад
Bro, I thought it was just me
@1519Spring
@1519Spring Год назад
I'm interested in a chart of how each bridge did on the three criteria: beauty, weight held, material efficiency.
@gregoryesman9442
@gregoryesman9442 Год назад
Should add number of pieces too. System reliability is a very important component
@acywei
@acywei 9 месяцев назад
These are engineers, not architects, function over form, how it should be. xP
@matthewxavier8067
@matthewxavier8067 9 месяцев назад
@@acyweiThat’s when I was the most annoyed when he was talking about looks, all I care about is functionality. It’s not art, it’s a structure designed to hold heavy loads while being as cheep as possible.
@professionalelectronics3158
@professionalelectronics3158 9 месяцев назад
I would recommend AGAINST putting non-functional judging into something that's strictly an engineering discipline. Do you know why STEM isn't a buzzword anymore? They diluted it to "STEAM" by adding "Arts" to it. Then later on they killed it with "STREAM" by adding "Reading." This is also the difference between Japanese and American automotive engineering. Americans usually start with aesthetics first and the shoehorn the engineering into it, while most Japanese manufacturers over-engineer the mechanics first, and then add the aesthetics later.
@Cuuniyevo
@Cuuniyevo 9 месяцев назад
@@matthewxavier8067 Some bridges have stood for centuries, or even millennia. Over that time, many of those bridges have become tied to the cultural identity of the city or nation they were built in. Obviously, function and safety are more important to their purpose in transportation rather than as an artpiece, but form has value too. Think of how many people will cross it, or see it from a distance during the time it is in use. Do you want them to feel it is a necessary eyesore, or should they feel appreciation, awe, respect, etc.?
@ExtinctionHazard
@ExtinctionHazard Год назад
I’ve never watched anything remotely similar to this but I’m pretty happy it got recommend! Enjoyed watching it and I really love how enthusiastic you are about your craft and students!! You are awesome much respect!!
@caballero_kev
@caballero_kev Год назад
I cant believe that I've watched all of your videos and I barely recognized that additively manufactured part that you have at the background! What a masterpiece!
@aaaduccs6667
@aaaduccs6667 Год назад
This is so cool! Teachers that love what they do makes everything better and fun 💗 I can’t wait to see how far these students go in the future
@cyclotronbxl
@cyclotronbxl Год назад
It’s not a matter of knowledge, but a matter of experiences. But if you look only at knowledge, you will find a lot of better university than Harvard, even in USA. To know who they are, just watch where the big ingeneering compagnies get their new recrutes.
@shawnfromportland
@shawnfromportland 11 месяцев назад
i did a 1/10th scale version of this in highschool once and it was probably the most enjoyable thing i ever did in all my school years
@pueyorivers3281
@pueyorivers3281 11 месяцев назад
About the saying, "learning from mistakes/failures' only applies to things like this. Another great day for learning
@PaulKassabian
@PaulKassabian 11 месяцев назад
You got that right! Thanks!
@terrymcchesney383
@terrymcchesney383 7 месяцев назад
Outstanding.....your observation of the intrigue and engagement of everyone in the class, and all cheering for success....as good as it gets
@cristinatroccoliwilliams1389
As a high school educator we have made spaghetti bridges. I have used timber before also. Spaghetti is generally used due to financial and or time constraints. The students are amazed that spaghetti can hold so much weight. It’s a great project, regardless of material, though I would want senior students, like those studying architecture to be using materials closer to those which bridges are made of. It’s interesting to discuss with students shock loading, UDL..etc. great video. Would be interesting to know what constraints you gave the students.
@JonPrevost
@JonPrevost Год назад
Harvard doesn't think much about the financial constraints. I'm in agreement that spaghetti is a good tool for younger folk. I remember a summer camp activity at the local community college that used glue and index cards to make a bridge. Lots of corrugation :)
@MegaLokopo
@MegaLokopo Год назад
One sheet of paper and one foot of tape is an interesting constraint for most projects.
@dazhuoxie9157
@dazhuoxie9157 Год назад
Why not use popsicle sticks? A wonky bridge I made couple years ago held 400lbs+ while weighing 350g or so, it was one of the most memorable and impressive things we did at school
@TheVindicitive
@TheVindicitive Год назад
Sounds like a pointless thing to teach 🙄
@allangibson8494
@allangibson8494 27 дней назад
Spaghetti is a very good analog of concrete. They have almost exactly the same bulk modulus. It would be more accurate however if fine steel wire reinforcing was added…
@rlmpproductions
@rlmpproductions Год назад
This is absolutely amazing! I never even knew this was possible.
@PaulKassabian
@PaulKassabian Год назад
Glad you liked it!
@johnsaborido
@johnsaborido Год назад
I'm from Seville but have lived in the UK for more than a decade. I thought it looked like el puente del Alamillo, but I never imagined you were going to mention it. It made my day. 😊 Who would want to learn with a professor like you!? ❤
@Just1kOoL
@Just1kOoL 11 месяцев назад
This is absolutely amazing! This is what we need in college and high school to make things interesting for everyone. Awesome and congrats to being so awesome!
@watchguy7986
@watchguy7986 Год назад
I love this! In highschool my absolute favorite class was drafting, all T squares and velum. We did a bridge every year and if you got to around 850 e factor you were doing pretty good. They were small and the best ones were relatively simple and light. He lets and my partner do a suspension bridge, nothing like this though. We pulled from the bottom and had a share built into the bridge that accepted the tray pulling down and put weights on the tray.
@user-hs9cl3sy1l
@user-hs9cl3sy1l Месяц назад
Until it broke, I thought that second one was just a 2 by 4.
@samlawrence4670
@samlawrence4670 21 день назад
Which would have held the weight with ease.
@iceman7975
@iceman7975 2 месяца назад
Excellent demonstration,stimulates the mind more that studying it of a textbook.
@TexasEngineer
@TexasEngineer 2 месяца назад
I participated in the Alumni competition at the University of Houston model span contest. These were small balsa wood packages that you could only use what was in the package. Walter, very innovative transmission tower designer caused them to have to rewrite the rules. The new rule was: You can only use glue on the joints. Walter had sliced the wood into fine sheets and glued it back together. He created plywood with no weak ends and the dried glue was stronger than wood. Other things he did to walk away with the win: They could not prevent his best of all. He baked the model in the oven on low heat to dry the wood/glue. Everyone found out that kiln dried wood is much stronger than air dried wood. He sanded the shape to eliminate any excess weight. You have to consider shear in your wood design.
@JK-ft4kx
@JK-ft4kx Год назад
We did something like this in Grade 5 with glue and toothpicks. Obviously not at the same span or weights but it was one of the most memorable projects of my school years. Glad to see this video!
@chrismerklin8460
@chrismerklin8460 Год назад
Yes! Toothpicks and wood glue are great for this contest. It has to be a particular brand and type of toothpick for an even playing field. Span a 12” gap and of course the weight should be hanging underneath from a specific sized block of wood that is placed into/onto the bridge. Sand can be used to fill a bucket hanging underneath. I participated in this at my elementary school’s science fair in the 80’s.
@danmorris8714
@danmorris8714 Год назад
I remember doing something similar to this in my Highschool physics class. We had to span a 1-foot distance between two desks using only plastic straws to make the bridge. I remember making a crisscross arched bridge that held up very well, it was a fun time trying to think of a bridge that would work.
@Abcdexf
@Abcdexf 11 месяцев назад
So nice for them to actually be creative and do their own design. When I had this class in university we had to recreate a moving model of a bridge that actually collapsed and recreate the the conditions that led to its collapse. If your bridge didn’t collapse or collapsed the wrong way you failed the class, while the professor was asking questions about the forces involved and theories behind the collapse. Some people got some really weird bridge collapse cases that were very difficult to recreate.
@honestvalley9
@honestvalley9 Год назад
Thank you Sir for bringing the competitors’ hearts very close to many who associate with the discipline and shear fun.
@toddsmith829
@toddsmith829 Год назад
My high school physics teacher had us do a similar project. We each got the same materials and how to build a bridge spanning 12 in. That was very educational and Unforgettable experience and made the study of Science and physics so much more interesting!
@almaguapa-sailboatliveaboa440
I was IT teacher for 6yrs and had students do their own projects with a common goal. It was just amazing to see and feel the enthusiasm by everyone, except one that wasn’t really into IT.
@HermanWillems
@HermanWillems 29 дней назад
Well their job will be: "Hello IT, have you tried turning it off and on again?" :) just kidding.
@thovanhuynh1697
@thovanhuynh1697 4 месяца назад
"I am Vietnamese, and I wish my country offered such education. Thank you very much; I will continue to follow and learn a lot from you! I hope you produce many more videos like this!"
@1NightInParisOfficial
@1NightInParisOfficial 8 месяцев назад
This is how teachers should be. Allowing the students to express their curosity in the field, outside of writing notes.
@tonywolfe9513
@tonywolfe9513 11 месяцев назад
I like how the professor giggled like a child when the last one cracked and failed. What a wonder to maintain one 's curiosity.
@NonEuclideanTacoCannon
@NonEuclideanTacoCannon 11 месяцев назад
We did this in 7th grade science class, except our building material was newspaper. I absolutely dominated. The trick was rolling the newspaper from corner to corner, as tightly as possible. Some of the other designs were smart, but they rolled the paper into floppy hollow tubes instead of tight rigid sticks, and thus didn't stand a chance. I would have loved the opportunity to extend my model bridge building domination to Harvard, and indeed, around the world, but alas I am a poor.
@agnidas5816
@agnidas5816 11 месяцев назад
you are better off without harvard. Teach yourself programming.
@hariman7727
@hariman7727 11 месяцев назад
​@@agnidas5816or any of the trades.
@gruffsbadmojo
@gruffsbadmojo Год назад
This is how you learn hands on try fail try again . Seems as everyone was involved and talking about outcomes. Bravo.
@chris1298100
@chris1298100 Месяц назад
I like how fun this looks and how everyone cheers and smiles when they see how it collapses and how they can learn from it
@fortuner123
@fortuner123 Год назад
I'm surprised at the low standard of design of these bridges considering the level of the students. I've done this in secondary schools with 16 year old and they have come up with some impressive designs. I am particularly surprised at the cable designs that were obviously in compression. What on earth were the students thinking!
@jeffreyyoung4104
@jeffreyyoung4104 Год назад
They copied an existing design that was anchored and weighted differently. Every design in use, has a certain way of working, and if you don't utilize the design as it was intended, it may fail due to the difference.
@CnCW453
@CnCW453 Год назад
Those cables are typically under tension, but they didn’t account for the movement of the anchor points (towers) which in real life often have cables on the other side of the tower holding it up.
@changw_w9413
@changw_w9413 Год назад
I was having so much fun watching this video. I think this is definitely the best way of teaching, letting students do their research on one subject and verify their understanding through hands-on projects. I can see your students were having a lot of fun in this learning process. By the way, I realised many of the bridges actually failed by laterally torsional bucking. I think that's because the second moment of area in the lateral direction is not high enough, these bridges can be improved by designing the cross section in a closed shape (like circles & rectangles). Based on my engineering intuition (which might not be correct), I think the best failure mode should be failed by tension-compression in order to reach the designed bridge's maximum capability.
@jellenp
@jellenp Месяц назад
I’m tardy to the comments but wanted to point out to all the critics here, regardless of what anyone thinks was missing in the design of the experiment, specified requirements or detailed expectations, etc., the primary points to take away are these (at least some of them): absolutely beautiful learning happened, all teams had to contend with the same problem and requirements as well as the same intrinsic difficulties, all teams had considerable latitude in which to design and explore, teams of students shared their intellectual strengths gaining patience and insight in how to do so successfully and finally, everyone will be mulling over the outcome of their experiment for a very long time, entertaining such thoughts as “Wonder how we could have…” and “I bet if I’d…” and “Why didn’t we…”. This was a gorgeous experiment. Well done. ~from a fellow teacher. (P.S. The brain loves to learn when it is highly engaged.)
@The_Bean_Head_Men
@The_Bean_Head_Men Год назад
This is what content on RU-vid should be like, it's so good you can't help but subscribe because the content is incredible. I really enjoyed this, cheers.
@PaulKassabian
@PaulKassabian Год назад
Glad you enjoyed it!
@shockingguy
@shockingguy Год назад
That was really fun to watch, now what would be a lot of fun is to get as many of the students back together at some point like 10 years out of school and into their real world and have a similar competition that would be an excellent follow on video and honestly you should really do that I just think how much fun you guys would have for that weekend Well done, as a contractor, an electrician and someone who used to maintain 20 story building I wish all engineers spent two years in the field doing some work instead of coming out of school with no practical experience, I get that there are trade-offs its risk versus cost or whatever but when guys like me have to fix stuff that people build week sometimes really want to scream at that person who put this piece of equipment in her room and there’s no way to get it out without blowing a hole and getting a crane Well Done 👏👏👏👏
@catherinemarsh5453
@catherinemarsh5453 Год назад
I am not a student or into building but I really enjoyed this video. Stumbled across it by accident.
@Gomez561
@Gomez561 7 месяцев назад
Architecture grad here studying for licensing exams and your videos are so fun and educational. Thank you :)
@chaco_7288
@chaco_7288 Год назад
i love the way you have to do storytelling, you manage to keep it interesting. Amazing video
@rheeagar623
@rheeagar623 Год назад
I would love to see more of it and would also be great to understand the different forces on the different area and how they could be improved… I definitely studied the wrong subject back at the University 😂❤
@rex8255
@rex8255 Год назад
I love contests like this! I mean, they all took the same class, and yet came up with such different ideas (speaks well of their teacher, to. Like they GOT it, didn't just copy something. That first bridge? I've NEVER seen cables under a bridge like that! NOTE: I also noticed that it didn't actually break, just twisted off it's anchors.
@KabelkowyJoe
@KabelkowyJoe Год назад
Maybe becaus it would be difficult to build?
@NANDOFFDataRecovery
@NANDOFFDataRecovery 8 месяцев назад
I remember this exercise in the first year of high school science in the USA. We only had to span a 12 inch gap. But our bridges were only made from supplied matchsticks wood glue and string. Definitely one of my most enjoyed school memories. One team got caught cheating by hiding steel wire into the design. It still failed before mine which was purely the native ingredients :-) Great fun. I enjoyed reliving the memory watching this video. Thanks for sharing Paul.
@theahm9290
@theahm9290 8 месяцев назад
I just love the good vibes and the enthusiasm that I see on your face and the students faces. Unfortunately, since I live in the Middle East I didn’t experience none of that.. I did a major in Highway and Bridge engineering for for years, and haven’t seen a teacher made such an effort nor were the students engaged in the classes..The atmospheres were simply toxic. I really like what you guys have. I wish I had the chance to experience it, this is making me sad but at the same time. I’m really happy for you guys.
@xiaoxiaoreed8012
@xiaoxiaoreed8012 Год назад
This is great, I did the same thing using balsa wood paper and wood glue at university in England thirty years ago..
@vollschwamm7447
@vollschwamm7447 9 месяцев назад
He seems like the kind of teacher to literally be the one you have the best memory of.
@boltonky
@boltonky Год назад
Two things i took away from this its interesting to see how the forces are applied to the bridge and how failures can happen more due to twisting also that the center point is the weakest on lots of the structures. Which leads me to more questions and thoughts...def love this sort of thing :)
@revertedakhi
@revertedakhi 10 месяцев назад
I never thought I would enjoy watching this kind of video
@tasdrouille
@tasdrouille 9 месяцев назад
Great stuff! I always say an idea is only ever as good as your ability to realize it. This video is also a great example of why precision in execution matters.
@CorporateZombi
@CorporateZombi Год назад
I was frightened for their toes! Speaking as someone who managed to drop a weight on their foot and smash a toe! Do you recall which bridges won the popular vote and efficiency prizes?
@PaulKassabian
@PaulKassabian Год назад
Yup...we had lots of checks at start and throughout to look after toes! I think it was Bridge #4 that won "best looking" and Bridge #13 (the last one) won the other two awards which was lovely to see!
@JustinBrockel
@JustinBrockel Год назад
Interesting! Judging from video alone, I would not have guessed that bridge number four would have been the winner for best looking. As it was beautiful, I thought others would have taken this award.
@MegaLokopo
@MegaLokopo Год назад
These events are much more interesting for everyone involved when the teacher competes as well.
@zuki8124
@zuki8124 8 месяцев назад
I can tell you are great teacher, just by look at how your class learn and still have fun ❤
@roblynch99
@roblynch99 Год назад
great practical teaching.. it was really fun watching how different solutions performed. thanks for posting
@gregfleming3475
@gregfleming3475 Год назад
Really fun class. I would have liked to see a standardized way of applying weights -- the bridge that did the best had weights hanging from the bottom, which stabilized the structure. Most of the bridges actually failed because the center of gravity of the bridge was raised high above the base, meaning any small misalignment in weight caused the bridge to flip.
@lluhu
@lluhu 7 месяцев назад
Exactly
@TheLondonForever00
@TheLondonForever00 Год назад
I can definitely say I would have loved to have studied under paul, he's such a fun teacher. What a great class.
@kaboom-zf2bl
@kaboom-zf2bl Год назад
I did this at Ottawa U back in 87 ... the ORIGINAL first class of bridge busting ... got a nice b+ for the final report on the failure ... and had the leftover bridge for 5 years at home too ... (573lbs for a 5 lbs bridge made of Balsa and string)
@TheLondonForever00
@TheLondonForever00 Год назад
@@kaboom-zf2bl Wow, that's some going!
@kaboom-zf2bl
@kaboom-zf2bl Год назад
@@TheLondonForever00 yeah and I wasnt first ... gt beat by 4 others ... the best took the weight of the teacher ... plus another 35 lbs ...
@brab199
@brab199 7 месяцев назад
Dang, I would’ve killed for classes & a teacher like this especially in high school. I had an extremely tough time learning because my brain was somewhere else 90% of the time due to severe adhd which was found out after all my schooling was done. Learning like this would’ve helped me out a lot
@juliob1080
@juliob1080 Год назад
The model bridge testing project is what made me want to get into the engineering field. I would have loved your class.
@wolli25
@wolli25 Год назад
The majority of the load on a bridge is due to self weight, it can be as high as 85% and more of the total load for cable-supported long-span bridges like those mimicked here. Therefore a more realistic loading would be for the majority of the load to be distributed over the full length of the bridge and a smaller concentrated load or better a distributed load applied over a portion of the bridge. With a concentrated load alone the beam still has a lot of work to do in flexure and the cables don't help as much.
@PaulKassabian
@PaulKassabian Год назад
Thanks Gregor and you're absolutely right on bridges of course. I know we titled it "model bridges" but it was essentially a beam contest and, most importantly, one where the students learned about beam/spanning behavior. They also knew all of them would be loaded until collapse and that could be done at our discretion/fun! Thanks again.
@Raph_254
@Raph_254 Год назад
Excellent content as always Mr Paul..wish we had exposure to such practical structures classes here in kenya🇰🇪
@PaulKassabian
@PaulKassabian Год назад
I'm glad the videos are helpful!
@peterrose5373
@peterrose5373 Год назад
What's stopping you?
@nickkane898
@nickkane898 Год назад
I love the little surprised noises you make each time one of them fails.
@404-Err0r
@404-Err0r Год назад
Amazing. I remember doing this as an assignment in my design and technology class in year 12, our teacher scored us on the weight our bridges held before failure against the weight of the bridge itself to determine the best build. It was a super fun assignment and this video really brought back my memories. Thank you for sharing this. 👍
@PaulKassabian
@PaulKassabian Год назад
You're welcome!
@brunospfc8511
@brunospfc8511 9 месяцев назад
Why is Matt Walsh in the attendence ?
@indigenoussober407
@indigenoussober407 Месяц назад
It’s his dorky brother, Michael 😂
@Jthk4855
@Jthk4855 Месяц назад
Yea
@mrfatrata7038
@mrfatrata7038 Месяц назад
What timestamp
@mrfatrata7038
@mrfatrata7038 Месяц назад
Wait no I meant which person
@jakeMontejo3272
@jakeMontejo3272 7 месяцев назад
4am YT recommendations after searching for beef patty reviews?
@emmanuelcarrero4427
@emmanuelcarrero4427 Год назад
Congratulations to all. Amazing jobs. So much fun and creativity. So cool. 🎉🎉
@flipjuicychic02
@flipjuicychic02 Год назад
Wow this made me miss school and activities like these. Thanks for sharing and good job to everyone. 😊
@johnstrawb3521
@johnstrawb3521 Год назад
Great contest ideas and prizes, Paul. ---For these courses it's far better to require a single, detailed model at the finish. I've seen too many Construction Technology / Structures courses overwhelm students to the point where the 'prize' is merely finishing the course and surviving it. They learn almost nothing as a result.
@PaulKassabian
@PaulKassabian Год назад
Good thoughts...and I agree!
@cristianstoica4544
@cristianstoica4544 Год назад
Looks like a lot of fun! In terms of stability testing the last one cheated a lot with the buckets on the sides and with a lower center of gravity. The moment of rotation is favored by the adition of the buckets. I think this is what allowed it to fail structurally and not on stability. Some of the others might have resisted just as well.
@xonx209
@xonx209 Год назад
I was going to say something similar. I'm surprise the teacher didn't notice this or point it out. Not that good a teacher IMO.
@EelcoWind
@EelcoWind Год назад
I was looking for this comment. I wonder how the other would've fared with the side buckets method.
@23lkjdfjsdlfj
@23lkjdfjsdlfj Год назад
All of the students could have thought of the idea and used buckets, but only one group did - so kudos to their creativity. It's weird that a number of comments and responses imagined the worst case, then magically convinced themselves it was true, and then felt the need to publicly state their thoughts.
@EelcoWind
@EelcoWind Год назад
​@@23lkjdfjsdlfj Speaking of weird, it is weird of you to magically convinced yourself that the people you commented on don't realize that and then felt the need to publicly state this. Of course the students thought of this, if not when loading on their bridge, then at least when they saw the other students do this. But if you're testing a scale model of a bridge, you're trying to simulate the actual thing, so not a high center of gravity for the load as occurs when stacked. The professor could've pointed this out as well, or prohibited the last team from loading with a lower COG. Given the amount of discussion this probably has been talked about, so my guess is that the students agreed this was fine and were just curious about the result. Hence these comments and the wonder of how the other bridges would've fared with a lower COG.
@grahamwilliams2632
@grahamwilliams2632 9 месяцев назад
Awesome to watch. Like it when learning blends practical and theory.
@banstorp1425
@banstorp1425 Год назад
I didn't know I needed to see this video, but I am happy I did!
@ferozahmet195
@ferozahmet195 Год назад
They should make an engineer verse architect competition! As a bridge engineer this was great fun to watch.
@nunyabiz1712
@nunyabiz1712 Год назад
The loading is problematic. The dumbell extends past the side of the bridge causing a twisting force wouldn't be present in an actual bridge with actual traffic loads. Given the narrarator's negative comments in the introduction regarding how spaghetti and glue models used in other schools doesn't test real life structures, it's a little silly to then test these wooden models using a load that doesn't mimic real life bridges and traffic loads. P.S. little sticks of wood don't behave like the steel used in bridges either. I assume the purpose is to teach the principles and test the students' knowledge in a fun way rather than simulate actual bridges and loads so the negativity regarding other schools' approaches is a little disingenuous.
@Paul_Harper
@Paul_Harper Год назад
A load extending beyond the edge of a bridge does not exert any twisting force at all provided it is overlapping the same both sides. Its centre of gravity is… central. Also, actual traffic *does* exert a twisting force unless it is exactly equal on both sides of the bridge - an unlikely occurrence. Bridge design needs to allow for some twisting.
@robertobattiston1
@robertobattiston1 Год назад
Also, wind.
@garyzimmerman8679
@garyzimmerman8679 Год назад
I agree, but the contestant from what I could tell is also the one placing the weight on their bridge. Also the contestants knew in advance what was going to be used as a weighting system to test the weight of the bridge, and could have built their bridge appropriately for the test weights to be used.
@ianbelletti6241
@ianbelletti6241 Год назад
But the twisting forces do exist. If you put a heavy load toward one side of the bridge you will get a twisting load anyway. All bridges have to be designed with twisting forces in mind.
@EatMyYeeties
@EatMyYeeties Год назад
The way the dumbbell is placed adds zero moment to the equation like you mention. It's got equal weight off both sides, so the moment cancels out leading to no bending of the truss. You always calculate moment on the center of mass of the object, and the cent of mass of the dumbbell is square in the middle of the bridge.
@profiskipinternational4402
@profiskipinternational4402 Год назад
4 decades ago i was student in engineering. Beautiful to see the young generation in times of 3D virtuality, coding, CAD, fluid dynamics and A.I. doing some handcraftsmanship in construction. The physical experience engraves much derper in the learning process than just sitting front computer screens where smart 3rd party software is going the anslysis of steess loads. Tks for sharing
@clivewilliams3661
@clivewilliams3661 9 месяцев назад
When I was at the School of Architecture in Leicester, UK in 1970's we had this exact same class challenge albeit without the aesthetic element. The bridges were built of drinking straws, cardboard and balsa wood with some achieving remarkable load carrying capabilities, but then to the students although not the structural engineering tutor, it was not surprising as most of the structures had rigid wire reinforcement buried and hidden within the members! It was only when one of the bridges failed under an impossible load that the reinforcement was revealed. We all learnt many lessons beyond the initial 'build a structure over a span' that taxed our ingenuity and as student Architects how we could improve the structural capability without overt and noticeable structural effort - priceless.
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