Beam Test...watch beam failure in slow-motion!
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- Опубликовано: 3 июл 2014
- Each year, the Precast/Prestressed Concrete Institute (PCI) challenges students to design, fabricate and test a prestressed concrete beam. Each beam is judged on a number of criteria including cost, efficiency, practicality and accuracy of predicted behaviour. Teams from all around the world compete in this international competition. The 2014 team from the University of Toronto includes Rami Mansour, Amos Chen, Karl Shao and Xi Li. The rectangular, variable depth beam is post-tensioned with harped strands.
For the test, the beam was supported at it's two ends with two incrementally increasing loads at midspan. It is interesting to note that the majority of the beams deflection occurs after then steel tendons have yield. In addition, the explosive failure is a result of the concrete crushing at the top of the beam.
Everyone in the comments apparently works for osha..
I'm amazed at the lack of safety glasses and people being so close.
I kept waiting for it to break, and send a splinter through Blue Hat's forehead.
Fuck it
don't you get it? these dudes live on the edge...
I got to work in one of testing labs at NIST (fixing the elevator). They were testing highway support pillars for earthquake designs. They also were testing a keel design for supertankers. Watching a 30' x 8' round concrete pilar twisted and shaken till it failed was very interesting. The keel test was not as dramatic. Made me appreciate all the talent that engineers and architects bring to our everyday lives.
I'm impressed that the beam failed in a controlled manner and never actually completely fell down. If this had been in an actual bridge, the cracks and deflection would likely have been noted and the bridge closed long before there would have been loss of life. Even at the end with massive deflection, the bridge would still not have fallen.
Maybe, but you have to remember that the load press is designed to stop applying load once a certain yield is reached. so at final failure, the load was removed. In a real application the load would have continued to be applied, until free fall of the bridge.
It's a controlled pressure. When the samples break, the hydraulic machine stops.
It was purposely designed as an under-reinforced or balanced design beam. Which means the steel tension reinforcement yields first (and slowly), before the concrete in compression. If it had been over-reinforced, the concrete would have yielded explosively before the steel reinforcement and should be avoided for obviously reasons.
Ladies and gentlemen, a round of applause for the hydraulic press operator!
I initially thought it was a steel beam until it shattered
same here haha
I like this procedure. When I studied some decades ago, we students were given the task to estimate the load when first cracks appear, the deflection at this load and the maximum load the beam would bear. We were given all the information of the continuous rectangular cross section, reinforcement and cube strength and E-module of the concrete. We also had 2 point loads. 4 weeks after casting we could watch the experiment like the one shown. It was very illustrative as we found out, that the formulae worked very good.
popogast who won the pot?
Quite literally the slowest - yet most entertaining video I've seen this year.
66 KN is 14,877 pounds
156 KN is 36,070 pounds
163 KN is 36,644 pounds
if anyone was wondering.
Yeah, that's helpful for anyone still using neanderthal units.
@@Kalumbatsch like me
Wait, did you put an extra 3 in there by mistake in the last one or am I stoned? Not mathing well right now 🤣
Also I i think it is 18.3 tons if anyone is interested and doesn't want to type on a search bar 🤣
Again I may be wrong and just being dumb as shit 😂
I was wondering 💭
Wow, as strong as 163 Fig Newtons! Man, that's a lot!
Hey I worked for coreslab Structers for almost 7 years! It was amazing the stuff we got to erect that came from the yards that were made of concrete.
That was neat seeing the way it flew apart at the top when it finally reached compression failure... Thanks for sharing.
The bridge that collapsed in florida had stress cracks on its underside and it was reported by an employee 2 days before the fall.
Two days is not long enough for a bureaucracy to get moving.
I am sorry, it probably cost lives.
aha, no safety screens
I'd love this job, especially seeing all the different types of failures. I've seen ones on glass before and that was a smashing vid.
It's good to see critical, load bearing construction materials being subjected to such testing.
Lives depend on the quality of these beams.
engineer: i think i can improve this beam a bit..
beam: haha... that cracks me up..
First crack @ 2:00
Close up of 5 large cracks @ 3:35
Major deflection and ultimate failure @ 4:57
Major deflection and ultimate failure up close @ 5:50
Best @ 6:13
Maxwell Goodacre o
Yes... we saw.
Ty
Thanks
Maxwell Goodacre
Which is the best crack?
Spent two years of my engineering internship at the Portland Cement Association Structural Research Lab, the reinforced concrete equivalent of the PCI. While we designed, constructed and tested all manner of bridges and buildings I think my favorite was developing a reinforced concrete railroad tie. The tie not only must resist the zillions of cycles of the wheel loads but freeze/thaw and high temp cycles, abrasion from the ballast, side loads absorbed on curves and braking load must be considered. And to think I took them for granted.
Plus, as I recall from my own destructive testing days, heavy hammering with one of dad's best by ten/eleven year old boys (later I may admit to penny testings on the rails).
That's a solid win for them. Great job guys!
I wished I'd've known about the Toronto Big Beam Contest during the COVID shutdown. I'd've sat for days watching the beam tourneys, 2014 through current, on the big screen in my living room.
lol
@@refuztosay9454 ?
neeeeeeeeeerrrrrd
Pressure from the mother in law.slow at first and then the cracks in the paint start to show.never ending pressure until collapse.
Well it isn’t painted so your incorrect.
Did this beam 'win' because it was most cost efficient, held the most, lived up to the predictions best, easy formation, some weighted combination? Explosive failure wonder whey there is no shielding?
Tons of force on something that will catastrophically fail, and sitting right next to it. Unbelievable
And without safety shield or safety glasses.
Ahh it's ok they went to university lol
Was thinking the same thing, the clap at the end is then all being like “yay we didn’t die on this one, next one boys”
That was a lot more deflection before failure than I was expecting for concrete. The steel must be really stretchy, relatively speaking.
This is pre-stressed concrete, not reinforced concrete. The beam has internal cables which have a designed load applied to them prior to casting the concrete. These cables have placed the surrounding concrete in a "super-compressive" state and are absorbing the tensile load at the bottom of the beam. A standard reinforced beam would have failed sooner and more dramatically.
I have so many questions. What's in the beam? Steel rebar? Tensioned cables? CFRP? What's the concrete made from? Does it have additives? What's the criteria for the test? Looks super fun.
Not sure, a square hollow though is extremely strong as to the way it transfer forces around and I only know that from randomly watching a RUclips vid yesterday that was explaining some inherent failure in I beams. Might be worth searching with those search terms. I wonder if it had tensioned steel cables within.
Thought that paint would never dry!
😑yep
My first concrete beam design project in college asked us to come up with an optimal profile, cross-section and steel reinforcement for a simply supported beam of specified span, to carry a specified load. I came up with a profile quite similar to the one being tested here ie. with a deeper cross-section at mid-span than at the ends. I was surprised however that most beams in practice (like those across highways) have the opposite profile, with deeper ends than at mid-span. Apparently, engineers in practice are more concerned with resisting shear forces at the ends than bending moments at mid-span.
So they just sit around the beam with no safety equipment, no eye protection.:. But hats off to the whoever welded those damn carts!!
Episodic spalling shrapnel events are fairly uncommon beyond teacup saucer range, I expect.
We all love to watch stuff break.. It's important.
This is what engineers do when we are bored. Frack it'..................Lets go break something in the test lab!
It teaches us the limits of materials.
That's why nobody who has some experience with engineering and construction can, in the right mind, believe the official story of 911 and the collapse of the WTC buildings.
LEFM is a magical thing. When this video started I already knew where the cracks would form
what is the Test Method Standard did you use for this test? third-point loading?
Yes, that looks like a safe environment to be in with 163kN loads until failure.
Same thoughts i am having ..sheesh
I guess they know that steel bends and concrete gets smashed with no flying objects...
So even after it cracked and failed at 66kn, it still supported over 150kn and even with many cracks it stilled held strong. Until at least 163kn
Its normal thing for reinforced concrete. There is no fail at 66kN.
Concrete cracks because it can't handle tension, but rebars can handle tension.
@@SAIGUK More accurately, because it lacks the elasticity of the steel rebar.
@@nairdacharles9492 Can't agree.
Concrete has elastic modulus for tension and compression. Elastic modulus is nonlinear.
But concrete cracks only because of lower ultimate tensile strength.
this is my alma mater although electrical eng. but you would have lectures in this building and from an upper floor there were large windows where you could look into the main lab. they were always testing something either concrete or large wire ropes as thick as your arm to failure. this was back in the early 80's so yah i'm old. i'm sure things have changed there in 40 years. at that time the contest i remember was a model bridge with a span something like 3 feet. and materials were mostly anything . the winner was the one with highest strength to weight ration. so most of the models were wood/ composite.
Really interesting video, thanks!
5:50 beautiful how concrete cracking can close without leaving a trace
Almost certainly steel reinforcement springing back and pulling it back into place. Wood also does this, by the way - when it loses moisture horrible looking cracks start to appear, then when the moisture content goes back up it seals back up perfectly like they were never there.
High tech ,fully equipped, state of the art , crack analysis right there.
I like the smattering of applause at the end......jolly well done beam!
Reminds me of CE 380 at the UA (University of Arizona) and Dr. Malvich and Dr. Ehsani back in the day (the 1980’s). Those were the days!
This shows why u have to under reinforce your beam ... So that the rebar yields first and there is ductile failure
Questions guys,
1. for a prestressed beam, does it really need to have a bulge or deep cross section at the middle in order to have a higher bending moment capacity or load rating? Beam of this shape seems to have no beauty mah.
2. So when the strands broke, the beam went kaboom ?
3. In a real bridge, when a small crack is observed at the bottom of the beam, does it mean that the bridge should be condemned?
4. Vidcam you used in the test, how close to the test subject and what danger of being hit by the concrete pieces on explosive failure ?
***** In any beam of any material, having a deep midsection like the one in this video will determine the overall strength and longevity of the beam. It seems like you might understand the concept of what I'm talking about, but think about a ruler standing on its side. You can bend it, but not much. Now add a second ruler standing the same way to increase the depth. It's nearly impossible to break when you try to bend. In terms of a crack in a beam/column on an actual bridge, only severe cracks will determine whether the bridge will need to be condemned. Small cracks could mean anything. As long as the bridge is under similar loading at all times, the crack should remain the same. If the bridge is in severe weather conditions, any crack is a problem. Cracks can be fixed fairly easily. Like any structure, maintenance needs to be done. As long as the student is standing a good 10 feet away, there won't be a problem. If your beam is exploding, then your construction is definitely questioned. I think a bolt failure on a steel beam could definitely cause damage to someone no matter how far away they stand.
+Ozzie Wozzie Original -- you were reading my mind with these questions
The deeper the belly on the concrete beam the stronger it will be since the neutral point will be able to shift deeper into the beam. concrete being ~ 12 times stronger in compression than tension. Not sure if that helps with your question.
This reminds me of how a steel rod is put into guitar necks, at a curve. Then it tightened to straighten out the neck, which would otherwise bend due to the tension of the guitar strings. When the curved rod is tightened, it wants to straighten, and this gives the "underside, if you will" a "lift". The greater the curve, the greater the lift.
Ozzie Wozzie Original im not a smart man by any means but im assuming the purpose for tests like this is to put a structure under a much larger load then it would ever see under practical use, much in the same way osha tests safety equipment? Am i wrong?
My question to you is do you think the beam would perform better if you filled it with self expanding foam or something to that nature?
Cool, during the fast forward bit you can see the burn-in protection on the TV slowly shifting the display.
hi im having my dissertation on flexural response of concrete beams reinforced with stainless steel bars at elevated temperatures...i need help!!
the suspense is killing me
literally no one is wearing safety glasses lol
I noticed that too. These boys are playing in the sandbox but they've not experienced the jobsite.
Nice job guys !
So, next time maybe a bit more concrete shifted to top center? Is there a link to what the limitations are. What about specifics on concrete for this bram? Fiber? psi designed and tested? Mix ratios? Just curious
Ship it before it gets too noticeable.
You mean paint it and ship it lol.
Safety thinking = alien concept
Nice test .
Now this is testing that I could get behind!!
Welcome to the hydraulic press channel, and here we go,
holy shiit!
Quick, Bob, put some spackle on that before the inspector shows up...
how can adjust the setting of flexural test on UTM ibertest machine.kindly send me the information.
2:20 the guys head in the chair moves funny. Too much excitement for me there!
I’m no engineer but is it a good idea to be sitting next to the beam being tested?
And one is walking around..
*no safety glasses
Eh no these lads are what you call invincible gobshites
Yes , if you know what you doing.
@@bahn5ee but you dont know what you're not doing.
That's why It is ideal that the design of beam is tension controlled
Destructive testing is just the best!
It's interesting the way the cracks are fairly evenly spaced across the beam. On in the middle, then one about eight inches on either side and then another about eight inches on either side of those. Is this a sign that the strength of the beam is very uniform across?
is the monitor randomly moving the image to prevent burn-in?
yes exactly
Why no personal protection equipment?
They had helmet.
what's up with the computer screen image floating around when the video speeds up? some built in image burn prevention?
did that beam buckle at failure or was it the prestressed / destabilising load that cause that horizontal movement
You forgot to draw your free body diagram.
Don't forget your shear and bending moment diagrams.
Smart ass
Don't forget the sexy elastic curve.
I think we all know this is missing a crucial axial force diagram
Excellent insight delivered on how to do tests for construction in general - I'm hoping to help build cities on Mars, this sort of thing done with sintered Martian concrete will have to become routine for it to have a chance of really happening.
Thanks for the upload and best wishes for the future from the UK! :)
Given the current focus on redirecting of resources for social progress, initial colonization will likely take another several generations. Much longer if the effort is via a centralized global one, such as a UN Space Agency.
It could happen within the next couple decades if accomplished by private efforts and funding.
Mars is for the taking to the first private group that colonizes regions.
Anyone who thinks living on Mars will be like living on our blue planet is smoking wacky weed. Never going to happen.
@@tigerseye73 Wait, what do you mean exactly? The laws of physics are the same on Mars as everywhere else, concrete is still good for what concrete is good for, steel is still good for what steel is good for etc.
@@CoconutSundae The effort required to do what you dream of is almost insurmountable. Establishing cities on an almost airless oxygen deprived and dry planet is not going to happen. Why would any population of a sane life form even consider leaving a life giving planet like our earth, to relocate to such a baron and un-cooperative planet like Mars? We need to protect our own planet, our Mother, who provides us with what we need to live. Build your environment friendly cities on this planet. Visit Mars if you wish, then come home to your Mother planet having gained prospective and appreciation for what this earth already provides for us. And protect her from harm.
How are the end supports connected to the press? What sort of structure is in the floor?
The beams are supported on triangular shaped structure which looks like a book end. The support structures must be bolted to the floor, which is made of embedded beams and concrete. Yes the floor is probably 10-12 feet thick of reinforced concrete.
Fantastic!!
so many experts in comments sections.
Naively, I had it in my head that in this type of testing all human structure in the test zone was removed to a far distance per civil engineering standards - foolish me.
At 04:25, when "orange helmet/blue t-shirt man" pushes the cardstock? under the beam while under test to sample fallen material - quite interesting - can they forecast the inevitable destructive collapse that accurately?
It does not fall down or explode when it cracks trough.
the load is released because it's a press and not an object on top ☺️
nice even spacing on the larger fxure cracks
Love this content... subbed... go for it. The world needs more engineers! Our bridges are crumbling.
Yet somehow we manage 25mil for gender studies in Pakistan, 20 mil for the effects of downed trees in forest, and 20 mil for for office furniture, among other things. While, as you pointed out, bridges are crumbling, infrastructure is is hanging on by couple strands, and our vets are sleeping on concrete. How did we get here? (Rhetorical)
Engineers are going to be hard to come by when are children our taught 1+1=3 because reeecist. Take it easy man
What we need is more bridge builders. One engineered can design a bridge and use it a dozen times albeit modified to the conditions. It takes a LOT of workers a LOT longer to build just one.
How did you know when the first crack formed? Can't see squat
I believe there was a rapid change in tension sensor reading.
And the crack formation happens are very high velocities
Is the monitor doing that to prevent burn in? It's wiggling up and down
Well spotted, it might be. My OLED TV has something called pixel shift, what you see here might be that in action.
It is notable that the amount of deflection just before the final failure would be clear and evidence that corrections and other safety strategies would give plenty of notice to implement an orderly plan take. Unless of course it occurred swiftly, like for example when my stepmother was the culprit
This is rivetting!
Where is the slo-mo section of the video?
It's over six minutes of watching it fail and I'd say that's slow enough. 6:12 it is in slow motion and shows the break.
wow no safety shields on utm 🥵
Don't need safety shields for concrete, the moment the material gives.. The pressure is gone.
Tradução , não tem?
What is the capacity of the machine?
Why is the screen of the sitting guy moving a bit, like the dvd idle logo?
i had to go re-watch.. but yeah that is kind nutty..? maybe something to do with refresh and the camera?
Probably a plasma or other technology that suffers froms burn in and has a technology to shift the pixels a bit in order to prevent burn in
When Beam fails, switch to a nice single malt
My brother did something similar to a V tail bonanza using bags of lead shot. Caused Beechcraft to implement a design change.
Good job
So was that a good test or a positive test or a result they were looking for because I feel that is 7 minutes of my life ill never getting back.....
If it makes you feel any better, this was a contest between engineering schools to find the best design for a certain set of parameters. We will never know if it was a success or not because we do not know the results of the other teams.
Thats only like 35000 lbs of pressure, if I'm not mistaken? I thought a beam that thick would be able to handle a much more significant load. What kind of application is this beam designed for?
D. Ryan Shaw i tried to look up what "kn" stood for before i commented and it was way beyond my ability of understanding. But i would think it was far greater than that?
Jeff Williams I believe a kilonewton is around 220 lbs of force or so. My line of work requires equipment that is rated at 23kn's or greater and I'm pretty sure that's right around 5000lb's. So 1 kn would be about 220 lbs
were they testing for unconfined buckling at the top?
The weight of the pressing mechanism is being supported/suspended, and is also moving slowly. If it was just a heavy object under gravity being tested, it would have cracked and gone through much faster.
Say no to crack.
yeah, Im just gonna sit here 5 feet away from this fkn thing, no containment devices, nuthin but a hard hat.....till it implodes, really
So long as you're not inside the beam when it implodes, you're golden.
How green was this concrete. Age/days?
Wouldn't you want a few test beams at 7 day intervals from the date of pour to test the failure curve? Just asking.
they tested it on the 28th day.
CoreSlab is nearby. Please put PSI/SAE values in as well as n/m
I like the way they all have hardhats with fuck all to fall on their heads and yet no screens between them and the beam
gowd sake you basically wear what the main guy in charge wants to supply
Under that much stress it's possible something could fly off. Surely the operators would be safer in an elevated position and further away.
It’s concrete it just crumbles
It was not their first beam. That day.
it crumbles and much safer with the gradual force.
in real life their is alot of vibration on beams dose your test account for this or is it strictly load
We casted & tested r. c. beams in our 3rd year in U of Ottawa back in 1978.
Good thing it was recorded in slow mo..... the video finished just as I woke up. Good timing.
I and my colleagues did this back in 1973 at Eng School in Auckland, NZ
I did this in 8th grade.
@@edwardcornell1263 I did this before my first birthday.
what machine used for this test ?
Wow. Just riveting.