Another interesting thing to note, you CAN have too much rebar in a beam. Since steel is much stronger than concrete, having too much steel in the tension zone will cause the concrete to fail in compression before the reinforced concrete can fail in tension. Since concrete is a brittle material, this turns the failure mode BACK into a brittle failure, rather than a ductile failure. So the goal with designing a reinforced concrete beam is to have enough steel to have the strength required, but not too much to the point where failure becomes brittle again. Strength AND ductility are both very important
Correct. In other words, having too much steel would result to the concrete structure instantly collapsing without prior warning which would result to hundreds or thousands of death in contrast to having the concrete fail first before the steel which will alarm the people in the vicinity to evacuate before the inevitable collapse since the steel would be able to hold the crumbling concrete first before collapsing
@@nickmeale1957 hard for me to say I don’t have much experience actually designing to know off the top of my head lol. I just had some structural design classes. Also rebar comes in a lot of different sizes so you’d wanna specify the total area of steel in a cross section rather than the number of bars
@@nickmeale1957 Four is the minimum for any main structural support like column or beam but for lintel beams and stiffiner columns that support the walls you can have two depending on how high the wall is
In 2016, an earthquake hit Ecuador and was catastrophic to the infrastructure of the coastal side of the country. The reason being was that to save costs, many buildings were built using seawater for the concrete mix. The salt found in the mix weakened the steel reinforcement significantly, so when the stress came, it just gave in. I think this is something worth mentioning. (this theory might be incorrect? I heard it in the news - I am not a professional in the subject).
i work in scaffolding and all the material that is exposed to ocean air rust really really bad that it makes you think they were sitting there for decades being unused
As an Ironworker who installs rebar and post tension cables as well as precast prestressed concrete this was a very informative and interesting video. You did a great job of explaining everything in layman terms for people who don't do this every day. Great video!
30+ years ago at College we had a year long module on "materials". Part of that was making concrete cubes and testing them. One of the lads on the course worked for a concrete company and brought in some extra strong reinforced cubes and the teacher went ape when they didn't shatter in his testing machine.
As a special inspector and field technician, part of my job includes making these concrete samples and breaking them later in our lab. I think you did a great job covering this subject. The only thing that annoyed me was that you dropped the 20lb weight into the bucket. It may have held a bit more if you would have gently placed that weight in the bucket or had kept tossing small objects in there.
@@ozdagap1809 that's a thing it's how the medical field has become so amazing. Anesthesia and sleeping drugs weren't always present. Also if this was already discovered there's no reason to sacrifice your hand lol
I am eternally grateful.. I can intellectually capture any lesson naturally I have learned. I used to crave dense dives, but now I’ve fluently conceived anything anyone could possibly openly discuss… (it feels like). I have reached a point I get frustrated if it’s not a really really soft spirit explaining the lesson to me. Your demeanor is an anxiety relief as I refine my knowledge base to a head banging wall level. Lolol. If the lesson isn’t GRACEFULLY carried… I’m thinking the script writer does not passionately understand.. and move on. Understanding something and therefor teaching it is sufficient.. understanding something from Passionately discovering it is the essential teachers we need. The bees knees.
I’m currently in my last year civil engineering degree in uni and these videos are so refreshing … it’s like a revision for me and these are the really basic concepts to always remember
You guys are invaluable. I always try to help truckers merge, it's the least I can do. So few people respect or understand how vital they are to everything running smoothly.
Cool. Fun fact. Did you know they found rebars in the Egyptian statues and buildings over 2000 y old?! Yup, scratch your head. So the question is: IS our history fake or did they have some advanced tech back than?
Dua-cam.com/video/rw4z-rSwNjY/v-deo.html, it is a video I found online talking about the origins of COVID, and that the video talks about the west is responsible for COVID, I don’t know if it is true but this video was 10 years ago, and it predicted many things that have become true since then. I love America, but I am with humanity if this is true, if you guys can share this it would be amazinesesd
This is amazing, I work security for active construction zones. Most of which are apartment complexes, and sometimes I work one week and see some areas with cracks and do not enter signs, then within a couple the area is all new concrete and looks like it was redone and not just filled in. All my life I thought that cracks were just going to happen no matter what and all that mattered was the wood structure deeper in the concrete.
I'm not a mechanic. I'm not an engineer. I'm not a construction worker. I've never watched a single video about construction or engineering in the past month. This has been recommended in my feed for whatever reason. I love this video and the concept of the channel.
At 4:36 you expressed very simply what I had in mind each time I was thinking about the way rebars actually work. I thought I just didn't understand. But my intuition was right. Now I understand the world a bit better and that cured my depressive feelings for a minute. Thank you.
I have zero interest in construction. zero. but i saw this vid a few weeks ago (youtube algo) and can't get it out of my head. there is something powerful about a great explanation. it really stays with you. great video.
The cheap way is to genlock 3 or so cameras with a phase offset and then use camera output containing the moment wanted. Maybe he had more than one beam? But it isn't that hard at all.
Dominik Schaefer Tension problems really stress me out, although they aren't a lot of work. Despite this, somehow they still use a lot of energy due to very low efficiency in doing them.
Working as an Industrial Climber that helps out building my bosses "concrete bunker" as we like to call it has me really interested in these types of videos often times, I knew pretty much everything but since I am German I find it fascinating learning these things in two languages.
Think of concrete as the opposite of rebar. Concrete is for compression - not tension, because it pulls apart easily. Rebar is weak in compression, and will bend easily, but great for tension, because you can pull on it with enormous force. Combined together... using the best traits of concrete and steel wire or bar - and you have a great combo for structures.
No so. Rebar (and structural steel in general) is very strong in compression too. Don't mistake the fact that (relatively) thin bar of steel bends easily with having low compressive resistance. The reason it bends easily is because it has a low second moment of area, to which deflection is proportional.
@@isoaxe To put it simply, it's slender 😀 I'm an aero engineer so no concrete experience. Under compression, does the rebar buckle? I don't know if that'd be realistic because the concrete should fail before you get high strain/deflection, but if the concrete could deflect I'd imagine it provides some lateral stability to the rebar.
I'm having a new house built and they are doing post tension foundation and now I understand what that means. I appreciate the quick informative video.
People joke about the “3am content” a lot but it’s nice to see how many of us are simply curious about the world around them. In an age of alternate facts and outright science denialism. Curiosity is more important than ever.
what about when the scientist themselves disagree, or use correlation and causation, something we were always told to was wrong before. I’m curious af about that
I'm not sure why this video came into my recommended feed, but I'm glad it did. Very thoroughly, interestingly and succinctly explained! Thank you for the video!
You do a good job at pulling young peoples attention towards civil engineering, I bet at least one person has been influenced to go into that field by you
even if people just appreciate the wonder of modern infrastructure and the time scales it spans, he has done something awesome. Infrastructure is such an unloved child of politics - the decisions span multiple election, if not generation and people take it for granted.
Around 30, haven't decided what I wanted to do yet because so many domains interest me and I have not had pressure to make that kind of choice yet, but I love every video this guy has made to date basically and his rather casual and intimate approach to the subject (the topics of which would actually be quite dire in terms of consequences if there would ever be, uhm, catastrophic failure I guess is the term? ;) Always looking forward to next one!
This might be just another comment on youtube, but I really wanted to say thank you for making these videos. Since I discovered this channel I've been really enjoying watching them. Wish you were my teacher in college, but here you're teaching with ease the basics about some complicated topics to thousands or millions of people through the internet. Thank you.
Have you done an episode on centrifugal force? Specifically relating to centrifugal pumps, you’re incredibly talented at explaining topics and would love to have a video to share with co-workers. Thank you for all you the knowledge and keep doing what you do!!
Hi just wanted to drop a comment saying i watched this video last night to understand more about reinforced concrete for my exam the next day..and guess what..i could answer a question by remembering this video and its content..thank god i stumbled upon your video...keep it going and thank you so much
I work in civil engineering inspection and testing, and it always amazes me finding out what I’m testing (if I haven’t sampled myself personally from site) for what project to get the bigger picture of the scope of work.
Nice video. Also to add: Concrete beams that pass over columns need to have more steel at the top due to tensile stresses occuring over the column. It is also important to note that steel structures alone are not fire resistant (they deform with heat etc) so the concrete cover acts as fire proofing. However, not having sufficient concrete cover over the steel can affect this and can also cause “concrete spalling” if moisture penetrates cracks in the concrete and cause corrosion. Concrete spalling is when the concrete face is pushed off due to expanding steel as a result of excessive corrosion/rusting. There is constant research going on now to find ways to protect the steel with additives mixed into the concrete during casting.
The problem with the world trade center design was the outer wall panels and the floor joists. Once the central columns were compromised, the building lost its strength in the impact area and as the outer wall panels moved outwards the floor joists, that were supported by the wall panels, fell onto the level below. The design was to allow maximum open-plan office space without having columns everywhere. But the terrorists knew exactly where to hit to destroy the main central column.
Very simple and well illustrated explanation in a few minutes. Maybe i should recommend this video to some of my former lecturers (civil engineer here).
I teach a beginning Engineering Principles class. My students have been studying this exact topic for the last week. Tomorrow they are going to make small plaster beams that will span 1 foot. They will be able to add sand, rocks, fiber, glue, cable, wire, fiberglass grid, etc. They even have the choice between plaster of Paris or dental plaster. There will be 2 winners, the best strength to weight ratio and the best strength to cost ratio. I plan to use your videos for next year, keep up the good work. I will post a video of some of the student designs soon. Also, if you are ever in the SLC area, I would love to have you as a guest speaker.
Here is the video of my students breaking beams. ua-cam.com/video/HchcobNa8AI/v-deo.html It is a long video due to lots of beams. You don't have to watch all of it to see how different mixes and reinforcement can change how strong it is and how it breaks. The record was 705 pounds.
Well done. Reminded me of the Hyatt Regency walkway collapse even though concrete was not at fault. As a city inspector/engineer I had to closely watch contractors who often didn't follow design specs, cut corners and lackadaisical engineers who verbally authorized changes without engineering reviews and change orders. Getting my life threatened by a unscrupulous contractor isn't fun.
@@Eugenepanels the trouble is, the person handing out threats is the one who access to large holes that get filled with concrete, if you catch my drift.
I'm almost certain that these videos are aimed at a young audience but every video I see is captivating. Lucky I don't have to do the hard number crunching that really makes things tick.
I've shared these with my daughter who is a Sophomore of Civil Engineering and she finds them very interesting and helpful despite their rather basic subject. It is a nice way of understanding what makes CivE and materials science useful.
What happens over time with rebar rusting and "vanishing" inside the concrete. I know today rebar comes with a plastic shroud to keep moisture out, but the nature of manufacturing causes nicks in the plastic. A fascinating picture I saw was in road construction from the 60' compared to days of road work; the amount of rebar in a raised road support than in now is 90% more. I do enjoy your channel. Thank you for producing them!
Rebar generally doesn’t rust inside of concrete because there isn’t oxygen available for it to oxidize. Actually, the reason rebar usually is embedded about an inch inside a beam rather than it being on the surface, where it would provide the most benefit in terms of reinforcement, is because that 1 inch of concrete is meant to protect the rebar from weathering. Like he mentioned in the video, the concrete has to crack for the rebar to have any effect, so when designing a beam like the one shown, the structural engineer actually ignores any capacity that 1” concrete cover may provide and uses the capacity of only the steel by itself, so it is actually purely to protect from things like weathering and fire.
Steel can rust from the old practice of adding calcium to the concrete to cure the concrete faster. The calcium eats away at the metal causing failure of the concrete.
Hey, I have just started watching your videos. I am a building supervisor and commercial diver and I have really found your videos informative and easy to watch. You have done such a good job of covering important aspects while not overloading with information given the relatively short time you have to explain a topic. Awesome job
Hey in not an engineering major or really care about the subject, but I love the way you explain these topics. It's super engaging and I actually find myself looking forward to learning and seeing what you have to say. Thanks Grady!
There are so many good quotes from his videos my favorite is ""engineers generally try and avoid building civil structures out of liquids." From the quicksand video. I would love either of these on a shirt
"a length of strong cord made by twisting together strands of natural fibers such as hemp or artificial fibers such as polypropylene." You're correct but for the wrong reasons. Way to go.
My dad is a civil engineer, so I'm aware how much more you can talk on concrete! So many different recipes! And add ons for the concert! Also how important it is to use vibrators while casting!
The most interesting thing I learned about concrete when I got into carpentry is that concrete and steel expand and contract at the exact same rate, which is why steel reinforced concrete doesn't immediately crack. I never thought about it before they taught it in my apprenticeship but I found that interesting for some reason
@retsaM innavoiG well it's true buddy. That's why bridges and skyscrapers and shit aren't full of cracks. Roads are because the ground heaves but that's a different cause
Thanks for the video. I've heard that adding polymers to the aggregate can be an effective way to reinforce concrete, and in some applications can even replace rebar.
This stuff is really cool. I wish I learned about this type of thing when I was younger. Getting to see what everything around us is made out of makes the use cases of applied math and science very apparent.
If anyone is wondering pre tensioned slabs are reinforced with tensioned steel cables. Also on reactive soils engineers tend to put 2 layers of mesh/rebar in. Bottom layer for the downforce of vehicles and a top layer to stop the ground heaving the concrete up from below.
Threaded rod is a terrible idea to reference Re-Bar. Re-Bar is made from a mild, low carbon, high ductility steel. This allows much more 'strength' from the metal, it has a longer durability for external and internal forces. Meaning it can actually stretch before breaking. Threaded rod is made from a myriad of materials, with my uses finding them in the higher carbon range. Higher carbon content allows the threads to retain their shape and not stretch as much with normal torque levels usually required of them. Much like bolts, which are mostly higher carbon. Not only that but the sharp ridges formed or cut for the threads provide a very nice shear point allowing threaded rod to break with relatively very little force, Re-Bar, not so much. Your video still shows the relation and still works well enough for most purposes. But you did ask for what we thought, and this is my thought.
Actually threaded rod is quite appropriate for a demonstration. Even the smallest size rebar (#3) is way too big for the size "beam" he was testing. I used a number of rebar models when I did a lot of model slab tests 50 years ago ranging from twisted strands of tie wire to threaded rods.
Grady, thanks so much for all the prep work you do for your videos. I have learned so much! When I was a child, my dad decided to add on to our home. He decided to use cinder block instead of reinforced poured concrete for our basement walls. (Rebar = reinforcing bar) Unfortunately, I spent the rest of my childhood bailing our basement out every time it sprinkled outside. The water sprayed through the cinder block like hundreds of shower heads. When it rained, my older brothers would run around with a pencil and circle all the streams to later go back and smear on this water proofing paste used specifically to waterproof cinder block. If you're wondering, no it didn't work.
are you able to produce the energy from atmospheric pressure by using a large scale android's barometer means big modal of android barometer ,say a kilometres diagonal large area could produce 27kilowatt energy per day
So the next time someone says they have concrete evidence against you, you just give them some stress
and tension!
JoulSA But what if they reinforce it?
@@wasilqayyum If that injures anyone they will put you behind rebars.... sorry...I'll show myself out.
@@macforme nice one lol
Tension to be accurate. Compression is still a stress but concrete handle it very well
Ah yes... That 3am content.
Ha
12:56 am content for me
3:44am on the dot
I was watching other videos on this channel at 3am, it's now 5:52am and I've arrived
Ah yes... That UA-cam rabbit hole content
Another interesting thing to note, you CAN have too much rebar in a beam. Since steel is much stronger than concrete, having too much steel in the tension zone will cause the concrete to fail in compression before the reinforced concrete can fail in tension. Since concrete is a brittle material, this turns the failure mode BACK into a brittle failure, rather than a ductile failure.
So the goal with designing a reinforced concrete beam is to have enough steel to have the strength required, but not too much to the point where failure becomes brittle again. Strength AND ductility are both very important
Correct. In other words, having too much steel would result to the concrete structure instantly collapsing without prior warning which would result to hundreds or thousands of death in contrast to having the concrete fail first before the steel which will alarm the people in the vicinity to evacuate before the inevitable collapse since the steel would be able to hold the crumbling concrete first before collapsing
Would having four steel rods in his structure be overkill?
@@nickmeale1957 hard for me to say I don’t have much experience actually designing to know off the top of my head lol. I just had some structural design classes.
Also rebar comes in a lot of different sizes so you’d wanna specify the total area of steel in a cross section rather than the number of bars
@@Kdot19 Interesting
@@nickmeale1957 Four is the minimum for any main structural support like column or beam but for lintel beams and stiffiner columns that support the walls you can have two depending on how high the wall is
In 2016, an earthquake hit Ecuador and was catastrophic to the infrastructure of the coastal side of the country. The reason being was that to save costs, many buildings were built using seawater for the concrete mix. The salt found in the mix weakened the steel reinforcement significantly, so when the stress came, it just gave in. I think this is something worth mentioning. (this theory might be incorrect? I heard it in the news - I am not a professional in the subject).
Salt, moisture, and oxygen can corrode metal much worse than rust. So you are correct
Chlorides cause corrosion in concrete as well as steel. Bad news.
What an epic failure. To think that they would cheap out on something like that is mind boggling.
i work in scaffolding and all the material that is exposed to ocean air rust really really bad that it makes you think they were sitting there for decades being unused
basalt rebar fixes that
Recommended:
Video games
Video games
Video games
Video games
Why concrete needs reinforcement
Video games
Jaja
You made the right choice.
@@pierreo33 😯
It's because of gamers like me who care about the world. ;)
(I was forced to do this irl, my brain man....)
Don't forget somolian pirate videos
"Stress in this case doesn't mean anxiety or existential dread" damn dude you really know your audience hahahaha
Jorge Uresti *crying*
Hahahahahahahaha
Lmao
that
hit close to home😢
Want to like, but 666 is just too perfect
As an Ironworker who installs rebar and post tension cables as well as precast prestressed concrete this was a very informative and interesting video. You did a great job of explaining everything in layman terms for people who don't do this every day. Great video!
30+ years ago at College we had a year long module on "materials". Part of that was making concrete cubes and testing them. One of the lads on the course worked for a concrete company and brought in some extra strong reinforced cubes and the teacher went ape when they didn't shatter in his testing machine.
Remember, just because you're strong doesn't mean you don't need support from others.
Deep
Harun Suaidi whoa dude u blew my mind
Always lift with a spotter
Harun Suaidi DID YOU JUST
A.K.A the Lebron James effect.
As a special inspector and field technician, part of my job includes making these concrete samples and breaking them later in our lab. I think you did a great job covering this subject. The only thing that annoyed me was that you dropped the 20lb weight into the bucket. It may have held a bit more if you would have gently placed that weight in the bucket or had kept tossing small objects in there.
But would he get his hand out in time?
@@person_perhaps Sometimes sacrifices must be made in the name of science.
@@alexharkler 😂ah. Yes. Sometimes people have to have their bodies dissected while awake in order to further science
@@ozdagap1809 that's a thing it's how the medical field has become so amazing. Anesthesia and sleeping drugs weren't always present.
Also if this was already discovered there's no reason to sacrifice your hand lol
It also should have been a test to rip that concrete in half, not tear a hook out of it.
Ive been in construction for about 3 years now as a laborer and this explains so much. Thanks!
ya da güçlendirmeyip arkasından kader diyebilirsiniz arkadaşlar :)
or you can say "destiny" after not strengthened concrete :)
“You shouldn’t make a rope out of concrete.” Well said.
Crap! going back to the drawing board...
Rope should only be made from rope
Note: *make rope out of rope*
Well there go my weekend plans
Anyone know where I can buy a concrete rope ?
Algorithm out here trying to make people experts on the Miami Condo collapse.
Word
😂I just watched a video about that whole thing
ikr, those engineers knew fuck all about what they were doing, they shoulda watched this video.
Lol I was about to mention the same thing 😅
I came to the channel after the I-40 bridge failure. I guess the country is literally falling apart.
I am eternally grateful..
I can intellectually capture any lesson naturally I have learned. I used to crave dense dives, but now I’ve fluently conceived anything anyone could possibly openly discuss… (it feels like).
I have reached a point I get frustrated if it’s not a really really soft spirit explaining the lesson to me.
Your demeanor is an anxiety relief as I refine my knowledge base to a head banging wall level. Lolol.
If the lesson isn’t GRACEFULLY carried… I’m thinking the script writer does not passionately understand.. and move on.
Understanding something and therefor teaching it is sufficient..
understanding something from Passionately discovering it is the essential teachers we need.
The bees knees.
I’m currently in my last year civil engineering degree in uni and these videos are so refreshing … it’s like a revision for me and these are the really basic concepts to always remember
Man, this reminds me of when I studied civil engineering at uni. I dropped out to eventually become a software developer. Thanks for reminding me why
lmao
Dropping out must feel free and horrifying at the same time. I'm so hesitant.
lol
Why did you stop studying civil engineering?
@@joshuaarnold1895 i think civil engineering is one of the hardest engineering majors
I work in flatbed oversize. Hauling rebar safely, in a timely manner. Is something I take much pride in my work ethic. Great video man.
Wishing you good fortune. An actual essential worker😎🤙
You guys are invaluable. I always try to help truckers merge, it's the least I can do. So few people respect or understand how vital they are to everything running smoothly.
Cool. Fun fact. Did you know they found rebars in the Egyptian statues and buildings over 2000 y old?! Yup, scratch your head. So the question is: IS our history fake or did they have some advanced tech back than?
@@outlawedTV88 where u here tht my guy? Onion News network?
Dua-cam.com/video/rw4z-rSwNjY/v-deo.html, it is a video I found online talking about the origins of COVID, and that the video talks about the west is responsible for COVID, I don’t know if it is true but this video was 10 years ago, and it predicted many things that have become true since then. I love America, but I am with humanity if this is true, if you guys can share this it would be amazinesesd
This is amazing, I work security for active construction zones. Most of which are apartment complexes, and sometimes I work one week and see some areas with cracks and do not enter signs, then within a couple the area is all new concrete and looks like it was redone and not just filled in. All my life I thought that cracks were just going to happen no matter what and all that mattered was the wood structure deeper in the concrete.
its fun to watch, as an Electrical Engineer, this helps me quite a bit on understanding the basic theory on re-bars..
The algorithm has struck again. RIP to those poor people in Miami
What happened?
@@coredetta building Collapsed and some people are missing under the rubble but an engineer called it 3 years prior but no one listened
@@coredetta Damn yo, living under a rock
Damn I was wondering why this was recommended, but that makes sense. RIP
Lol yep algorithm is working lol. This is good information too.
I'm not a mechanic. I'm not an engineer. I'm not a construction worker. I've never watched a single video about construction or engineering in the past month.
This has been recommended in my feed for whatever reason.
I love this video and the concept of the channel.
At 4:36 you expressed very simply what I had in mind each time I was thinking about the way rebars actually work. I thought I just didn't understand. But my intuition was right. Now I understand the world a bit better and that cured my depressive feelings for a minute. Thank you.
I have zero interest in construction. zero. but i saw this vid a few weeks ago (youtube algo) and can't get it out of my head. there is something powerful about a great explanation. it really stays with you. great video.
2:47 You got really lucky to get a frame while the concrete was cracking.
or he has a really good high speed camera?
video is good at that.
"video is good at that."
A conventional camera is very bad at that. Unless you're extremely lucky.
The cheap way is to genlock 3 or so cameras with a phase offset and then use camera output containing the moment wanted. Maybe he had more than one beam? But it isn't that hard at all.
@@CitroenDS23 "Instant" would have been a better word choice than "moment" in this topic, LOL. i.e. bending moment.
Material stress is not unrelated to anxiety - at least when having to do the calculations in college
Dominik Schaefer Tension problems really stress me out, although they aren't a lot of work. Despite this, somehow they still use a lot of energy due to very low efficiency in doing them.
I feel ya
Dominik Schaefer deflection equations, stress transformations are a pain in the ass.
Same :-)
Cold sweats and flashbacks to structural analysis.
4 years later, this comes up in my recommended. i understood everything you said, surprisingly. nice video
Working as an Industrial Climber that helps out building my bosses "concrete bunker" as we like to call it has me really interested in these types of videos often times, I knew pretty much everything but since I am German I find it fascinating learning these things in two languages.
*Just finishes making concrete rope.
“Well fuck, now ya tell me!”
Think of concrete as the opposite of rebar. Concrete is for compression - not tension, because it pulls apart easily.
Rebar is weak in compression, and will bend easily, but great for tension, because you can pull on it with enormous force.
Combined together... using the best traits of concrete and steel wire or bar - and you have a great combo for structures.
The exact same lesson my late father taught me .
No so. Rebar (and structural steel in general) is very strong in compression too. Don't mistake the fact that (relatively) thin bar of steel bends easily with having low compressive resistance. The reason it bends easily is because it has a low second moment of area, to which deflection is proportional.
@@yavuzyurur7129 where did your early father go?
@@isoaxe Theoretically yes, but practically thin rods are prone to losing stability when you compress them.
@@isoaxe To put it simply, it's slender 😀
I'm an aero engineer so no concrete experience. Under compression, does the rebar buckle?
I don't know if that'd be realistic because the concrete should fail before you get high strain/deflection, but if the concrete could deflect I'd imagine it provides some lateral stability to the rebar.
This is one the rare videos where I don't even think of skipping. The narration, the illustrations, etc. are perfect (at least for me).
I'm having a new house built and they are doing post tension foundation and now I understand what that means. I appreciate the quick informative video.
I worked as a CMT and we would stress cables post pour and no one ever explained to me the purpose beyond “the boss said so” thanks for elaborating!
That always drives me crazy. I do a much better job knowing WHY I need to do something instead of just being told "because I said so".
well the boss says so to maximize the strength of what ever your building with that reinforced concrete
@@raven4k998 Thanks, we also watched the video.
@@raven4k998 shh guys he works for the boss! Look busy!!!
And never question the boss man's authority 🤐
Loool
People joke about the “3am content” a lot but it’s nice to see how many of us are simply curious about the world around them. In an age of alternate facts and outright science denialism. Curiosity is more important than ever.
Don’t think anyone is denying consistently provable “concrete breaking easier than with rebar inside it”.
@@superchase4106 you'd be surprised with people
@@ZethoYT yeah 🤣
what about when the scientist themselves disagree, or use correlation and causation, something we were always told to was wrong before. I’m curious af about that
@@superchase4106 The flat earthers haven't advanced to that point yet
I'm not sure why this video came into my recommended feed, but I'm glad it did. Very thoroughly, interestingly and succinctly explained! Thank you for the video!
LOVE this! So cool and informative. I always wondered why they add that metal grid into concrete sidewalks.
You do a good job at pulling young peoples attention towards civil engineering, I bet at least one person has been influenced to go into that field by you
even if people just appreciate the wonder of modern infrastructure and the time scales it spans, he has done something awesome. Infrastructure is such an unloved child of politics - the decisions span multiple election, if not generation and people take it for granted.
Around 30, haven't decided what I wanted to do yet because so many domains interest me and I have not had pressure to make that kind of choice yet, but I love every video this guy has made to date basically and his rather casual and intimate approach to the subject (the topics of which would actually be quite dire in terms of consequences if there would ever be, uhm, catastrophic failure I guess is the term? ;)
Always looking forward to next one!
Connor Hyland he's very informative and opens up alot of doors cool channel
I don't have much interest in civil or structural engineering but I still thoroughly enjoyed this
I'm late, but I do love the thought of it. However, I've already made up my mind into being a mechanical engineer.
This might be just another comment on youtube, but I really wanted to say thank you for making these videos. Since I discovered this channel I've been really enjoying watching them. Wish you were my teacher in college, but here you're teaching with ease the basics about some complicated topics to thousands or millions of people through the internet. Thank you.
Have you done an episode on centrifugal force? Specifically relating to centrifugal pumps, you’re incredibly talented at explaining topics and would love to have a video to share with co-workers.
Thank you for all you the knowledge and keep doing what you do!!
For 20 times in a row I’ve been suggested this. Now I finally watch it.
I've already watched it and it just showed up on my front page again
Hi just wanted to drop a comment saying i watched this video last night to understand more about reinforced concrete for my exam the next day..and guess what..i could answer a question by remembering this video and its content..thank god i stumbled upon your video...keep it going and thank you so much
Great 👍👍
Never thought I would find you here HAHAHA
Same
There is nothing very special in this video tbh that just reinforced concrete 101 first week
Mansour mohamad doesn’t mean that it is not helpful 🤷♂️🤷♂️
I do pool construction, it’s actually pretty crazy how we bend and shape the rebar to reinforce the pool before putting concrete
We use it here for decades in every type of construction ,iceland
Just 10m. Super easy
@@DoseOfJapan 10m? lol, well what we use 3/8 #3 & half inch #4 for pools, half inch for the beam but yes it’s easy if you know what you’re doing lol
I work in civil engineering inspection and testing, and it always amazes me finding out what I’m testing (if I haven’t sampled myself personally from site) for what project to get the bigger picture of the scope of work.
Yeah I guess it's cool till you work with it everyday then it'd just a pain in the ass I build foundations and I hate rebar absolutely hate it
This is a most perfect video. You explained this better than many an engineering professor! Thank you.
this is one of the most interesting and educational videos I have ever watched in here, practical application! I want more!
Nice video. Also to add: Concrete beams that pass over columns need to have more steel at the top due to tensile stresses occuring over the column. It is also important to note that steel structures alone are not fire resistant (they deform with heat etc) so the concrete cover acts as fire proofing. However, not having sufficient concrete cover over the steel can affect this and can also cause “concrete spalling” if moisture penetrates cracks in the concrete and cause corrosion. Concrete spalling is when the concrete face is pushed off due to expanding steel as a result of excessive corrosion/rusting. There is constant research going on now to find ways to protect the steel with additives mixed into the concrete during casting.
Wait what? Is this how that building on 9/11 fell apart ? Without warning?? 😭
@@Joelsmediahere no what the heck? it fell because a planed flew right into it.
@@Stephanie-gm6ue oh well I was referring to building 7 😅
@@Joelsmediahere huh?
The problem with the world trade center design was the outer wall panels and the floor joists. Once the central columns were compromised, the building lost its strength in the impact area and as the outer wall panels moved outwards the floor joists, that were supported by the wall panels, fell onto the level below. The design was to allow maximum open-plan office space without having columns everywhere. But the terrorists knew exactly where to hit to destroy the main central column.
Never in my life did I think concrete would be fascinating! Well done. Very impressed by pre-stressing - what a brilliant innovation!
Very simple and well illustrated explanation in a few minutes. Maybe i should recommend this video to some of my former lecturers (civil engineer here).
I work in residential construction. This is very good and interesting information for me. Thank you for putting these together.
"You shouldn't make rope out of concrete"
I rarely feel comfortable promising to take a piece of advice but this one seems easy enough to keep.
@San the Man Seeing this is like finding an easter egg in a video game
@San the Man lmao
Such a verbose expression instead of "Thanks for advice". I will save it for later use.
I teach a beginning Engineering Principles class. My students have been studying this exact topic for the last week. Tomorrow they are going to make small plaster beams that will span 1 foot. They will be able to add sand, rocks, fiber, glue, cable, wire, fiberglass grid, etc. They even have the choice between plaster of Paris or dental plaster. There will be 2 winners, the best strength to weight ratio and the best strength to cost ratio. I plan to use your videos for next year, keep up the good work. I will post a video of some of the student designs soon.
Also, if you are ever in the SLC area, I would love to have you as a guest speaker.
Love this comment
That’s so nice.
Here is the video of my students breaking beams. ua-cam.com/video/HchcobNa8AI/v-deo.html It is a long video due to lots of beams. You don't have to watch all of it to see how different mixes and reinforcement can change how strong it is and how it breaks. The record was 705 pounds.
This is an awesome video, thank you for the visuals!
Such an informative video, visual and auditory learning mixed w diagrams and stuff, absolutely perfect video, very interesting
Well done. Reminded me of the Hyatt Regency walkway collapse even though concrete was not at fault. As a city inspector/engineer I had to closely watch contractors who often didn't follow design specs, cut corners and lackadaisical engineers who verbally authorized changes without engineering reviews and change orders. Getting my life threatened by a unscrupulous contractor isn't fun.
Isn't it great, when some inadequate coward tries to feel superior, by threatening, lying. They are everywhere.
The Florida International University bridge collapse was an exact demonstration of these forces and failures.
Threat is taking it way to far that sob needs to be taught a lesson as to what happens if u do that
@@Eugenepanels the trouble is, the person handing out threats is the one who access to large holes that get filled with concrete, if you catch my drift.
I'm almost certain that these videos are aimed at a young audience but every video I see is captivating.
Lucky I don't have to do the hard number crunching that really makes things tick.
I've shared these with my daughter who is a Sophomore of Civil Engineering and she finds them very interesting and helpful despite their rather basic subject. It is a nice way of understanding what makes CivE and materials science useful.
Y u dont think can teach an old dog new tricks?
Informative, appropriately simplified and well explained. Nice! 🔥🔥🔥
Suddenly feel compelled to learn again. Excellent production.
What happens over time with rebar rusting and "vanishing" inside the concrete. I know today rebar comes with a plastic shroud to keep moisture out, but the nature of manufacturing causes nicks in the plastic. A fascinating picture I saw was in road construction from the 60' compared to days of road work; the amount of rebar in a raised road support than in now is 90% more.
I do enjoy your channel. Thank you for producing them!
Rebar generally doesn’t rust inside of concrete because there isn’t oxygen available for it to oxidize. Actually, the reason rebar usually is embedded about an inch inside a beam rather than it being on the surface, where it would provide the most benefit in terms of reinforcement, is because that 1 inch of concrete is meant to protect the rebar from weathering.
Like he mentioned in the video, the concrete has to crack for the rebar to have any effect, so when designing a beam like the one shown, the structural engineer actually ignores any capacity that 1” concrete cover may provide and uses the capacity of only the steel by itself, so it is actually purely to protect from things like weathering and fire.
@@Kdot19 I'm glad to see that there's people still out there that know about concrete.
@@alphaprecastconcrete5397 I had two classes on concrete and steel design this stuff was like carved into my brain lol
ua-cam.com/video/PLF18H9JGHs/v-deo.html
Steel can rust from the old practice of adding calcium to the concrete to cure the concrete faster.
The calcium eats away at the metal causing failure of the concrete.
Police officer: Help! I need reinforcement!
Steel manufacturers: hold my beer.
Hold my *rebar
Chinese rebar is like using play doh
i loveee your videos and the efforts you do to demonstrate them are sooooo appreciated for us learning online
Brilliant video. Thanks for sharing your knowledge and findings.
Hey, I have just started watching your videos. I am a building supervisor and commercial diver and I have really found your videos informative and easy to watch.
You have done such a good job of covering important aspects while not overloading with information given the relatively short time you have to explain a topic.
Awesome job
I would love to see more types of concrete in the next videos, like mixed with resin, fiberglass and others. Thank you for this series!
I don't know why UA-cam recommended this, but now I have new knowledge about concrete.
I did not expected this video to be so amazingly complete
Hey in not an engineering major or really care about the subject, but I love the way you explain these topics. It's super engaging and I actually find myself looking forward to learning and seeing what you have to say. Thanks Grady!
yeah right sophia
Sophia give me your social contact
Tell me sophia
Can you upload a detail leacture on foundation plan for steel structure
CIVIL WORLD bloody pervert
As you can see, this man is clearly an Engineer.
He solves practical problems.
I dont see him using gun tho
@@kamikaze3124 This problem doesn't NEED more gun tho...
@@radiobehemoth9334 there is no thing as enough gun
* me Proud as an Engineer“
@@kamikaze3124 That is true.
I do not know why this showed up on my recommended, I've never watched something even remote to this, but thank you, it was very interesting
Thanks for the video mate! Had a great time watching this with my dad!
I have money for a shirt that says "You shouldn't make rope out of concrete".
I second that! This shirt must be made!
There are so many good quotes from his videos my favorite is ""engineers generally try and avoid building civil structures out of liquids." From the quicksand video. I would love either of these on a shirt
Or "every time you say cement instead of concrete an engineer's calculator dies" this one in my favorite
I'd pay 100 bucks for it
"a length of strong cord made by twisting together strands of natural fibers such as hemp or artificial fibers such as polypropylene."
You're correct but for the wrong reasons. Way to go.
Congratulations on 500,000 subscribers! Your videos are awesome!
HJCF0520 On to the next 500,000.
I appreciate your efforts in the experiments. It was very interesting
Showing the sponsor ad at the end is what got you a new subscriber
My dad is a civil engineer, so I'm aware how much more you can talk on concrete! So many different recipes! And add ons for the concert! Also how important it is to use vibrators while casting!
to enjoy yourself while you are waiting ( ͡° ͜ʖ ͡°)
Maric well I wouldn't use the concrete vibrators for that... Unless you enjoy internal bleeding and being ripped to tiny pieces, then go ahead!
I've been a concrete finisher for two years now and this was very interesting to learn. Thanks.
I have never worked with conrete in my life, and it was still interesting to learn!
@@shen1801 if you do WEAR GLOVES! Over the years concreting has made my skin terrible
should I be concerned?
Your voice is soooooo soothing and relaxing, it's like i am learning while relaxing
Very good, well informed video. Nicely done.
Great work
ooke
i subscribed 2 you, now u hav 1.8 million subs
nice!
nm
A concrete comment. +1
The most interesting thing I learned about concrete when I got into carpentry is that concrete and steel expand and contract at the exact same rate, which is why steel reinforced concrete doesn't immediately crack. I never thought about it before they taught it in my apprenticeship but I found that interesting for some reason
@retsaM innavoiG well it's true buddy. That's why bridges and skyscrapers and shit aren't full of cracks. Roads are because the ground heaves but that's a different cause
Thanks for the video. I've heard that adding polymers to the aggregate can be an effective way to reinforce concrete, and in some applications can even replace rebar.
Love the content. Also, the background track is dope 👍
This stuff is really cool. I wish I learned about this type of thing when I was younger. Getting to see what everything around us is made out of makes the use cases of applied math and science very apparent.
I just got done learning how and where to space rebar in reinforced concrete in my theory of structures classes next semester. I love this so much
Very interesting, thanks for posting. I've often wondered about some of these things, now I know a bit more
If anyone is wondering pre tensioned slabs are reinforced with tensioned steel cables.
Also on reactive soils engineers tend to put 2 layers of mesh/rebar in. Bottom layer for the downforce of vehicles and a top layer to stop the ground heaving the concrete up from below.
Threaded rod is a terrible idea to reference Re-Bar.
Re-Bar is made from a mild, low carbon, high ductility steel.
This allows much more 'strength' from the metal, it has a longer durability for external and internal forces.
Meaning it can actually stretch before breaking.
Threaded rod is made from a myriad of materials, with my uses finding them in the higher carbon range.
Higher carbon content allows the threads to retain their shape and not stretch as much with normal torque levels usually required of them.
Much like bolts, which are mostly higher carbon.
Not only that but the sharp ridges formed or cut for the threads provide a very nice shear point allowing threaded rod to break with relatively very little force, Re-Bar, not so much.
Your video still shows the relation and still works well enough for most purposes.
But you did ask for what we thought, and this is my thought.
Rebar nerd!
Actually threaded rod is quite appropriate for a demonstration. Even the smallest size rebar (#3) is way too big for the size "beam" he was testing. I used a number of rebar models when I did a lot of model slab tests 50 years ago ranging from twisted strands of tie wire to threaded rods.
Are you going let DoctorLarry show you off ?
Is just makes the concrete more flexible rightttt
Settle down yall, settle down
I love UA-cam and am thankful for people like yourself that make these videos. I didn't realize how complicated concrete was.
I knew rebar was a reinforcement for concrete, but I never knew how or why it worked. This was very informative; thank you!
Nope. How come a long rebar which sags under its own weight be a any help for reinforcement
@@ashallama223 Did you even watch the video?
I can make video that can convince anything. This is a question to ask anyway.
Excellent demonstration,
Grady, thanks so much for all the prep work you do for your videos. I have learned so much!
When I was a child, my dad decided to add on to our home. He decided to use cinder block instead of reinforced poured concrete for our basement walls. (Rebar = reinforcing bar) Unfortunately, I spent the rest of my childhood bailing our basement out every time it sprinkled outside. The water sprayed through the cinder block like hundreds of shower heads. When it rained, my older brothers would run around with a pencil and circle all the streams to later go back and smear on this water proofing paste used specifically to waterproof cinder block. If you're wondering, no it didn't work.
Interesting. I don't know why YT recommended this for me, but it's quite interesting. The practical demonstrations are great. Great video.
Great and interesting, you really describe the behavior of reinforced concrete beam
Great video: instructive, clear and fun.
Great. NOW I see this. I just spent a fortune on concrete rope I no longer trust.
:'D
I'm civil engineer and still enjoying this video.
What do you mean "still enjoying it"? You would enjoy it more if you are a civil engineer.
are you able to produce the energy from atmospheric pressure by using a large scale android's barometer means big modal of android barometer ,say a kilometres diagonal large area could produce 27kilowatt energy per day
Hey what titanium rebarb in sted of steel?
Yeah.. You should
That's like saying, I'm a chef but I still like watching the Food Network...
Yeah...obviously.
Nice work. Very informative. Thanks.
Thank You for the Wonderful manner of explaining ! Thank You for your effort and Time !
I really appreciate your knowledge and that you are willing to share with those of use that don't have an engineering background.
Thanks.
You've answered questions about concrete I didn't even know I had. Great video.
I can't get enough of your content thank you
Thanks for sharing this information!