Thank you And I mean it I love how you explained it I'm just subbed This is my first time ever taking the time to comment but you deserve all my time to give you all the good words. Love you
Thanks for this video. Never thought the placement of the rebar is also crucial. I thought, just put it in the concrete, then it is reinforced. Actually, there is a proper method for it! Thanks a million!!!
Hi Mate, thanks for your comment, Yeah, there is quite a bit of science and calculation that goes into not only the placement but the size and number of bars etc.
Hey i think its a great video but saying steel is not strong in compression is misleading, steel is strong in both compression and tension. I agree that the slender reinforcement members will buckle but they were intentionally made slender for the purpose of reinforcing the concrete members.
What he probably meant to say or should've said was steel IS bad under compression in keeping it's original form and concrete is NOT...because the bond in the molecules of steel deform and create new bonds under compression which weakens the overall form/shape while concrete keeps its original bonds under equal or greater loads.
aaron mitchell Your words are right but the explainer wasn’t wrong though. There is no such a perfect strength of steel at compression. It’s actually deteriorated. That’s why engineers don’t use steel in the applications of high compressive loading because they don’t know when it will possibly fail and at what stress value. check wikipedia, compressive strength
You also reinforce concrete, not to just make it stronger but it inherently makes the construction process cheaper as you need less materials to get the same strength
The next challenge: You have a concrete suspended floor poured between four walls. Over the years as the suspended floor is subjected to various stresses, it develops lots of tiny cracks - but they're not a structural problem because it's correctly reinforced with steel. Then you realise that all these tiny cracks represent a significant enlargement of the wall-to-wall dimensions of your floor, and it's distorting the outside walls holding it up. Then what?
if concrete bars are very strong when compressed, why do we use reinforcement is concrete columns. The concrete columns are only compressed aren't they?
Hi Parsi While columns are mainly in compression due to the weight of the building above they are still subjected to side ways forces which will place tension forces on the columns therefore requiring reinforcement.
I have a question that really bothers me. How does the compression on top of the beam work? I see that the arrows are facing towards each other from the sides. How is it being compressed? Where does this compression come from?
Hi Mate, the compression is created by the load on the beam. The load is trying to push the beam down while the supports are pushing against the load. This imparts the forces into the beam. Hope this helps
3:53, this reinforcement would more than likely be designed as a "two way" slab...They would have, more than likely, continued the lower reinforced steel out, over the "overhang" / cantilever. As it is now, this has a high chance of failure under load... Typically, cantilevers get designed as a two way...(load design)...(had to edit post as my phone's auto correct changed wording-it happens).
What is a general rule to use or not to use reinforcement? What good is the PSI strength if reinforcements must be used? Does 6500psi means it can handle a lot of weight? Thanks
Hi Mate, as a general rule I always use reinforcement. As for the strength it really depends on the use of the concrete in the end and should be designed by a Structural Engineer.
Hi Mate, agreed however the dimension that we use for reinforcement will deform easily under compression and therefore not provide any compressive resistance to the concrete.
Sad part is that my teacher used this animation as evidence that concrete beams can bend, without cracking or breaking, mind you... Shame an educational video didn't educate a teacher, but that says more about my teacher than anything else.
Hi Mate, that is unfortunate to hear. The bending in this video is grossly exagerated to make the movement and the effect stand out. While the slab or beam can "bend" or prehaps better called "flex" it would be such a small amount that it would not be visable to the human eye and almost always result in cracking.
So your example has nothing to do with the vast majority who only use concrete for slabs which are not suspended but rather supported by the earth underneath them. In that case what would be the reason to use rebar? And in case you reply with load bearing walls those are generally further supported by a deeper footing under those areas. Thanks for the reply.
Hi Mate, Even slabs on the ground have footings and as the soil is prone to shrink away from under the slabs they are still designed as if the earth is not there. Effecively the earth is only a formwork. In extreamly reactive soils you may get the ground moving and pushing up on the slab, in these cases extra reinforcework may be needed in the top of the slab to counteract these forces. The point of the video was to show how the reinforcement works to strengthen the concrete and how we can be economical with its placement so we are not just filling the entire slab up where it is not needed. This is really the role of the structrual engineer to work out where the reinforcment is going to be required. Hope this helps.
Hi Buildsum. My plumbers have cut a 300mm channel through a concrete bathroom floor to take the waste pipe/drain etc. In regard to filling this back in, would you use steel mesh and rebar drilled in to each side of the cut walls of the slab or just steel mesh? Thanks for all the great videos and detailed explanations.
Hi John Have they cut out any reinforcement when they cut the channel, if not then all good just fill it in with concrete. If they have cut out reinforcement then I would want to replace it, rebar or mesh would work as long as you can drill it in on both sides and epoxy it into place. Basically, it just has to be equivalent to what was there in the first place.
Hi Arran Thanks for your kind words. I was a licenced builder but no longer run that business, i have been teaching Carpentry and Building for the last 10 years in Sydney
You are welcome mate, you are very noligable in construction. I am in the process of getting my building license so these videos have been great as a refresher for work I done years ago. All the hard work I have been doing to try and get my building license... I feel as though anyone who has or had a building licence have lived the dream!😊
i appreciate with what you tried to explain in this video.. I'd only like to add that steel bars have same strength fy in tension as well as compression.. buckling is another thing.. that's why in columns steel is also used to increase their axial load carrying capacity apart from the unbalanced moment induced, but main force is axial in columns.. So steel are both used in tensile as well as compressive reinforcement depending upon the members of the structure..
Hi Bobby, yeah I have had a bit of a problem with the audio on some of the videos which I think I have got sorted in my latest videos but no one has mentioned this video before, thanks for letting me know.
Concrete buckles in roads and footpaths where there is not enough allowance for expansion. As it sets concrete "grows" and if it is adjacent or confined in an area it will apply pressure on those surrounding objects.This can be overcome by using expansion joints. ruclips.net/video/P29HjxvOitM/видео.html Hope this helps
yes it does...sorry for not being specific....the concrete under tension does not buckle and crack because of the compression....to give an example is upon curing the concrete I have worked with is cooked to a temperature of 145 degrees f without tension and then the ends of each panel or pile are cut thus producing tension and closing each fracture or crack....the rapid heating and cooling of concrete or extreme heating of concrete (not under tension/compression) will crack
I think this a great video for simplifying the issue. As for the detailed explanation from the engineers, if this video was to get into all that, the nature and the audience of the video would have to change.
Hi Benito, yes mate, steel is strong in compression and tension however long thin lengths like those used as reinforcement will deflect and bow when put under compression and as such fail to do the job.
I love your videos, they are very useful, and the imaging work you do makes the explanations clear and simple. Thank you! However in this video you said something I know to be wrong "steel is week in compression". It's just not true. Try compressing a cube of steel under a press sometime! According to structural properties steel is approximately equal in compression and tension. However, if you draw out long thin shapes, like steel re-inforcing mesh, or steel rebar, then yes, in those shapes it deforms under compressive loads. This is where the combination of steel inside concrete - which stops it deforming - makes the end result much stronger in compression and tension at a very reasonable cost (building in steel only is too expensive lol). Massive ships like oil tankers are built in steel and have enormous compression loads on various parts under sea states like big waves but do fine without alternative "strong in compression" materials as the member shapes aren't long and thin like rebar / mesh.
Hi Mate, Yes i agree, perhaps I expressed it the wrong way, I should have said something like "steel in the form that we use it will deform under compression" but I hope it still gets the point across about how the steel completments the concrete to form strong building elements.
Beautiful explanation, sir! Everyone else explains how to install but not the simple physics/engineering of it all! Thank you!
Thanks Mate, Glad it was helpful!
Thank you
And I mean it
I love how you explained it
I'm just subbed
This is my first time ever taking the time to comment but you deserve all my time to give you all the good words. Love you
Hi Mate, thanks for Subbing, I'm glad you are finding the videos useful.
Thanks for this video. Never thought the placement of the rebar is also crucial. I thought, just put it in the concrete, then it is reinforced. Actually, there is a proper method for it! Thanks a million!!!
Hi Mate, thanks for your comment, Yeah, there is quite a bit of science and calculation that goes into not only the placement but the size and number of bars etc.
Very nice
thanks
just subbed
Thanks
So interesting and useful details
Thanks Mate, I'm glad you like it.
Hey i think its a great video but saying steel is not strong in compression is misleading, steel is strong in both compression and tension. I agree that the slender reinforcement members will buckle but they were intentionally made slender for the purpose of reinforcing the concrete members.
Fair point Aaron thanks for you input.
aaron mitchell I also commented the same above.. you can see my comments and explanation I wrote.
What he probably meant to say or should've said was steel IS bad under compression in keeping it's original form and concrete is NOT...because the bond in the molecules of steel deform and create new bonds under compression which weakens the overall form/shape while concrete keeps its original bonds under equal or greater loads.
aaron mitchell
Your words are right but the explainer wasn’t wrong though. There is no such a perfect strength of steel at compression. It’s actually deteriorated. That’s why engineers don’t use steel in the applications of high compressive loading because they don’t know when it will possibly fail and at what stress value.
check wikipedia, compressive strength
Thank u very much sir....
very nice explanation of animations...
I will never ever forget this in my life...
GOD BLESS U SIR
HI Jagdish
Thanks for your very kind comments, I hope they help.
Really nice video!! You just cleared my concepts :)
You also reinforce concrete, not to just make it stronger but it inherently makes the construction process cheaper as you need less materials to get the same strength
Hi Bryran, great point, thanks for your comment.
Great explanation, well done!
Thanks Mate, Glad you enjoyed it
Now I know the why.
Thank you !
Thanks Mate
The next challenge: You have a concrete suspended floor poured between four walls. Over the years as the suspended floor is subjected to various stresses, it develops lots of tiny cracks - but they're not a structural problem because it's correctly reinforced with steel.
Then you realise that all these tiny cracks represent a significant enlargement of the wall-to-wall dimensions of your floor, and it's distorting the outside walls holding it up.
Then what?
if concrete bars are very strong when compressed, why do we use reinforcement is concrete columns. The concrete columns are only compressed aren't they?
Hi Parsi
While columns are mainly in compression due to the weight of the building above they are still subjected to side ways forces which will place tension forces on the columns therefore requiring reinforcement.
Because to protect against earthquakes, storms, slight misconstruction, and as always the drifting of the angle of ground plane.
sir Thank you for clearing my concept.....
make more Video like this !!!!
I have a question that really bothers me. How does the compression on top of the beam work? I see that the arrows are facing towards each other from the sides. How is it being compressed? Where does this compression come from?
Hi Mate, the compression is created by the load on the beam. The load is trying to push the beam down while the supports are pushing against the load. This imparts the forces into the beam. Hope this helps
@@Buildsum Thank you so much! I'm still studying high school I'm trying to learn some basic knowledge about civil engineering.
Very helpful to clear the basics..thanks a lot..
you should've put the longitudinal bars below the transverse bars for bottom reinforcement. that's the proper way of laying out rebars
***** Thanks for point that out Kevin
Makes f all difference kev
the 32,000 lb stress per cable x 12 greatly increases lateral strength.....
3:53, this reinforcement would more than likely be designed as a "two way" slab...They would have, more than likely, continued the lower reinforced steel out, over the "overhang" / cantilever.
As it is now, this has a high chance of failure under load...
Typically, cantilevers get designed as a two way...(load design)...(had to edit post as my phone's auto correct changed wording-it happens).
Hi Mate, thanks for your expert comments, good to know.
Buildsum, your welcome... keep up the videos.
What is a general rule to use or not to use reinforcement? What good is the PSI strength if reinforcements must be used? Does 6500psi means it can handle a lot of weight? Thanks
Hi Mate, as a general rule I always use reinforcement. As for the strength it really depends on the use of the concrete in the end and should be designed by a Structural Engineer.
Steel is very strong in both tension and compression and therefore has high compressive and tensile strengths.
Hi Mate, agreed however the dimension that we use for reinforcement will deform easily under compression and therefore not provide any compressive resistance to the concrete.
Awesome vid mate. Simple and easy to understand
Thanks, Mate, Glad you like it
in my experience with the prestress panels versus the # 11 rebar reinforced panels....the prestress are much stronger by about 2-3 times
Thanks for explaining this. Appreciate it!
No Problem Eduard, glad you like it.
Sad part is that my teacher used this animation as evidence that concrete beams can bend, without cracking or breaking, mind you... Shame an educational video didn't educate a teacher, but that says more about my teacher than anything else.
Hi Mate, that is unfortunate to hear. The bending in this video is grossly exagerated to make the movement and the effect stand out. While the slab or beam can "bend" or prehaps better called "flex" it would be such a small amount that it would not be visable to the human eye and almost always result in cracking.
Great video I really learnt about concrete reinforcements
Thanks Dogle
So your example has nothing to do with the vast majority who only use concrete for slabs which are not suspended but rather supported by the earth underneath them. In that case what would be the reason to use rebar? And in case you reply with load bearing walls those are generally further supported by a deeper footing under those areas. Thanks for the reply.
Hi Mate, Even slabs on the ground have footings and as the soil is prone to shrink away from under the slabs they are still designed as if the earth is not there. Effecively the earth is only a formwork. In extreamly reactive soils you may get the ground moving and pushing up on the slab, in these cases extra reinforcework may be needed in the top of the slab to counteract these forces. The point of the video was to show how the reinforcement works to strengthen the concrete and how we can be economical with its placement so we are not just filling the entire slab up where it is not needed. This is really the role of the structrual engineer to work out where the reinforcment is going to be required. Hope this helps.
Hi Buildsum. My plumbers have cut a 300mm channel through a concrete bathroom floor to take the waste pipe/drain etc. In regard to filling this back in, would you use steel mesh and rebar drilled in to each side of the cut walls of the slab or just steel mesh? Thanks for all the great videos and detailed explanations.
Hi John
Have they cut out any reinforcement when they cut the channel, if not then all good just fill it in with concrete. If they have cut out reinforcement then I would want to replace it, rebar or mesh would work as long as you can drill it in on both sides and epoxy it into place. Basically, it just has to be equivalent to what was there in the first place.
Thank Buildsum. They have cut the mesh out, so I will use rebar, as suggested. Thankyou for the quick response, as usual! John
great video. thank you for the explanation
Thanks Zac, I'm glad you like it.
make video showing BM and SF in all the structural elements. please.
Hello Mate,
I would like to thank you for your time in making these great videos!
Are you a builder or surveyor?
Hi Arran
Thanks for your kind words.
I was a licenced builder but no longer run that business, i have been teaching Carpentry and Building for the last 10 years in Sydney
how do you retstore the. Timber on my my. My work mate
Orpkmatete
This looks exactly like what happened in FIU florida
Very informative. Thank you
Thanks, Neo, Glad you like it.
You are welcome mate, you are very noligable in construction. I am in the process of getting my building license so these videos have been great as a refresher for work I done years ago. All the hard work I have been doing to try and get my building license... I feel as though anyone who has or had a building licence have lived the dream!😊
Thanks for this great Video....
Thanks, Kendis, I'm glad you like it.
i appreciate with what you tried to explain in this video.. I'd only like to add that steel bars have same strength fy in tension as well as compression.. buckling is another thing.. that's why in columns steel is also used to increase their axial load carrying capacity apart from the unbalanced moment induced, but main force is axial in columns.. So steel are both used in tensile as well as compressive reinforcement depending upon the members of the structure..
Thanks for your input Mohamad much appreciated
Thank you very much 👏
No problem 👍
Sir!! Which software you used make this animation?
Sarang Essa Hi Sarang I use Google Sketch Up for all of my drawings
thanks bro , really nice tutor....keep it up!
thanks you so much for this video ^_^ very useful in my report :D
+maria avenida “manet” Olaguer Thanks Maria hope you do well with your report.
+Buildsum very informative video. common sense for you and I. but you explain things very well
Volume output is very low for some reason
Awesome video
Hi Bobby, yeah I have had a bit of a problem with the audio on some of the videos which I think I have got sorted in my latest videos but no one has mentioned this video before, thanks for letting me know.
with about 1/8 inch of compression per 10ft....with 7 strand twisted cable.
...strong stuff
its cool and so easy.
Thank you.
good presentation
Thanks dear ❤
Unfortunately it buckles in extreme heat when used as a road
ExoticSpeedify the heat will not affect the prestress panels with any noticable difference
Jonathan Carnahan How come on the highway we get buckles?
Concrete buckles in roads and footpaths where there is not enough allowance for expansion. As it sets concrete "grows" and if it is adjacent or confined in an area it will apply pressure on those surrounding objects.This can be overcome by using expansion joints.
ruclips.net/video/P29HjxvOitM/видео.html
Hope this helps
yes it does...sorry for not being specific....the concrete under tension does not buckle and crack because of the compression....to give an example is upon curing the concrete I have worked with is cooked to a temperature of 145 degrees f without tension and then the ends of each panel or pile are cut thus producing tension and closing each fracture or crack....the rapid heating and cooling of concrete or extreme heating of concrete (not under tension/compression) will crack
Thank you so much for this video! It is really helping me on writing my theory on "Earthquake Resident Buildings in the Future".
Thanks, Kaylee, wow I am constantly amazed by the range of people who find these videos useful.
Thank you for making this, very informative and helped me in my report!
Go to he'll
Thanks i will reinforce my tea biscuits so they will not fall in tea
good vid fam
thanks
Program?
ShetchUp
Nice
Thanks, Glad you like it.
Audio needs to be louder
SIngh turn yer volume up init
BTW the tofu that you make is delicious I love it
great!
Cool explanation.
One question. Can you do a visual tutorial about the importance of rebar under a bearing plate in block masonry?
I think this a great video for simplifying the issue. As for the detailed explanation from the engineers, if this video was to get into all that, the nature and the audience of the video would have to change.
Thanks, Shiva, the idea behind this video was just as an introduction to the concept, thanks for your comments.
love from india
stell is strong in any way
Hi Benito, yes mate, steel is strong in compression and tension however long thin lengths like those used as reinforcement will deflect and bow when put under compression and as such fail to do the job.
O
I love your videos, they are very useful, and the imaging work you do makes the explanations clear and simple. Thank you!
However in this video you said something I know to be wrong "steel is week in compression". It's just not true. Try compressing a cube of steel under a press sometime! According to structural properties steel is approximately equal in compression and tension. However, if you draw out long thin shapes, like steel re-inforcing mesh, or steel rebar, then yes, in those shapes it deforms under compressive loads. This is where the combination of steel inside concrete - which stops it deforming - makes the end result much stronger in compression and tension at a very reasonable cost (building in steel only is too expensive lol). Massive ships like oil tankers are built in steel and have enormous compression loads on various parts under sea states like big waves but do fine without alternative "strong in compression" materials as the member shapes aren't long and thin like rebar / mesh.
Hi Mate, Yes i agree, perhaps I expressed it the wrong way, I should have said something like "steel in the form that we use it will deform under compression" but I hope it still gets the point across about how the steel completments the concrete to form strong building elements.
vgui
I sure u r steel bar structure not strong 💪
Thanks
Thanks Sam, I'm glad you like it.
love from india
love from india
Thanks, Pawan, Glad you like it.