The actual reason for using stirrups explained
This video explains the reason why stirrups are installed in concrete beams. The video begins with a generic explanation of the bending and shear loads that beams are usually subjected to. Beams have different mechanisms for resisting these types of loads. Each load causes different types of stress whose combination presents a unique challenge. The explanation concludes with the crack development process and principle stresses that are key for the propagation of the crack.
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References:
[1] ASCE-ACI Committee 426, "The Shear Strength of Reinforced Concrete Members," Journal of Structural Division, vol. 99, pp. 1091-1187, 1973.
[2] S. Brzev and J. Pao, "Shear Design of Beams and One-Way Slabs," in Reinforced Concrete A Practical Approach, Toronto, Prentice Hall, 2009, pp. 260-315.
[3] J. M. Gere and B. J. Goodno, Mechanics of Materials, Cengage Learning, 2013.
[4] N. E. Dowling, "7 Yielding and Fracture under Combined Stresses," in Mechanical Behaviour of Materials: Engineering Methods for Deformation, Fracture, and Fatigue, London, Pearson Education Limited, 2013, pp. 275-333.
What I liked most about this video is that it didn't get too abstract or mathematical/numerical. I think you would loose a lot of interest if you deviate from the general concepts. Stirrups and "what they are really for" is fascinating for the curious viewer. I don't want to get lost on the path and exact trajectory of a crack. I'm actually also using this information now for an appraisal of a house I had built in an earthquake-prone area of Turkey over two decades ago, so this comes exactly at the right time. This video, like many of your others, is perfectly balanced. When I, as a layman, explain what I have learned here to a qualified engineer and he raises his eyebrows in astonishment and enlightenment (yes, this really happened) then I know you have done an excellent job 🙂. Thanks for the inspiration!
Comments like this is what makes it all worth it! Thank you!🙏
@@TheEngineeringHub İt's more than well deserved. And I forgot to mention the quality of the graphics, absolutely top-notch in my opinion, they make things so much easier to grasp. I can't imagine the amount of time invested to get these right.
Was this comment before or after the earthquake?
Agree 100%! Nothing makes me change videos faster like seeing lots of math and calculations
Being a civil engineer, and more specifically a bridge engineer, I have never come across a better explanation than this as to why engineers use stirrups in design. Theory in textbooks, lecturers in university, senior engineers as mentors post university, and none have explained it as clear as you have. Definitely got yourself a new subscriber! Well done on a great video!
Wow, so flattering to hear!! Thank you so much, FPLijah!
@@TheEngineeringHub It was a suggested video, and so glad I stumbled across it🙌🏼 Can't imagine how long it takes to make a video like this
@@FPLijahthe process is a bit time consuming but comments like yours make it worth it. I'd say between 50-100 hours of work which is the main reason why we post about once a month. It gets a bit too much with a full-time job as well.
@@TheEngineeringHub wow! Crazy hours of work! Honestly we appreciate the effort bro🙌🏼🔥
Disliked unsubbed
Students of nowadays will find it much easier to grasp complex concepts with audiovisuals like these than during my Civil Engineering undergraduate years just 20years ago. Our lecturers and most text books just makes the topics abstract and unrelated so therefore incomprehensible to most students. Now learning is fun like never before. Keep this up please!
I agree.
I wish there were videos like this back when I was a student. You've done an exceptional job explaining the necessity of stirrups - both verbally and visually.
Thank you for the nice words, Dushan. Svako dobro, pozdrav!
Which country are you
I’m not an engineer but I work as a roadway inspector and a lot of my work is on construction of new bridges. We make sure the bridge is built according to plans and specifications. If something minor or large is changed we have to go thru the licensed engineer on site. These videos help me understand the details of bridge plans. Well done!
That's amazing, thanks Joshua. In engineering and construction, small details could make a significant impact on the load-carrying capacity of the structure. Often, this is not too obvious and people may tend to ignore small changes but for example, installing fewer stirrups at the end of a beam could have disastrous effects. Thanks for the discussion, cheers!
Aviation works in a similar way. A DER does the design, a DAR makes sure that it's built that way. Both are crucial functions.
@@lautoka63 I’d love to get in the aviation field. Hard nut to crack without any experience or knowing someone in the field to bring you in.
In addition to this, stirrups also provide ductility. This is really important for strengt and design. Not only shear force resistance but also ductility
why is V_dowel ignored?
I agree, stirrups prevent buckling of longitudinal bars in the compression side, letting yielding of bars in the tension side.
i wish my uni lectures were like this, so clear and concise. i'm very impressed, thanks for the video!
My friend that is brilliant work from your side.... i usually watch engineering videos and this recommendation came right off.... i had watched only half way through before i paused and Subscribed... brilliant..
Thank you so much chapad, we are very glad to have you as a subscriber. Stay tuned, more videos are on the way!
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@@TheEngineeringHub I'm subscribed and turned on the bell
One of the best descriptions I have ever seen of basic reinforced concrete engineering. Particularly for non engineers like me. Anyone in building and construction As well as civil construction would benefit from understanding these things. Keep it up.
Very interesting. I've worked in concrete for almost 20 years now. Thank you for this information .
That's awesome JareDevilDog. Glad that you found it interesting, did you also know the reason or was this new? Regards.
@@TheEngineeringHub I didn't realize that was the reason. Your channel is very informative.
As a student in the field of engineering this explanation is most important.
Extraordinarily clear, easy-to-follow explanation. This guy is a BORN pedagogue.
WHOAH! MAN that's out of line! Do you have proof hes attracted to minors?
@@nolesy34 A pedagogue is someone who is good at pedagogy, that is, teaching. I see that it can sometimes be seen as a teacher who is "too strict" - in my case, it is meant purely as a complement. NOT pedophile. So now you've learnt a new word!
@@blixten2928 oh.... Oooooooh
This video is better at teaching than most of the engineering teachers at the engineering university. Thx bro
Thank you for that interesting video: NO background music, very good explanation. Brilliant!
Mate, thank you very much for making such a good, informative videos. I wish University professors do such simple, yet brilliant approach to explaining. You're awesome.
University 100,000 debt KZhead videos Free Fake engineering credentials Collapsed building Jail Priceless
This is what we call next level of explanation 👌
Thank you Ajmal, your support is very appreciated!
Great video. Maybe you could add another one explaining the differences between pre-stress and post-stress reinforcement, and an example of why an engineer would choose one over the other in real-world application. Basically which to use and why. Thanks for the video! The cross section of normal vs. shear stress really provides a great visual understanding of how they differ and the result of each force on a beam.
Great suggestion and thank you so much for the feedback PA Mike, much appreciated!
When you say pre-stress, do you mean pre stressed cables within a beam instead of rebar?
why is V_dowel ignored?
@@davidrn2473 Pre-stressed beams generally have both cables and rebar. But yes, the cables are stressed within the casting form and then concrete is poured and allowed to cure. After the form has been stripped and the cables cut from their stressing anchors the beam can take on a significant bend.
Wow great job explaining this. Even showing the principal stresses.
Thanks Neil, hope you enjoyed it!
Just WOW! Every line of the video is to the point and explains shear very well.
Thank you for the feedback and nice words Raghav, much appreciated!
@@TheEngineeringHub why is V_dowel ignored? care to explain please?
What a lovely video and calm voice! The explanations are wonderful and a real treat. And the graphics,… I mean WOW!
thank you.I have been looking for exactly this explanation of why stirrups are concentrated nearer the ends of beams and some columns
Yes, that is exactly the reason. Stirrups resist the shearing forces that are usually the highest near the supports. Most beams do not need stirrups near the mid-span due to the low shearing forces that can be resisted by the concrete alone. When it comes to columns, the shear forces are actually constant along the length of the column. However, the ends are exposed to higher bending moments. The closely spaced ties in columns are usually installed to provided additional ductility and prevent spalling of the concrete in the case of an earthquake.
I will look forward for more of your videos Sir. Your discussion was very systematic and visual. It helped me a lot.
Awesome, thank you!
Never thought past the obvious reason for stirrups. Learn something new every day. Thanks. Great comments.
Excellent video, I was so excited to like before finishing it hope you make more!
I think this is the best visuals of showing the various forces, and why they occur. Way better than I got at uni (though that was nearly 30 years ago). And I subscribed.
I’ll have to bookmark this. Very informative!
I've an interview coming and couldn't asked for any better time to come across such a channel. keep up the good ma man.
Wow, this was fantastic, thank you! I had no idea so much was involved, or how they calculated what stirrups to put where.
Good video! It may take a while before one goes viral, but when that happens people will watch all your old videos too. It's nice to see diagrams designed specifically for this topic instead of stock footage.
Thank you so much Nathan! We spend a lot of time designing diagrams that can communicate the message as clearly as possible. We haven't had huge success yet but we will just keep working and hoping to reach as many people as possible. Cheers
It is viral now
The work and dedication that went into these videos really shows.
Thank you for the name of the further research topics. I will look up stress transformations as a refresher for sure
This is absolutely brilliant so glad I found this channel🙏
Incredible work! I really loved the visualizations! Best regards from Germany 🙋♀️
JA JA
Very well done! I am grateful for your efforts.
This video communicates the concepts so well. The animations are great.
Thank you again Prando
Thankyou this is really what i called an explanation with example & simplicity.
Congrats on creating I Love Engineering! This is such an amazing initiative, helping bring engineering closer to the public. As an engineer myself, I can totally relate to this and appreciate the effort that goes into engineering projects. The videos, resources and content make it all the more enjoyable to learn and explore engineering. Whether you are just starting out or just simply interested, I Love Engineering will help open your eyes to the limitless possibilities of what is achievable in this field. Keep up the excellent work!
Good content! I have a little story about concrete bridge spans (I'm not an engineer, so if I label something incorrectly, that is why). I never realized that concrete bridges flex downward (so much) when under load... (Story) I had completed my weekend National Guard drill in El Paso and was on my way back eastward. I still had my uniform on and I decided to pull over and find an obscured place to change into my civilian clothes. I stopped at a dry creek with a bridge across about 10 feet...I went under the bridge and did my thing...I could certainly hear the vehicles crossing overhead and for some reason I put my hand on the underside of the bridge when some vehicles crossed...I could actually feel the span of concrete flexing downward every time a vehicle crossed. Realize that this was a high speed highway (75mph). I understood that there should be some measure of flex, but I never realized it was to this degree. Of course, while driving, you never really notice the dipping action of such a bridge.
Thanks for the interesting story Glenn! It is fascinating how flexible these structures can be. The flexibility is especially pronounced because they tend to be much slender than buildings (long but not as thick). Bridge deflections are usually limited by code to a value between 1/800 to 1/1000 of the span (depending on type, use, material etc). This means that a span of 30m (100ft) can (allowably) deflect up to 300mm (1ft) which can be scary to observe. This may get further increased if the bridge is not properly maintained and has cracked or deteriorated concrete i.e. loss of stiffness.
Well explained along with great visuals. Love this.
Thanks. Watching this video has been a very educational journey.
Could you please discuss alternative concrete reinforcement, such as fiberglass, basalt, stainless steel micro, bamboo, etc.
Dude, you did a really great job explaining this important yet neglected concept (specially in undergrad level). Really appreciate the video! Excellent breakdown.
Thanks for the compliments S O, really glad you enjoyed it!
Excellent explanation. One of the best.
Thanks for sharing the concept very clearly. Really appreciate to make such a civil engineering related video in further. Thanks again.
Thats yhe best video on shear force and principal stresses on the internet
Excellent presentation. Thank you.
Good info. Quite worth a reader with good speach!
Good Video. You forgot to mention couple of other functions of stirrups, f.e.: In columns - holding together compressed reinforcement, especially during fire (buckling) -improvement of the anchorage conditions -Increase steel and concrete cooperation as a whole
thank you very much for your effort you have given us many information about concrete and stirrups.
Our pleasure!
Thank you for the informative video. It will definitely helps for the upcoming midterm. Cheers mate
Good luck with your midterms British, but don't forget to also study and not just watch KZhead videos 😄
Great video: clear and concise!
Thank you Michele, we are glad you found it informative!
Excellent mate. Thanks for summing it up for me.
Such a great informative channel
Definitely got my attention. Precise and well explained. Subscribed!
Thank you 🙏
Excellent content
This is top notch explanation 👌
as a viewer, these types of videos always bring gratitude to the creators. there are tons of videos for technology, and architecture-related courses. perhaps civil engineering has less amount of interesting videos compared to others. it's an engaging video with theoretical explanations of real-life situations. wish to see more civil engineering and construction-related video from you
Hi Division by Zero, thanks for the nice comment!. More videos are on the way. In meanwhile, we encourage you to check out some of our older content. Cheers!
Thanks for the information in this vido and in others.. Just a note - minute 6: even upon considerable crack opening, the compression zone contribution to the shear resistance is minimal. Even though a compressive stress increases the shear strength, equilibrium does not throw much shearing stresses to the compression zone.
This is a _damn_ good explanation.
introduction ! man that was brillliant , great job
Thank you Bilel!
Excellent and clear explanation of this important and commonly misunderstood failure mode. They also act to confine concrete against bursting in columns. You might want to look at your annotation at 8.19. Best wishes.
Great explanation and great effort you have sir. Make video on bond stress , lap length and development length.
So well done - bravo!
Gonna have to subscribe. My job consists of me bidding for rebar on projects. So understanding how things are done in the field is always useful.
Extra ordinary work.
Very good explanation. So helpful and interesting.
Glad you liked it
Thank you sir. The content was very informative.
Thank you for putting so much time and effort into making this video which has lucid explanation. That's how so many complex concepts becomes a peace of cake. A great video showing textbook diagrams in practical scenario. Thank you for saving my time. Love from India. ❤
Thanks Deepak, we are so glad you found the video useful. Stay tuned for more intuitive explanations of engineering topics. Cheers!
@@TheEngineeringHub Yup. I started exploring your channel and found so many videos like this one. May I suggest a few topics in due time so that you can explain them like this ?
@Deepak-pi9xx Yes, please! New suggestions are always welcomed
Very high Quality Content. Thank you, subscribed!
This is extremely well produced and informative, thank you for your high quality work!
Thank you Neuro for taking a second to give us feedback. We appreciate you!
Ooo I like this how steel and concrete works. Also the psi in concrete plays great role in structural design.
Amazing! ❤
Hats off man....subscribed to this worthy channel
Much appreciated Arun, stay tuned for more!
Brilliant Job brother. 🙏✔️👌
Amazing video!
Very well explained, very educational.
Thank you Cesar!
Awesome stuff!
I'm retired and living in a third world county (Mexico) where as the over whelming vast majority of homes have concret roofs. In the past prior to the advent of using rebar, The various rooms within a home had to be a certain size or the span of concret aka roof above would fall in. Which was most generally in those days the equalivent of two inchs. Today using rebar a 1/4 in in diameter, if and when sufficent rebar is implemented, a roof can span a larger area, thus the sizes of room beneath it are now larger. If and when one thinks ahead and there are plans someday to adding an additional room or rooms above the original. If and when the first level has no rebar or only a 1/4 of inch rebar. The floor above which is the roof below. Will agian fall in. Thus the one who buys a house when it was built using no or 1/4 in rebar and isn't aware of it when they personall elect to increase the size of their home to include a second livng area above the first. Have issues with the roof aka floor above, falling in on them. But by then as allways in Mexico. Once purchased, it's the owner issues. Not the contractors. I should add that there are repitable constuction contract who build homes. But the cost of them doing it vs someone who's agenda is to just build one as cheap as they can and make the same money as the more expensive contractor. Will sell for nearly 25 percent less. Which allows them to build more houses because who wants to pay 25% more for what appears to be the same house. In the U.S.A. what is referred to as town houses or quad homes; And not houses. Are built with one wall between two adjoining homes just like apartment complex's do. In Mexico and assumable other third world countries. The homes built adjoining others some times twenty in a row. Though there is only one wall that separates one from the one adjoining. They are still referred to as houses.
Nice video. I want more.
Amazing explanation 👏
Thank you!
That is most comprehensive video on this topic, we need similar video on column footing, also choice of shear and moment connection? We also need to know the action of masonry or wall under loads if you can.
Very informative and conceptual video. I liked it very much. Pls keep uploading such animated videos as it clears many doubts RCC and SOM
Doubts of RCC and SOM*
Thank you Prashant, more videos are on the way, stay tuned! In meanwhile, feel free to check out some of our older videos, cheers!
One could start to wonder why we put concrete anywhere where it will be under tension. Its function there appears to be little more than holding the rebar in place, and protecting it from corrosion.
You are not wrong Sylvia. The reasons are probably more practical than technical. Building forms in a rectangular shape is much more cost effective. For some other places, like an internal column that could bend in any direction, the tension forces just can't be avoided. Thanks for the insightful comment, cheers!
In many applications, I think the truss would fit bill much better. Protecting the steel from corrosion can be achieved through paint coating.
That is very important concept. I would always wish that to understand from my teacher but he would have not abled to satisfy me. But I watched this video 4 to 5 times and I feel very confident.
again, great video. keep up the good work
Thanks, we will try!
Thank you sir..this video's are great..🤩💪
Awesome video! Thank you!
fantastic stuff very interesting
As a former cement guy who tied more than his fair share of steel back in the day, I always thought the verticals were to hold the horizontals in place while the concrete was being placed.
thanks always informative content 👍👍👍👍👍
you are great man. I liked your video.
Boss tnx for sharing the beams and concrete tnx again god bless you and your family
Our pleasure!
Exactly!! And also, torsion and confinement
That is brilliant man, being a teacher i really appriciate your efforts, n subscribed your channel
Thank you so much Muhammad. Your support is very much appreciated!
Great job .
Thank you sir!
very informative
Great video
Easiest to understand indeed !!
This was absolutely brilliant and very helpful, thank you so much! I'm so glad KZhead recommended a video from this channel
Brilliant video, and we'll explained
Excellent presentation ! Thnx !
So nice of you, glad you liked it!