RC Beam Design EC2 - Worked example - design shear reinforcement

[@sulaimansamatar4459]

You should have more than 5.2k subscribers. Your channel is very useful and fantastic.

[@ransfordaddai1740]

Yeah you are right. But the truth it, engineering channels don't get subcribers

[@muyomba12]

Thank you very much, your explanation is so easy and nice to follow! What seemed to be rocket science is so ease with your explanation.👊🏿

[@masouddelghandi7066]

Mr. Bather, your knowledge is verry usefull for us. I really look forward beeing thought about anything within this industrie by you. Thanks a lott !!!!

[@DailyMustafa]

Thank you.

[@sidj3018]

Hi Mike when does it occur that you need to have less spacing at the support and more spacing at the mid span, because there is more shear force usually at the support? So can I ask why you used the same spacing throughout ?

[@mikebather]

Hi sid j, that is a good question. I needed to keep the length of the video short for YT. You are right, what is proposed is conservative but, where shear is relatively small (around mid-span) we should check to see if we could reduce shear reinforcement to the minimum. This gives the designer a little extra work but reduces materials and so reduces the carbon footprint. Thanks, Mike

[@derekc5390]

thanks Mike- very clear tutorial

[@mughtarpetersen9981]

Clear, concise explanation.. Thanks!

[@alexphang3484]

Dear Sir, I enjoyed watching your lecture video and help me to understand how to use the codes effectively. If I may make a small request, is there any possibility that you can upload video to show how to design flat slab too...

[@steel6322]

This video has an amazing ratio of "likes" to "dislikes".

[@superjackhamm3]

Hi Mike, Great stuff ! Been using your examples to revise from. I see you haven't made anything over a year but a design on a skewed slab [I suppose showing the difference between orthogonal and skewed reinforcement] would be amazing to see. All the best.

[@tallettm]

13:20 killed me... In all seriousness though, great video!

[@SirKombabomba]

the video is really really helpful-thankyou

[@danflorea2815]

Hi Mike, thank you for nice lesson. Don't have one problem with concentrate force? Thank you.

[@mikebather]

Hi Dan Florea, thanks for the comment. The example is of a beam supporting a UDL which causes bending and shear. A beam that supports a point load (or concentrated load) would also develop bending and shear forces. Once these are determined, the bending design goes along the same lines Just be careful with shear and think through how this will develop in the section. I hope this helps, Mike

[@danflorea2815]

@@mikebather Thank you very much Mike. I wish you all the best.

[@somesh2745]

Very sincere lecture indeed.

[@MortazaHussein]

many thanks, very helpfull. Can you also make some EC3 design tutorials , such as design different types of connections? Thank you!!

[@muyomba12]

Hi mike at about 10:40 in the formula for the shear resistance you have zcotθ but when when you rearrange for S you didn’t take account of the cotθ, any reason?

[@johncliffoluoch9333]

Hello, he says if cotθ > 2.5, u limit it to 2.5z. hope that helps

[@Szhihihihihihi]

superb !

[@nickbailey1640]

Fantastic lectures Mike. Where does the Vmin formula which you use here appear in EC2, I cannot seem to find it.

[@mikebather]

Hi Nick Bailey, thanks for the question. I have not taken this formula directly from EC2 but from the Manual for the design of reinforced concrete building structures to Eurocode 2 by the IStructE. This really is just one way of doing your calcs for shear. I hope this helps, Mike

[@Okastu]

the last point was a bit confusing. Concrete itself is sufficient? I thought it wasn't and thats why we were designing those shear links in a first place. Can you please explain the last calculation?

[@mikebather]

Yes, you are right, the concrete cannot carry the applied shear forces on its own and so steel shear reinforcement is needed. Once we put the steel shear reinforcement into the concrete beam, we still need to check that the concrete is adequate - even in its reinforced state. That is what the final calculation is about. Hope that helps.

[@emillovgren]

Hi, Great tutorial, and I might be a bit late. I'm just thinking about what 5,56 is taken from in the calculation of the angle after 6 min. I can't really find out where it's taken from, if it's calculated or just a standard number. Thanks for a great tutorial else.

[@mikebather]

Hi emillovgren, thanks for the question. There are a few different ways of calculating the angle of the strut for full shear force at the end of a beam. This method comes from the Manual for the design of reinforced concrete building structures to Eurocode 2 by the IStructE. This really is just one way of doing your calcs for shear. I hope this helps, Mike

[@AkhiDeia]

Why we designing it for minimum shear force ? when we can have shear force greater than that

[@mikebather]

Hi Nial Gul Hazarboz, thanks for the question. Hopefully, I can make this a little clearer. When designing beams to the Eurocodes, you must include a minimum amount of shear reinforcement - you don't have a choice, you just have to do this. So, my approach is to check the applied shear and compare it with the shear resistance of the beam (this is the minimum shear resistance). If this minimum shear resistance is found to be OK then we are happy, if not, then we go ahead and design the shear links to suit the higher applied shear - extra work and extra rebar! Hope this helps, Mike

[@lovevideolike1010]

Sir super vedios please make more videos related SOM subject

[@RPoltavchenko]

Thank you for Your lessons, they are really great. I have a question about the equation on 5:58. It's about angle theta. This equations is from the EC2 or not? If it isnt, where i can find it. Thank You.

[@mikebather]

Hi Roman Poltavchenko, I have taken theta from the Institution of Structural Engineers book Manual for the design of concrete building structures to Eurocode 2. This is a superb design guide for practising engineers. Similar guidance can be found using the "How to" pdfs from the Concrete Centre, again in the UK and can be found at www.concretecentre.com/pdf/publicationlibrary/how2_beams.pdf I hope that this helps.

[@RPoltavchenko]

Mike Bather Thank You!!!

[@sarathcity7287]

Hi sir, I have one doubt please tell beam z length how to find

[@tungluongvan483]

why did you use z = 524mm? I saw that you used z = 0.87*d = 535 mm in "Worked example - main reinforcement".

[@mikebather]

In the main reinforcement video I use a small load and I the beam only needs minimum shear reinforcement. In order to show how to design normal shear reinforcement, I have increased the loading to the beam for this video. By increasing the loading, I also increase the bending moments in the beam and the size of the lever arm (z) reduces as the bending moment increases. I hope that this explains how I came to use different value for z in the two videos. By the way, this is a very intelligent question for a cat.

[@tungluongvan483]

thank you very much, Mike :)

[@charlescui007]

this video is really really helpful, can you upload a video about how to design RC slab please

[@mikebather]

Hopefully, this is available now.

[@giorgoskatsimpras4090]

how did you choose the legs of Reinforcement? If we assume that we had to define them..

[@mikebather]

Hi Giorgos Katsimpras, typical shear links used in the UK are 10 mm and 12 mm diameter bars. At the start of RC beam calculations you need to assume a certain diameter for the shear links. You may need to change these once you have finished the shear calculations. I guess that most designers start off with a bar size that they have used before in a similarly sized beam.

[@giorgoskatsimpras4090]

+Mike Bather . Hallo thank you very much for your respond,for your help and for your useful example. Sorry that I did not clarify before. I meant for the number of legs for the shear. How we will know if they are 2 or 4 for instance? I noticed an expression of eurocode (6.8). Once more thank you very much for your respond!

[@crazyrafi291]

I am having high torsion in the beam. So how do I consider that torsion in design?

[@mikebather]

Hi Crazy Rafi, This video is an introductory one for RC design and so does not cover more complex issues like torsion. The last beam that I designed with torsion ended up with slightly more links than those just needed for shear - but that was using the old British code of practice, not the Eurocode. I think that you would need a text book to help, Mike

[@sulaimansamatar4459]

4:10 you said minimum strength reinforcement. But the formula i believe is for strength of concrete

[@mikebather]

Hi Sulaiman Samatar, at around 4 mins in the video I am trying to compare (i) the shear strength of the beam using minimum shear reinforcement (v min) with (ii) the minimum shear force acting on the beam close to the support (V Ed). In this case V Ed is greater than v min and so I cannot rely on minimum shear reinforcement but have to go ahead and design shear reinforcement based on the shear loads on the beam. I hope that this helps clarify things, Mike

[@sulaimansamatar4459]

Mike Bather thank you for the respond. I will watch the video again

[@undhinesh]

Hi, where do i get these moment,shear and torsion formulae in euro code

[@mikebather]

Hi Dhineshkumar Rajavel, Apologies for the delayed reply. EC2 is not that user friendly for the design of RC elements and so it is best to go to a text book. In the UK Draycott and Bullman's Structural Elements Design Manual is a book that I teach with. The IStructE Manual for the design of concrete building structures to Eurocode 2 is good and the Concrete Society booklet Designed and Detailed is also good. I hope that this helps, Mike

[@undhinesh]

thankyou sir for ur kind replay i'll go through it.../

[@adam.suliman.drammen.kommune]

wonderfull thank you

[@nafis1497]

how to design if the load was point load???

[@mikebather]

The important thing to do is to carefully calculate the shear at any particular point along the length of the beam using some analysis technique or other and then the design shear force can be compared with the shear resistance of the beam. So it does not really matter too much how the loads are applied to the beam (point loads or UDL) as long as the loading is not unusually high. Hope this helps.

[@VR_SHAN]

Mike Bather whats the equation though

[@samjames2031]

my greatest of all goats