One way and Two way slabs - When to model slab as membrane and when to model as shell thin

This structural tutorial is attending a structural doubt on one way slab and two way slab behavior. The yield line theory assumption of Ly/Lx is an approximate method for load distribution.For more accuracy,the stiffness of slab needs to be accounted by modelling a slab as a shell thin in ETABS and by modelling slabs as elements in staad pro. When to model a slab as membrane and when to model as shell thin is attended in this video
The points are summarised below
When is a slab one way
When is a RCC slab 2 way
What is yield line theory?
What is the limitation of yield line theory
Why is yieldline theory providing safe results
What are the better methods for slab analysis
#When to model slab as membrane and when to model it as shell thin.
What happend when there are only 2 supports for a slab
What you need to do when there is only 3 supports for a slab
What to do when there is a point load in a slab
How to treat cutout in a slab
How to distribute load when there is an irregular shaped slab.
The answer to most of these questions are same. You need to bring in interaction between slab and beams and let the stiffness play its role in load distribution than going by thumb rules like Ly/Lx or Long span/ short span
If you understand these basic concepts of slab and shell analysis then your structural design in software like ETABS will be more effective.
I suggest you like this video, Like our channel, Follow my channel and also follow my blog. The link is mentioned in the video.
Happy learning! Provide your comments :-)

[@Muhamadyaseen786]

Thank you sir

[@devangrathod8115]

Always worth watching your videos sir.
Full on knowlegede and your unique way of teaching makes hard things very simple to understand.

[@CIVILERABangalore]

Thanks for your words

[@PankajSingh-me4th]

Very informative loved it.

[@CIVILERABangalore]

thanks for the comment 🙂

[@nicolasmarie4398]

Hi. Thanks for the video. There are situation where we have to put the Longer Bar as B1 and the Shorter Bar as Distribution/B2 bars for example if there is a cantilever adjoined to the longer direction. I will greatly appreciate if you can talk more about this? Thanks.

[@CIVILERABangalore]

B1 need not be always short even in normal slabs. It is dependent on many things. In site it is not practical in a large building as adjacent slabs may have different orientation.
For your cantilever question, see if this video has any info th-cam.com/video/8GPx8ZIrZCM/w-d-xo.htmlsi=9LUZqg4tTEkJIciA

[@ravishankar.p5542]

Sir really your teaching is excellent 👏please I need more more videos sir....🙏🙏 Thank you so much sir.....

[@CIVILERABangalore]

Nice to see your comment Ravishankar. Nice to know you learnt from it. More videos will come but you can choose to enroll for my flagship course too if you have not 🙂

[@manuswaruprajsekar1775]

Very well explained sir. Thank u for your effort..

[@CIVILERABangalore]

:-) Nice to know you liked it

[@hcStructuralDesigns]

Yes, sir I have experienced this in cype cad.
In FEM design, one way and two way slab won't work.
Wherever the more moments we provide more steel on that direction.
Thank for the video sir.
You explained the same thing here in this video.

[@CIVILERABangalore]

but why? why 1 way and 2 way dont work? It works but only that it is approximate rule of thumb
The reality is based on stiffness which is captured in shell analysis

[@hcStructuralDesigns]

@@CIVILERABangalore yes sir.
In fem design of slab there is possibility of getting more moment in longer direction of slab.

[@CIVILERABangalore]

@@hcStructuralDesigns Thats the reality. stiffness decides the flow.

[@hcStructuralDesigns]

Sir there are two methods for detailing for slabs, one is crank bar method and another one cut piece method.
Can explain two methods in detail.
Which method is easy and economical???

[@CIVILERABangalore]

Its all covered in the courses. Is it possible to achieve detailing by cranking if the bottom rebars and top rebars are considerably diffferent? cranking works well when the slabs are small and spacings are all uniform

[@salmanlaakhani1773]

Sir, how to be add in your group ???

[@CIVILERABangalore]

If you are in my list, you would have got the invite some time. Check mails.

[@zuberibrahimsultan8771]

Which model is more accurate, membrane or thin shell ???

[@CIVILERABangalore]

shell thin will be.

[@zuberibrahimsultan8771]

@@CIVILERABangalore could you tell me why ???

[@CIVILERABangalore]

@@zuberibrahimsultan8771 Should be in the video. Membrane will replicate Yield line theory behavior and shells would do stiffness based

[@zuberibrahimsultan8771]

@@CIVILERABangalore got it. And thanks