Transformed Area Method for Cracked Elastic RC Section (2/2) - Reinforced Concrete

Overview of analyzing RC beam sections that are in-service or the sections are cracked and the materials are still in the linear elastic range. The video discusses the use of the transformed area method and compares the use of section equilibrium to locate the neutral axis depth.

[@atifsaeed1692]

Simply, you are awesome...Great Lectures

[@minutillo67]

Excellent video!

[@RupertandTurtle]

Dude! Your videos are amazing, you explain so well and you know your shit! Thanks for all the help and wish you the best

[@yerdauletabuov7922]

Thanks structurefree team!

[@randaabonaja5057]

I was kind of wondering where did you studied your major (structural engineering) because your explanation helped me understand the whole core instead of suffering in class in my university (American University of Beirut).
Thank you for the videos.
Amazing Explanation !!

[@darthkareem111]

Randa Abo Naja no way hahah. AUB student here trying to make sense of cive413 before our first exam 😄

[@Jinyo065]

thanks alot! more power

[@michelepadula8410]

Your video is great, but i have a question: how can we state that "Cna" (depth of neutral axis) coincides with the depth of the section centroid? It would seem something like an approximation, but how could we deal with the case in which the latter is not admissible? Thanks in advance!

[@alsubaihawiful]

I have a question:
When do we use (n-1)As, and nAs? and why?

[@alzahraniabdulrahman]

you use (n-1)As in case of uncracked section. and nAs for the cracked section. I know it is 4 years question. :) but maybe someone else has the same question. good luck

[@ibrahimkaweema4746]

Thanks .

[@pranjibpaul5482]

this is very helpful.can you please tell me how can i calculate "I" (moment of inertia) from this section?

[@atifsaeed1692]

Sir, the question (n-1)As and nAs difference is still unknown to me. Can you please answer the question below my comment, by A Alsubaihawi.

[@snowneedle]

Can we take our reference anywhere else or should it be at the top? e.g if we want to use the N.A as our reference to calculate for Cna. Can we take our moment of area about existing N.A?

[@structurefree]

+snowneedle Yes, you can take the reference anywhere. Usually the top, bottom, or the neutral axis itself are the most convenient choices.

[@SG-rg5hz]

Sir, due to crack in concrete , Neutral axis doesn't change it's position. Right?

[@structurefree]

the neutral axis is different before cracking and after cracking.

[@SG-rg5hz]

@@structurefree So, the neutral axis will shift upward. Right sir???

[@impohatsantiago3744]

Shouldn't the transformed area be (n-1)*As?
Once you transform the area to n*As, you should subtract the As of the bars, or else you would be adding that area twice in the n*As centroid.
I just did an exercise given on my university, and avoiding this gave me a significant error, and not in equilibrium.

[@structurefree]

That would be true if the section was not cracked in tension.

[@civilideas1925]

👍🏻

[@khumbelobele6674]

Your video is helpful but for some who's clueless like me is not making sense.

[@structurefree]

khumbelo bele i would start over from basic beam bending before getting into composite beams.

[@khumbelobele6674]

Thank you very much.