Shamim Ahmmed

9 minutes ago, BAZ said:

It is not only the difference of moments, the difference of axial load is also responsible for increased demand. The lower axial load, coupled with increased moments is the reason.

In top story, the unbalanced moment is distributed among three members. In lower stories, four members share the unbalanced moment at the beam-column joint.

It's helpful answer.

According to your comment in concrete frame structure, column unbalanced moments  will be always greater than it's immediate lower story column moment?

because top story will always three members.

Thank you Sir @BAZ

I got the point, why Longitudinal reinforcement increasing, Due to M2-2 & M-33 is greater in Upper story than Lower.
But another question arrived in my mind why upper story M2-2 @ M3-3 is larger than bottom? File Attached.
though I assigned less load in Upper story than Bottom story beam and slab.
No Wind & earthquake load applied.
Please Explain me.

Sir @BAZ

I can't understand.

Please explain me elaborately.
should i assign fix support in base??
Please tell me. 
 

Assalamualaikum to all.
I analyzed a two story residential concrete building in ETABS 9.7

After designing the structure ETABS shows more Longitudinal Reinforcement in upper story.

is it right??

In my concept, bottom story longitudinal reinforcement should be large. 
I modeled the structure as pin support at base and there is no seismic and wind load applied.

Column axial load and longitudinal reinforcement snap shoot are attached below.

Help me Please.
Thanks in advance.
 

Thanks Ayesha,
I want to know why i need to active Ux, Uy, Uz, Rx, & Rz. Why not Ry for 2D Frame analysis in XZ plane?
above this condition @waqar saleem solved my problem.
I also want to know which degree of freedom should i keep active for 2D Frame analysis in YZ plane.

Assalamualaikum to all

I analysed a two story  concrete Building in ETABS.
After analysis the positive bending moment is +15.80 kip-ft and Negative B.M is -19.99 kip-ft

when i design the building frame, ETABS calculate less positive B.M +9.99 kip-ft and negative B.M is  -19.99 kip-ft
I can't understand why ETABS calculate less positive bending moment in designing?
Please help me.
Thanks in advance.

Screenshot are given here.
 

Thank you brother.
i have got it.
But i don't know the meaning of Building Degree of freedom.

what does it mean Ux,Uy,Uz.
why i use( tick) click on every box except Ry in continuous beam analysis?
thanks in advance
excepting an analytical reply brother. 

Here my $ET file.
Please check it Brother.

Continuous Beam.$ET

here my EDB file

Continuous Beam.EDB

Assalamualikum,
I have analyzed a Beam Column Frame.
All beam(9"x 24") and column(12"12) are in section.
All columns are 20' spaced from each other.
I imposed Super Dead Load 2.15 k/lf
Live Load 2.65 k/lf
In Moment 3-3,
For typical load combination ( like 1.2 DL+1.6 LL)
why positive bending moment changes due to its story height (marked in red circle) though all story beams are equally loaded.
Can anyone tell me the reason?
 Thanks in advance.

Thanks
I want a link where i can download ETABS 2016.
can you help me please?

Thanks brother.
what should be the minimum depth(D) of foundation??

Thank you so much brother.
what is the meaning of Longitudinal reinforcement 4.2 or whatever a Numeric value?

Longitudinal Reinforcement= Rebar parentage x section of column
is it??????

Salam to all,
Is there any rules to depth of foundation(Df)
Say, I need MAT foundation on SBC=1.43 ksf.
what would be the depth of Mat Foundation (Df) from Existing Ground Level.

Assalamualikum,

what is the meaning of Longitudinal Reinforcement,Reinforcement percentage in ETABS output.
Say, a column reinforcement percentage is 2.3%
what is the meaning of it?
again,
say, longitudinal reinforcement is 4.2
what is the meaning of it?
Why do i need to know this parameter?