Structural question on wall design 1

[faisal45]

Dear All,
i got from a manual that if Pu/Po < 0.35f'c x Ag then wall detailing is necessary. but if Pu/Po > 0.35f'c x Ag then wall can be detailed as column. i checked this equation in UBC Code and ACI code but did not get any information about this equation. can i follow this equation for design? can anyone know the right explanation of this equation with the reference book or code? if the equation is not right can anyone give me the right explanation when i can detail wall as column?
please explain your thoughts with the reference.(book or code)

This topic is only for RCC Building.

Thank you.

Regards
Engr. Faisal

 

[asixth]

If the compression in the wall is high then the longitudinal reinforcement needs to be restrained.

 

[samcse]

If Pu is low, you can get away with wall detailing. No rings on alternate bars etc. But if Pu is high, you must detail (at least the Compression strut) like a column.

Masroor

 

[NS4U]

I believe you will find than 0.35 in older versions of 318 (maybe pre-2005?).

That basis for the 0.35 is that in a typical concrete beam-column interaction diagram, for low axial loads (low meaning less than 0.35*Pc) that axial loads actually gives you an increase in flexural capacity. So, for low axial loads you can essentially ignore the compression load and just design the "beam-column" as just a beam.

I believe ACI did away with the 0.35 reference becuase every interaction diagram is different and the 0.35 may be unconservative in some cases.

 

[faisal45]

Dear @NS4U, i did not get any relation like Pu/Po in ACI -2002 also. can u give me the link please?

Thank you.

 

[faisal45]

D Samcse,
Under what value of Pu we can get away from wall detailing?

Thank you.

 

[hokie66]

faisal,
Your phrases "then wall detailing is necessary", "can be detailed as a column", and "can get away from wall detailing" seem to indicate that you think that details used for walls is more complex or severe than details for columns. The reverse is the case. There is no prohibition against designing and detailing a wall as a column.

 

[faisal45]

Dear Hokie,
i got my answer in your mentioned statement "There is no prohibition against designing and detailing a wall as a column".

Thank you.

Regards

 

[msquared48]

You'll just have a lot of ties...

But then, you have plenty to tie one on, wouldn't you...

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com