Notional Horizontal Loads

[ranawaseem]

Is there any NOTIONAL LOAD provision in ACI code as it is present in BS code.
The concept is to apply some %age of gravity load as horizontal load to the building and check its stability but I am not sure if this clause is present in ACI/UBC/ASCE/IBC?

 

[msquared48]

Never heard of any of that term in any of those publications.

Seems to me to be similar to a minimum sismic load though, or like a 1% minimum eccentricity on a concrete column.

What's the rationlle in the "BS" code (I assume you mean the British Standard)?

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[UcfSE]

I do not believe notional loads are included in the ACI.

 

[JAE]

In general that is correct - the ACI 318 specification primarily focuses on a magnified moment method to approximate second order effects in concrete frame structures.

However, the first paragraph of 10.10.1 (I think that is the section) does allow for a designer to use a true P-Delta type analysis as long as you include in that analysis considerations for cracking, shrinkage, etc.
ACI also adds the discouraging (and frustrating) sentence that says no matter what method you use with a second order analysis it MUST be a method that has proven to correspond to real-world behavior via testing (a hat tip to the professors out there I guess - to generate more research).

 

[asixth]

I believe that the notional load is to be considered for the global stability of the structure and for the robustness of the connections. I would not be applying the "notional 1% lateral force" to a column depending on the framing system. The column is likely there to support gravity loads and the lateral loads will be taken out by shear walls and shear cores. So I would ensure that the lateral elements have the capacity for the notional forces but not covert the column axial forces to a horizontal shear load.

Generally for building design, if the building has been designed properly for wind and earthquake forces than it will be robust enough for the 1% notional force.