Deflection Amplification for Nonstructural Components

[palves]

I am adding a new steel HSS entry portal (50' wide x 26.5' tall x 10' deep) to the front of an existing building and want to make sure the drift is within allowable limits. The problem is that I have classified my portal frame as a nonstructural component, and am now trying to figure out how to find my total ineslastic drift. It's easy with building structures and the Cd given in Ch. 12 of the ASCE7, but now I don't see how to increase my deflaction in the same way in Ch. 13. Any thoughts out there?

 

[wannabeSE]

What is the lateral force resisting system and the response modification factor, R. If it will be something similar to buildings; you can try using the R and Cd from chapter 12 to determine the drift.

 

[dhengr]

Palves:
Irrespective of how you have classified it, how does your structure know whether it is non-structural or not? And, what does this have to do with the lateral loads that it experiences? How far can it move before it starts wacking against the main bldg. How does it relate to people activity and safety? What is the definition of a structural or non-structural structure?

 

[palves]

WannabeSE : The LFRS is not a standards system, and would likely fall nearest a cantileverd column system.

dhengr : I agree that the structure doesn't know whether it's non-structural or not, but I'm using my engineering judgement to fit my structure (or non-structure) to the most appropriate analysis method so that I can apply forces to it.

You both raise good questions, but I am still curious about any deflection amplification factor when analyzing non-structural components.

 

[wannabeSE]

With cantilevered columns and inverted pendulums the Cd is equal to R. Ordinary Moment Frames will have R = Cd or R = Cd + 1/2. Without knowing more about the structural system, I would guess that using Cd = R should work.