Good afternoon,
When performing second-order analysis, does the program account for cracked section properties when computing deflections or does the user need to apply a factor of reduced moment of inertia separately for both cap and columns?
Also does the program consider long term effects for deflection? Such as deflections due to creep?
Thanks,
Danny
Danny,
If modeling cracking of section, you need to apply the reduced moment on inertia factor for the structural element under consideration. CR is applied as a strain load, and it is accounted for deflection.
I am a bit confused. Hopefully you can clarify.
Does the factor represent the cracked moment of inertia (Icr) or the effective moment of inertia (Ie)?
For example, Eq. 5.6.3.5.2-1 is used to calculate the effective moment of inertia (Ie). I'd like to know if the program is internally calculating Ie or if the "reduced moment of inertia factor" replaces Ie?
Reduced moment of inertia factor is completely under the control of the user. The program will not compute Ie. You can do a rough estimate of how much of the section will remain uncracked. That is engineering judgement. Analysis will be based on the section remaining uncracked.
Answer Verified By: Danny Villalpando