Is it necessary to use cracked section for drift check in building?

As Per ACI 318-14 Clause 6.6.3.2,

Q: Do we need to use cracked section in drift check?

A: ACI 318-14 Section 6.6.3.2 addresses the service load analysis, which would seem to include drift, although it doesn’t say that explicitly. Section 6.6.3.2.2 states that for such analyses it is permitted to use moments of inertia that are 1.4 times those defined in 6.6.3.1, which is the section that requires the use of cracked moments of inertia. The Commentary to Section 6.6.3.2.2 does refer to using this greater value in the investigation of deflections, vibrations, and building periods, so it seems reasonable to also use this greater value when investigating drifts.

P-DELTA Analysis in ETABS 2017 including respose spectrum analysis

1. Define a new load case "PDELTA".

2. Set it to start from zero condition.

3. Assign load names that will act as vertical forces when lateral sway occurs i.e usually DL + some factor*live loads.

4. Set Geometric non linearity to P-Delta

OK

Now for the load cases that you want to act once p-delta occurs set the initial conditions to "Continue from state at End of Non linear ..." where you will find the initially defined "PDELTA".

If you want to do response spectrum analysis. You need to create a new modal load case "PDMODE" and do same as above. Then in RSX and RSY load case assign modal case to PDMODE.

In concrete design do not forget to include P-DELTA in view/revise preferences.