Leaderboard

Dear Baz and Ayesha, Thanks for responding and keep thread alive. ACI 318-14 Table 6.6.3.1.1 (a) dictates the stifness modifier used in the analysis. ACI 318-14 6.6.3.2.2 indicates that for service-lad analysis these modifiers can be multiplied with factor 1.4 . Column/ Wall (Uncracked) = 0.7 x 1.4 = 0.98 = 1 Ig Beams / Wall(cracked ) = 0.35 x 1.4 = 0.49 Ig The picture I am attaching below Is from a design pdf of a renowed International consultant that I usually follow. I am open for further comments in this regards.

I noticed this incorrect framing of the floor in the workshop of Azim (Suzuki) motors

I think your question has been answered above. I will only add that even for performance based design, the stiffness modifiers shall be different for each performance level. I think that is implied by the commentary. You an also have a look at the following thread to see how drift control and stability requirements are enforced by code in general design practise. It is not 100% related to your question but it gives you a nice overview of how certain elements that we talk about are incorporated into the design with us taking the fore granted. You might find it usefel.

You have added to my pool of knowledge. I had not gone through the 2014 edition of the ACI 318 code yet. The picture that you attached should concern with loadings in which pre-yield behavior is taken into the account to calculate deformations. My earlier comments were related to deformations related to design level seismic forces. Read the following excerpt form the commentary of the section 6.6.3.1.2 of 318-14. The type of lateral load analysis affects the selection of appropriate effective stiffness values. For analyses with wind loading, where it is desirable to prevent nonlinear action in the structure, effective stiffnesses representative of pre-yield behavior may be appropriate. For earthquake-induced loading, the level of nonlinear deformation depends on the intended structural performance and earthquake recurrence interval. As UBC 97, or any other building code, wants us to compare design level drift to maximum inelastic drift, one should use stiffness modifiers that reflect the yielding of the member. If one is using performance based approach, these modifiers can change. (I am talking about seismic forces)

Use the principle of superposition to calculate the combined effect of moment and axial force (P/A +- My/I).