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You should not get moment from temperature load in ETABS. Because temperature is applied as axial load not as gradient like in SAP. Yes walls will fail in F11, F22 (axial force, tension mostly). But remember for tension, walls will be cracked and to account for cracking you have to apply a very low value of axial stiffness. I would say to start with F22 and F11 as 0.25 and if it still fails you can even reduce it to like 0.10 (tension will be carried only by steel) plus some portion by tensile capacity of concrete. This is true if cracks are not your concern like in water tanks etc. Imagine what is the goal of your calculations? failure mode? service or ultimate? Ultimate right? Ok, now at ultimate stage what is the predicted cracking mode? How much cracking do you expect? For axial tension, I expect fully cracked concrete with section capacity only equal to n.As. So nAs/Ag is the modifier you should use for f11 and f22 in tension. For compression, i dont expect cracks so section is mostly less cracked (only from shear or flexure).

1. I forgot to mention and as is Rummann understood correctly, that reason for using reduced stiffness for axial tension is that we will get less tension from analysis (due to less stiffness/restraint). 2. Negative temperature will produce tension near restraint (like slab supported on heavy walls). 3. What is the use of building? Is it a car park where you need to apply temperature to all the structure? Otherwise as Umar and you already pointed out, its the top slab where you need to consider differential temperature between top and bottom slab and thats not possible with ETABS 9 atleast. 4. Yes, tension should be checked on appropriate combination with other loads and that is 1.2D+1.6L+1.2T plus other loads if you have. If still you are getting tension that means it will be carried by modulus of rupture + steel only. 5. I would recommend you to use reduced stiffness of 0.25 and then also subtract the tension capacity of concrete (equal to half of 0.62(f'c^0.5)xthicknes in Mpa), half because slabs are restrained as per ACI. 6. For compression, cracking modifier should be increased but walls are quite stronger in compression. So just use 0.25. This is your separate model for temperature analysis. Keep it separate from lateral analysis where you might be using 0.7 or 0.35 modifiers for shear walls. Or it will affect the distribution of lateral forces to columns as you pointed out. But keep in mind, that is the real situation, if temperature cracks walls before earthquake hits, walls would be very weak transferring lateral forces to columns. Others can shed light on this more.

Rummaan17, Thanks for the summary. It does provide some useful background on the topic. Temperature loads should be applied but only to areas exposed to temperature differential (Roof slab or periphery members if exposed). Lets get some feedback from @Rana as he might has more experience on temperature load application in commercial design and see where this goes. Thanks.

Hi Alinalysis, Instead of labelling conditions as pinned or fixed please consider them interms of load path. Your observations reflect that for case of extremely stiff beams (Moment of Inertia of beam >> Moment Inertia of Column), relatively speaking, there would be no rotational restraint at end of beam and therefore no moment, which should be the case. Hope this answers your question. How about having super big cross-sectional columns and small cross-sectionall beam, would it affect your result? Can you guess the result without running the numbers. Thanks.