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Yes, you can. In that case, it will be either a Dual System if the produced lateral load resisting system is enlisted in your lateral load resisting systems table, or it may be a "Combination of two different framing systems" in the same direction. For the 1st case, your table will say whether it is permitted in your seismic zone or SDC and up to which height it is permitted, and for the other type both the framing systems shall be permitted separately in the table. For the latter case, you have to use the lowest R value and the corresponding Cd and Omega value for that lowest R. If your case is not seismic, only wind and if you want to use cross bracing to lower your structure sway, in that case there seems to be no problem. Which code r u using?

Dear Respected Engineers, ASCE7-05 states: 1. So, for the purpose of finding soil bearing pressure and comparing it with allowable soil bearing capacity (shortly for foundation sizing), are we supposed to use the above-listed combinations? 2. If the above combinations are to use for foundation sizing, then do we apply the SBC overstress of 33% when lateral loads are used with gravity loads? 3. If the above combinations are used for foundation sizing, we have to include the vertical EQ effect with the horizontal EQ effect? That's what ASCE-7 05 says, but I want to know if there is anything else. 4. What about the following combinations? I had always thought these are the only combinations to use for sizing foundations, be it shallow or deep. 5. If the above-mentioned green load combinations are permitted to use for proportioning foundation size or finding pile numbers, do we need to include the vertical EQ effect? Thanks all. Your valuable response is highly appreciated.

Dear all, Is there any program to design cold formed Purlin, or would u like to share any program or excel you use? It is very tedious to see how AISI guideline works.

I have a question though directly not related to the thread topic. that is, since the membrane takes the forces by in plane action, then shouldn't the forces transferred to the beam mostly cause the beam to undergo torsion, and maybe weak axis bending, rather than strong axis Flexure? Just a little confused.

Thanks

Okay, I understand. So it implies that Material properties may be trusted based on Fabricator's test reports but connection welds need to be inspected to verify proper strength. is it so?

Thanks SimpleStructure. What you siad is all about weldings, and pretty in depth, i appreciate it. But what about structural members plate testing? Does the Owner need to test certain amount of samples to valiadte strength of materails?

Yes, It is possible. Is the second story height higher than the adjacent story?

Assalamu alaikum, This question is more of Testing than Designing Steel structure. Say, someone is fabricating a structure as per design structural drawing. The owner wants to know how many tests need to be done for each type of member, say Rafter, Column, Bracing etc. and from where (web, flange etc.) and how many samples are in a test. Does AISC or any other relevant code prescribe Number of tests to be done to ensure Quality Control? I hope i could make my question clear. Thanks.

Thanks

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Assalamualaikum Everyone, Say i have modelled deck in etabs, and it behaves as membrane. do i need to any modifier to its properties ???? Like if its membrane, probably i am not going to apply m11,m22,m12 modifiers, but what about in plane modifiers like f11,f12,f22, as there is concrete topping, do these need to be modified ?

and it is beacuse when a section is large it attracts higher forces leading to higher reinforcement, leading to higher Mpr, leading to higher end shear at the time of hinging due to earthquake (short span is a major reason of high shear beacuse Vp=(Mpr1+Mpr2)/Ln). and this Probable shear, Vp when becomes higher than 50% of combined shear due to gravity loads and Vp, concrete Vc has to be taken 0, and required steel shear reinforcement to tackle the shear beacomes insufficient, as maybe shear reinforcement cannt be higher than 8*sqrt(f'c)bd.

It was later on found that, short beams under SMRF fail in shear when the section is large. Reducing the section iterativly to reach the optimum section, make things ok. Thanks all for your valuable comments.

Thanks for your response, Simple Structure. Can you please tell me about excluding some members from the lateral force resisting system? What changes have to be brought in analysis for not letting them contribute to lateral forces in model? Maybe its tough, i don;t know. Or, u can share the idea regarding things to do to exclude some frames from LFRS.