Change in Design Axial Force..?

[fatikaya]

hi, I've found that the design axial force normally increases as you move to the lower floors, while it usually makes a jump when it comes to the basement. I guess this is due to the combination chosen by the program. Does the fact that we accept the basement as a rigid floor have an effect on the program choosing the combination like this? Or what is the reason for this?

good luck..

 

[siromar]

The main factor in the selection of the combination is the capacity diagram. If the unfavorable situation is in the tensile region, the moment carrying capacity will increase as the axial load increases, and in the compression region, the moment carrying capacity will decrease as the axial load increases. The reason why the 0.5*A*fyk condition is sought is the desire to stay on the side of the tensile zone sought in the column. The axial load corresponding to the most unfavorable combination according to the capacity diagram will also be shown in the report. If you look at the axial loads of any column for the same combination from the column-reinforced concrete tab, you will see that there is no such jump. Choosing the basement as a rigid floor has an effect on the earthquake load calculation. Otherwise, it should have no effect on the 1.4g+1.6q combination. (Of course, the situation is different in the columns corresponding to the outer curtains)

 

[fatikaya]

thanks for the information you provided. Good luck with.