I have questions regarding MAXIMA vs AQB combinations. I am currently working on a bridge model and i am a little bit confused about difference in results.
Firstly design combination from module MAXIMA for MAX/MIN MY are 2121/2122. After i run module ULS Design, AQB creates combination 2105/2106, and generates new MAX/MIN MY comb. I know that in AQB lc 6xxx is included, but difference in results seems whey too big, also in comb. 2106 and 2105 i get the tension in wrong fibers… Can someone please explain me the difference between these two types of comb. As i saw SOFiSTiK uses 2105 and 2106 for determining reinforcement.
not a pro here. Statically determined part of prestressed is not considered in aqb comb but is in maxima comb. You should watch the video by Juergen Bellman. Is it mentioned at the end. Also you can compare normal force. https://www.youtube.com/watch?v=L_W0PCD44UQ
Ty for your answer, also video helped very much. As i understand for design SOFiSTiK uses comb 2105/2106 for main comb. But what i do not understand is why it eliminates primary part of prestress for ULS Design. It would be very helpful if someone explain that to me. Ty in advance
I would say it has something to do with 1992-1-1 5.10.1 (2). " The effects of prestressing may be considered as an action or a resistance caused by
prestrain and precurvature. The bearing capacity should be calculated accordingly. "
Ty for the answer. Still it is a little bit unclear, because if SOFiSTik disregard presence of tendons, by removing primary part of prestress, which deduct Nx and increase My bending moment, how do i know which part of bearing capacity belongs to tendons, and which part do i need to bestow to reinforcement.
Copied from aqb manual page 2-16.
Prestressing can be generally considered in two methods. Either one eliminates from the external forces and moments the statically determinate parts of the prestress and the secondary stresses, and specifies the prestressing steel with an appropriate initial strain, or one allows the action of the total internal forces and moments and observes the stress increase only. Both methods are completely equivalent. AQBS uses the first method for ultimate design, and the second method for strain checks.
Thank you very much for explanation it helped a lot. I have one more question. Do you know mby where i can find example of this method done manually? It would help a lot.
