Hi @Krzysztof_Wasik ,
I have modelled a one way simply supported slab and the results are very accurate.
Given that it is designed on the moment in the shorter direction, I am having a hard time understanding the results in 3D axis.
What is meant by Mxx and Myy? What is the difference between M1 ,M2 and Mxx , Myy?
Should M1 and M2 be interpreted via the global axis or the local axis of the panel?
After designing the slab, the area required is .26 in2/ft and it complies with the hand calculations. All the parameters are understood but what is meant by the number of bars? Since I am using #4 @ 9" c/c. this is also understandable.
1. How are number of bars for a specified diameter calculated?( It must be very easy A simple plus or minus but cant get my head around it)?
2. If I am using a concrete with compressive strength of 9ksi the only difference in moment is of -.05(decreased from 5.37 kip-ft to 5.32 kip-ft). Meaning that even using this much high concrete will still make the use of same reinforcement values. Or using this will result in lower cracks and deflection values?
Please see the images below.
