Deflection Plots under different loadcases

[Anonymous]

Please see the 3 attached deflection plots. 

The total deflection (Plot 1) (due to self wt, superimposed dead load and 1/3 live load) = 10mm.

However, when the loadings are considered separately the deflection due to self-weight (Plot 2) = 6mm and the deflection due to 1/3 live load (Plot 3) = 6mm; the total of these 2 alone is 12mm and greater than the value of 10mm obtained above (and this is without even considering the deflection due to superimposed dead load)?!

Please can you advise on why this may be happening.

Your urgent attention would be greatly appreciated.

[Rafal.Gaweda]

1 Keep in mind that rc deflection is not a "linear" deflection
2 Send me model to look at.

[Anonymous]

It is being modelled in Robot 2013 rather than 2014 as is shown in the linked file.

https://www.dropbox.com/s/unszlly10z0v30w/8593%20-%205th%2C%20Slab%20model%20VER%207.rtd

[Rafal.Gaweda]

You can not run only SLS design. SLS design is based on reinforcement calculated in ULS design, otherwise program has no "initial reinforcement" for further checks and it may not caclulate the best solution.

"After performing the structure analysis using FEM and calculating the required reinforcement area for the ultimate limit state, the serviceability limit state (as regards cracking calculations, stress limits, or other issues that may be considered locally) and the accidental limit state, stiffness for each finite element (FE) is evaluated in the program."

http://docs.autodesk.com/RSA/2013/ENU/filesROBOT/GUID-5825DF36-A541-4D2D-B521-A53ABB80760E.htm

My way, my results below

for 102

for 103

for 105

for SLS envelope