Optimize Cross Section - Material Safety Factor

unhandled

(Mathieu Côté) #1

Hi, I am using the OptiCroSec component to optimize the shell thickness, see attached file, and I noticed that changing the material safety factors, both gammaM0 and gammaM1, yields no change in the mass of concrete. By opposition, when using the OptiReinf component, changing the gammaMs actually changes the mass of reinforcing steel. Why is the mass of concrete not influenced by the material safety factor? The goal is to use service loads and apply a greater material safety factor to allow the selection of an appropriate shell thickness, similar to the Allowable Stress Design theory.

Thank you,

Mathieu

Karamba 1.3.2
Rhinoceros 6
Optimize Cross Section.gh (39.7 KB)


#2

Dear Mathieu,
that’s a good point! The reason for this behavior of the ‘CroSecOpti’-component is that it was initially working for beams only. The factors ‘gammaM0’ and ‘gammaM1’ refer to the design procedure for beams according to Eurocode3. Since the ‘CroSecOpti’-component will work in future for other materials than steel also, the material specific input will be moved to the ‘Material Properties’- component.
At the moment (Karamba3D 1.3.1.) one can use the ‘MaxUtil’-input to set the overall safety factor.
Best,
Clemens


(Mathieu Côté) #3

Dear Clemens,
Indeed, MaxUtil will lead to the same results.
Just to be clear, can I optimize the thickness of a concrete shell using the CroSecOpti component?
Best,
Mathieu


#4

Dear Mathieu,
you can use the CroSecOpti-component to chose the cross section height and the ‘Optimize Reinforcement’-component to determine the required amount of reinforcement.
For the CroSecOpti-component use a ‘MaxUtil’-value of around 0.5 to get economic reinforced concrete cross sections.
Best,
Clemens