AQUA Report - Design values of cross section

SOFiSTiK Teddy
1

Hi,
As I am quite new to Sofistik, I regulary check my results by other calculations. I have modelled a bridge beam with non-effective areas, and when checking the report from the Cross sections (AQUA), I noticed there was a difference between the table “Effective static properties of cross section” and " Design values of cross section". In spite of the fact that I find it more intuitive to use “Design values of cross section”, I have come to learn that thiese are properties for some other kind of design operations and therefore I should use the “Effective static properties of cross section”. Correct?

Quote from AQUA-manual, section 4.5:
"In case the materials have safety factors, then some analysis methods require that the stiffness
to to be reduced by the safety factors. As this would result in totally different values for
composite cross sections, an extra table for the design sectional values was introduced."

So, my question to help my understanding, is; what kind of analysis methods require the “Design values of cross section”?

Kind regards,
Øystein

2

Hello Øystein,

The non effective parts define areas that are non effective for different types of forces or moments.
This has the result that the cross section properties have to be adjusted by AQUA.

The ‘effective static properties […]’ show the actual cross section values.
The ‘Design values […]’ show the reduced cross section values.

E.g. NEFF TYPE ‘Z’:
This command deactivates the moment My for some parts of the cross section.
So AQUA reduces the Iy of the cross section, not the sectional area A or Iz.

grafik
grafik656×522 170 KB

The design values are used for further calculation (e.g. ULS with AQB).
Further information about the theoretical background of non effective areas can be found in the AQUA manual:

TEDDY > Help > manuals > all manuals > AQUA > chapter ‘3.43 NEFF - Non effective parts’

Best regards
Frederik Höller
Your SOFiSTiK Support Team