7/24/2019 Dezactivarea Optiunii de Limitare a Zveltetii

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Scia Engineer

Check if < lim

This values for and lim, and the corresponding check, can be found in the Concrete menu > Concrete slenderness.

If >lim, 2nd

order effects have to be taken into account.

Option Buckling data

In the Conrete menu > Setup > General: Calculation > Tab columns, the option Buckling data can be found. By default thisoption is activated.

It is important to know that:- When this option is not activated, only the 1

storder bending moments are taken into account.

- When this option is activated, also the moments caused by geometrical imperfections and the nominal 2nd

order moments aretaken into account. This means the eccentricities eiand e2have to be calculated supplementarily, and in this way the problem ofbuckling is also taken care of (e2 depends of the buckling length l0):

e1= Md/Nd

(Where Md, Ndare the values from 1st order calculation.)

Note that if no second order moment is required according to art 5.8.3.1, only the moment caused by geometrical imperfectionsis taken into account and not the second order moment.

Effective length

The effective length (=buckling length) is calculated by default by Scia Engineer. Attention: this is only valid for simple structures!

In Concrete menu > Setup > Design defaults, can be found that for buckling around the local y axis (Y-Y) nd for for bucklingaround the local z axis (Z-Z), the structure is by default considered as sway:

Off course, the user can assign specific buckling data to each member separately. To do so, select a member and click in theProperties menu on the [...] button behind Buckling and relative lengths. Here you can choose to input your own buckling factor(beta) or length (l).

The effective length based on these buckling data is required to calculate e2 and the corresponding moment M2.

Recalculated internal forces

In the Concrete menu > Internal forces, the following results can be asked for:

- The values for Mx, My, Mz, which are the 1storder design moments.

- The values for Mx,recalc , My,recalc , Mz,recalc , which are the recalculated design moments where the moments caused bygeometrical imperfections and the nominal 2

ndorder moments are taken into account. (MEd = M0Ed+ M2)

Reinfor cement design

In the Concrete menu > Member design - Design, the values for As,req are calculated based on the recalculated design valuesof the internal forces (My,recalc and Mz,recalc).