When Eurocode 3 standard is the steel standard selected for the current project, the Calculation Settings dialog box allows the definition of the steel calculation settings.
Main menu: select Settings > Steel Design > Design Settings.
Ribbon > Analysis tab > Steel Design panel > Settings.
Eurocode 3 Calculation Settings - Verification
This tab allows the selection of the shapes calculation type and enables / disables the steel verifications.
Cross sections strength: Enables / disables the Cross sections strength verification during the shapes calculation.
Elements stability: Enables / disables the Elements stability verification during the shapes calculation.
fire verification: Enables / disables the Fire verification during the shapes calculation.
Time: Defines the fire exposure period. The fire verification is done according to §4.2 (simplified method) of EN1993-1-2.
Calculation type: Allows the selection of the shapes calculation type, considering the force type taken into account:
tension - compression: only Fx
combined bending: Fx, Fz and My
oblique bending: Fx, Fy, Fz, My and Mz
Global sway imperfections: Check the option to take into account the global sway imperfections as described in article 5.3.2 from EN1993-1-1.
Local bow imperfections: If checked, the user can specify, besides the global imperfection parameters, the direction on which the local bow imperfections are considered (local y or z).
Crown imperfection (EN13031-1): Check this option to take into account the crown imperfection as described in EN13031-1.
2nd order analysis (for static comb only): perform analyses for global sway imperfections (+ local bow imperfections) + non-linear analysis. (see Local bow imperfections).
In compliance with Eurocode 3, imperfection generation involves the creation of additional load cases that introduce forces from imperfections. These new cases are derived from the existing load combinations. However, to prevent the generation of imperfections for all existing combinations, Advance Design includes a feature that allows you to select only the combinations where imperfection forces are highest.
You have two options:
Columns bucking lgth = element lght: consider the column buckling length equal to the element length.
Columns buckling lgth = properties list: when disabled, the buckling length calculation will not be performed.
Columns bucking neglected: neglect the column buckling lengths.
Beams bucking lgth = element lght: consider the beam buckling length equal to the element length.
Beams buckling lgth = properties list: when disabled, the buckling length calculation will not be performed.
Beams bucking neglected: neglect the beam buckling lengths.
Within this tab, you have the ability to set and customize the safety factors for your project. By configuring these settings, you can tailor the safety factors to meet the specific requirements and constraints of your project.
Calculation Settings - Safety factors
With the Partial safety factors tab you can establish custom safety factors for Steel Design.
By default, the system selects Auto, which means that it uses values from national annexes or EC3.
Significance of factors:
γM0 partial factor for resistance of cross-sections whatever the class is
γM1 partial factor for resistance of members to instability assessed by member checks
γM2 partial factor for resistance of cross-sections in tension to fracture
Note: The imposed factors will be applied when generating load combinations. The partial safety factors must be set before generating the combinations. If combinations are already generated, after setting values for partial safety factors, the combinations must be regenerated.
This tab defines the shapes optimization settings.
Calculation Settings - Optimisation
Optimisation mode
Allows the selection of the optimization method. The shapes optimization is created function of the selected criterion:
by element: When an element is under or over sized, the steel expert proposes to replace the first and the last cross section with more suitable shapes.
by sections: The operation described here is applied to all the elements with the same cross sections. The elements with variable inertia are ignored.
by design template: The operation described here is applied to all the elements defined by the same design template.
by name: The operation described here is applied to all the elements with the same name.
per system: The operation described here is applied to all the elements from the same system.
Find new sections
Defines the work ratio limits taken into account for the cross sections optimization. The steel elements work ratio can be defined by one limit or by both (superior and inferior limit):
If the work ratio obtained on a shape exceeds the limit imposed by the user (by default 100%), the steel expert proposes a more resistant shape.
If the work ratio is inferior to the limit imposed by the user (by default 50%), the steel expert proposes a weaker cross section for which the work ratio is inferior to the imposed limit.
If the maximum/all deflection ratio exceeds the limit imposed by the user (by default 100%), the steel expert proposes a more adequate solution.
Search range
Define the search range for new section (automatic or automatic with a maximum limit).
Apply new section to the whole super element: if enabled, during the steel section optimization, when the user accepts a new section for an element that is part of super element, the other elements are updated as well.
This tab defines the sorting criteria used for determining the most stressed cross sections.
Calculation Settings - Sort profiles
Sort Mode
Deflection work ratio: The most stressed element is the one with the highest 1/L ratio. This option is available for the chained optimization.
Strength/stability work ratio: The most stresses element is the one with the highest work ratio.
Envelope criterion: The most stresses element is the one with the highest 1/L ratio or with the highest work ratio (resistance or stability). This option is available for the chained optimization.
Note
To enable the Chained optimization, select the corresponding option in the Calculation Sequence tab of the Steel Design Calculation Settings dialog box.
Search type
Select the search criteria - by heigth, by width, by ly inertia, by lz inertia, by weight (only one option can be selected).
Limits for profiles
Select the maximum/minimum height and width for profiles.
This tab defines the buckling lengths calculation method.
Calculation Settings - Buckling
Method selection
Defines the buckling lengths calculation method:
ρA ρB
η1 η2 (specific to EC3 ENV)
Detect intersections along a super element for automatic buckling lengths: If it is not activated, then the auto calculation is performed considering the super element as a single member, no matter the intermediate intersections with the other members. If it is activated, then it calculates the buckling lengths separately for each segment/element of superelement, considering the intermediate intersections.
Note
The settings made in this tab do not affect the elements whose properties are defined by design templates; in this case, the element design properties are linked to the corresponding template.
Calculation Settings - Angle verification
In this tab you can set the bolt parameters for the calculation of the net area of sections (Longitudinal and transversal edge distance, bolt spacing and partial safety factor).
This tab defines the verifications to perform during the steel calculation.
Calculation sequence
Verify: Verifies if there are steel elements errors.
Calculate buckling: Performs the buckling calculation considering the settings made in the Buckling tab of this dialog box.
Verify deflections: Performs the automatic verification of deflections.
Calculate shapes: Performs the calculation of steel shapes according to the settings made in the Verification tab of this dialog box.
Chained optimisation: Using this command you can define an iterative calculation of steel elements, connecting all the operations selected above in successive iterations. The process iterates until all shapes are optimised as to correspond to the work ratio defined in the Optimisation tab of this dialog box. The iterations stop also when no optimisation solution is found for certain elements, or when it has reached the maximum imposed number (defined in the Optimisation tab).
Number of complete calculations: when the Chained optimisation option is enabled, you can input the number of iterations for the calculation of steel elements.