Steel code check Setup dialogue - EC-EN
This chapter provides full explanation of individual parameters from the Steel Setup dialogue.
Member Check
Classification
Use Semi-Comp+
Reference
Valorisation Project: SEMI-COMP+ n° RFS2-CT-2010-00023
Description
Setting to use the plastic member capacity of Semi-Compact steel sections.
Application
When this setting is activated, modified classification limits are used for I-section and RHS sections. In addition, when those sections are classified as Class 3 the section moduli are interpolated between the elastic and plastic values in order to use the plastic capacity of the section.
Plastic analysis
Reference
EN 1993-1-1 article 5.2.2
Description
Setting to determine the plastic stress distribution of the cross-section.
Application
The result of the selected approach is used in the calculation of the α-value for the Class 1 & 2 limits.
- Elastic stresses: The elastic stresses are used to calculate the plastic stress distribution using fixed formulas.
- Yield surface intersection: A discrete plastic (yield) surface is derived for the section. The actual internal forces are then scaled until they intersect with that yield surface. The point from the yield surface that is closest to the intersection point is then used for further determination of the plastic stress distribution.
- Iterative approach: The actual forces are increased iteratively and each time the plane of deformation is calculated. In case no plane can be determined the boundary is reached. The approach then goes back one step and used the plane deformation of that step.
Shear
Use Ay, Az instead of elastic shear
Reference
EN 1993-1-1 article 6.2.6(2),(4)
Description
Setting to use the plastic shear check instead of the elastic shear check.
Application
In case a cross-section has no formula defined for the shear area the elastic shear check is executed instead of the plastic one.
When this setting is activated, the plastic shear check is executed instead, using the Ay and Az shear areas defined in the cross-section.
Torsion
Limit for torsion
Reference
EN 1993-1-1 article 6.2.7
Description
Limit value to ignore torsion in combined checks.
Application
In case a member is subject to torsion, but the torsion check remains smaller than the limit set in this field, the torsion is considered as insignificant and is ignored in the combined checks.
Default sway types
y-y
Reference
EN 1993-1-1 article 6.3.1.3
Description
Setting for the sway type y-y.
Application
The sway type is used for determining the appropriate buckling coefficient ky.
z-z
Reference
EN 1993-1-1 article 6.3.1.3
Description
Setting for the sway type z-z.
Application
The sway type is used for determining the appropriate buckling coefficient kz.
Buckling length ratios ky, kz
Max. k ratio
Reference
EN 1993-1-1 article 6.3.1.3
Description
Limit for the buckling ratios for flexural buckling.
Application
Value which serves as a limit for the calculated buckling ratios. The buckling ratios are 'capped' at this value.
Max. slenderness
Reference
EN 1993-1-1 article 6.3.1.3
Description
Limit for the slenderness for flexural buckling.
Application
In case the slenderness for flexural buckling (around either axis) exceeds this limit a warning is shown on the output.
2nd order buckling ratios
Reference
EN 1993-1-1 article 5.2.2(7)b
Description
Setting for buckling ratios in case of 2nd order analysis.
Application
In case of 2nd order analysis this setting is used to determine the buckling ratios:
- According to input: the buckling ratios are the same as for a linear analysis
- All non-sway: Calculated buckling ratios are recalculated using the non-sway setting
- l = L: The buckling length equals the system length
Lateral torsional buckling curves
Lateral torsional buckling curves
Reference
EN 1993-1-1 article 6.3.2.2, 6.3.2.3
Description
Setting for selecting the lateral torsional buckling curves.
Application
Used in the determination of the reduction factor for lateral torsional buckling.
Method for C1, C2, C3
Reference
EN 1993-1-1 article 6.3.2.2 (2)
Description
Setting for selecting the calculation method of the C1 C2 C3 coefficients.
Application
Used in the determination of Mcr, the elastic critical moment for lateral torsional buckling.
- ENV 1993-1-1 Annex F: A tabulated method where the actual moment diagram is compared to standard diagrams.
- ECCS 119/Galea: A graphical method which accounts for interaction between transverse loading and end moments.
- Lopez, Yong, Serna: A closed-form formula for C1 which accounts for the actual moment diagram.
Method for kc
Reference
EN 1993-1-1 article 6.3.2.3 (2)
Description
Setting for selecting the calculation method of the kc correction factor.
Application
Used in the determination of the modified reduction factor for lateral torsional buckling. The kc factor can either be determined from Table 6.6 or derived from C1 which gives a more exact value.
General settings
Elastic verification
Reference
EN 1993-1-1 article 6.2.1 (5)
Description
Setting for performing the Elastic verification.
Application
When this setting is activated, the Elastic verification is performed always, even for sections which could normally be checked using plastic resistances.
Verify only section checks
Reference
EN 1993-1-1 article 5.2.2 (7)a
Description
Setting for only verifying the section checks.
Application
When this setting is activated, no individual stability checks for members are executed. This setting is typically used in case 2nd order effects and imperfections are fully accounted for in the global analysis.
Flexural buckling accounted for by 2nd order calculation
Reference
EN 1993-1-1 article 5.2.2 (7)b
Description
Setting for neglecting flexural buckling checks.
Application
When this setting is activated, flexural buckling is neglected. This setting is typically used in case 2nd order effects and imperfections for flexural buckling are accounted for in the global analysis but torsional and lateral torsional buckling still have to be verified.
Moments on columns in simple construction
Reference
Access-Steel SN005a-EN-EU, SCI Publication P365
Description
Setting to account for moments on columns in simple (pinned floor beam) construction.
Application
When this setting is activated, additional moments are determined within the columns at the position where pinned floor beams are connected. The additional moments are caused by the eccentricity of the pinned connection with respect to the centerline of the column.
Fire resistance
Requirement
Required fire resistance
Reference
EN 1991-1-2 article 2.5
Description
Time during which the member should maintain its load bearing function when exposed to fire.
Application
Used in the final verification of the fire resistance.
Net heat flux
Emissivity related to the fire compartment εf
Reference
EN 1991-1-2 article 3.1(6)
Description
Emissivity related to the fire compartment.
Application
Used in the calculation of the net radiative heat flux component.
Emissivity related to the surface material εm
Reference
EN 1991-1-2 article 3.1(6) and EN 1993-1-2 article 2.2(2)
Description
Emissivity related to the surface material.
Application
Used in the calculation of the net radiative heat flux component.
Configuration factor φ for radiative heat flux
Reference
EN 1991-1-2 article 3.1(6) and (7)
Description
Configuration factor for the radiative heat flux.
Application
Used in the calculation of the net radiative heat flux component.
Temperature-time curve
Temperature-time curve
Reference
EN 1991-1-2 article 3.2
Description
Setting to select the nominal temperature-time curve.
Application
Used for determining the gas temperature at a given time.
Coefficient of heat transfer by convection αc
Reference
EN 1991-1-2 article 3.1(3)
Description
Coefficient of heat transfer by convection.
Application
Used in the calculation of the net convective heat flux component.
Structural fire design
Analysis type
Reference
EN 1991-1-2 article 2.5(2) and EN 1993-1-2 article 4.2.1
Description
Analysis type for the verification of the fire resistance.
Application
The verification of the fire resistance can be executed in the resistance domain, the time domain or the temperature domain.
Use adaptation factor for shadow effect ksh
Reference
EN 1993-1-2 article 4.2.5.1
Description
Setting for taking into account the shadow effect adaptation factor.
Application
Used in the steel temperature development of unprotected internal steelwork.
Cold formed
Local and distorsional buckling
Use manufacturer provided effective section properties
Reference
EN 1993-1-3 article 5.5
Description
Setting to use manufacturer provided effective section properties.
Application
When this setting is activated, effective section properties from the manufacturer are taken from the Effective Section Library instead of calculated by the EN 1993-1-3 calculation methods.
Stiffener iteration
Reference
EN 1993-1-3 article 5.5.3.2(10) and 5.5.3.3(9))
Description
Setting to calculate the stiffeners iteratively during the effective section calculation.
Application
When this setting is activated, an iterative process is used to calculate the effective section of plane elements with edge and/or intermediate stiffeners.
This setting cannot be used in conjunction with the 'Use lambda,p,red' setting of 'Plated structural elements' due to the fact that the stiffener iterations require the use of fyb.
Overall cross-section iteration
Reference
EN 1993-1-3 article 5.2.2(3)
Description
Setting to use iterations over the total cross-section during the effective section calculation.
Application
When this setting is activated, the effective section calculation over the total cross-section is done in an iterative way which uses the effective section of the previous step as starting point for the next iteration.
This setting can only be activated in case also the 'Stiffener iterations' setting is activated.
Local transverse forces
Ignore check
Reference
EN 1993-1-3 article 6.1.7.1(3)
Description
Setting to ignore the Local Transverse Forces check.
Application
When this setting is activated, the Local Transverse Forces check is ignored in the entire project. The check can for example be ignored in case the local load or support reaction is applied through a cleat that is arranged to prevent distortion of the web.
Bearing length Ss
Reference
EN 1993-1-3 article 6.1.7.2
Description
Default value for the nominal length of stiff bearing Ss.
Application
Used in the determination of the Local Transverse Forces resistance as the length over which the local load or support reaction is spread.
Use Ia correction in (6.18)
Reference
Corrections and amendments to EN 1993-1-3, 2010.
Description
Setting to account for a correction of la, the effective bearing length for the relevant category.
Application
Following this reference, using la = 10 mm for the end support reaction force (category 1) results in a very conservative resistance. A modification is given for case 2 and 3 of Figure 6.9: la = c + Ss.
Combined bending and axial compression
Interaction
Reference
EN 1993-1-3 article 6.2.5
Description
Setting to select the interaction method for combined bending and axial compression.
Application
Using this setting either the standard interaction of EN 1993-1-1 article 6.3.3 can be selected or the alternative given in EN 1993-1-3 article 6.2.5(2).
Buckling resistance of the free flange
Limit for large axial force
Reference
EN 1993-1-3 article 10.1.4.2(5)
Description
Limit value to distinguish between a large and small axial force.
Application
Within this article the code specifies a method for the buckling length of the free flange in case of a 'relatively large axial force'. The axial force is considered as 'relatively large' in case the unity check for normal force only exceeds the limit set in this field.
Plated structural elements
Use λp,red
Reference
EN 1993-1-5 article 4.4(4)
Description
Setting to use the reduced relative plate slenderness.
Application
Using this setting the relative plate slenderness is reduced using the ratio between the maximal design compressive stress in the element and the yield strength.
Note
This setting cannot be used in conjunction with the 'Stiffener iterations' setting of 'Cold Formed' due to the fact that the stiffener iterations require the use of fyb.
Use Annex E
Reference
EN 1993-1-5 Annex E article E.1(1)
Description
Setting to use the alternative method for determining the effective section as given in Annex E.
Application
Using this setting the alternative method for determining the effective section at stress levels lower than the yield strength is applied.
Buckling defaults
See Relative deformation parameters
Relative deformation
See Relative deformation parameters
Autodesign
Consider arbitrary members as prismatic for Autodesign
Description
Setting to consider arbitrary members as prismatic during Autodesign.
Application
When this setting is activated, arbitrary members are considered as prismatic, leading to a faster but less accurate Autodesign.