Member Type Parameters Definition (EC3)

Use this dialog to set up parameters for steel members according to the Eurocode 3 (EC3).

Access

• Click Design Steel Members Design - Options Code parameters to open the Member Type dialog, and then click .
• Click Parameters in the Definitions dialog.

This dialog is used with the following steel design codes:

• EN 1993-1:2005/A1:2014
• NF EN 1993-1-1:2005/NA:2013/A1:2014 (French Annex)

Dialog elements

Member type

Specify a name for the member type.

Buckling (Y axis) or (Z axis)

Determine the length of a member for the appropriate plane.

There are two ways to define this length:

• Select Real and specify the actual member length.

  Enter 1.0 to specify that the actual length will be adopted for each member defined using the category as Ly.

• Select Coefficient and specify a coefficient by which the real member length should be multiplied to obtain the required value. For instance, if the value 0.25 is entered, it means that the relevant length equals 1/4 of the real length. Use this method to define several members of different actual lengths simultaneously (with additional supports equally spaced) or if the parameters are to be saved as a category.

Buckling Length Coefficient

Define the member buckling length coefficients in both directions.

The actual member length (or the sum of the component member lengths) is entered automatically.

The buckling length coefficient depends on the end-support conditions of the member nodes in the buckling plane.

Click the icon corresponding to the selected buckling type, to open the Buckling Diagrams dialog which allows you to define the buckling length of a member. Once you have selected a buckling diagram, the corresponding coefficient value is automatically updated.

Buckling is always considered during calculations when a compressive force acts on a member, even if it is negligible in comparison to other internal forces. The program does not perform - on its own - a separate analysis that would determine if buckling effects can be disregarded or not.

Select in the Buckling Diagrams dialog to exclude buckling effects from the calculations.

Flexural-torsional buckling check for tees, channels and mono-symmetrical I sections

Select this option to perform an additional check of members made of specific types of shapes against flexural-torsional buckling.

Lateral Buckling Parameters

Provides options used during verification of lateral buckling for the member: lateral buckling type, load level, critical moment, and lateral buckling length coefficient.

Lateral buckling

Select this option to take into account lateral buckling during the calculations.

Click the relevant icon to open the dialog for the definition of appropriate parameters.

Load level

Determines the lateral buckling conditions.

Specify the level at which the load is applied by defining the ordinate of the load level height in the system of member section axes.

Note: Assuming that lateral buckling occurs when a load is applied to the member in the XZ plane, only one coordinate is provided. It is a relative value from the interval <-1.0,1.0>.

Lateral buckling length coefficient

Specify the appropriate section distances of a member reinforced against lateral buckling.

Two lateral buckling lengths can be fixed separately: the upper flange and the lower flange. For a compressive stress, it is possible to occur in the upper or lower flange for different load cases. Therefore, a value of the coefficient is given by which the base member length should be multiplied to obtain the lateral buckling length. The length Iz is taken as the base length. Enter the coefficient value directly or select the icon representing a typical fixing case for which the coefficient will be automatically chosen.

If you want to apply a load at a characteristic point of a section such as the upper or lower flange, click Upper flange or Lower flange, and then select the relevant coefficient to update the coordinate value automatically.

Note: According to the Belgian code (NBN EN 1993-1:2005/ANB:2010/A1:2014), calculations of cantilevers with and without warping effects differ. Therefore, the Cantilevers without warping effects option is available after you select this code. This option is active only if the Lcr = 2 lo or Intermediate bracings option is selected for the upper or lower flange in the Lateral Buckling Length Coefficient dialog. If you select other options from this dialog, the Cantilevers without warping effects option is not active.

Critical moment

Select if you want to calculate the elastic critical moment for lateral-torsional buckling automatically or manually.

If you select the User option, you need to enter a value for the specific critical moment Mcr.

Lateral buckling curve

Select a type of curve from the list (a, b, c, or d), or let the program select one automatically.

By default, Robot uses the section type and dimensions and the lateral buckling method (according to Tables 6.4 and 6.5 of the code) to select one the curves automatically.

Lateral buckling calculations method

Select the method to use for the calculation of lateral buckling.

• General method (see section 6.3.2.2 of Eurocode 2005)
• Detailed method (see section 6.3.2.3 of Eurocode 2005)
• Simplified method for beams with lateral restraints (see section 6.3.2.4 of Eurocode 2005).

Note: The Auto option is available for the Lambda, Beta and kfl parameters in the selection list for some National Application Documents. When you select this option, the program will automatically match the values of the coefficients in accordance with given NAD's recommendations. The selection list contains predefined values of the parameters; the user can enter any value of the parameter.

Note: The symbols are explained in the Results dialog (the Detailed Results tab).The dialog contains definitions of all parameters assumed in steel member calculations and result values obtained after member calculations.

Click More to open an additional dialog for definitions of the remaining member type parameters provided in the code as: load type, section parameters, etc.

Additional sets of member parameters

Select an additional set of member parameters if necessary.

• Limit deflections and displacements: select this option, and then click Service to open the additional Serviceability dialog. Member type parameters (limit displacements, camber) can then be defined
• Complex sections: select this option, and then click Complex to open the additional Complex section (Eurocode3) dialog or Complex section (CM66) dialog. The parameters of complex members can then be defined
• Thin-walled sections: select this option, and then click Thin walled button to open the Thin-walled section dialog opens. The dialog includes the definitions of parameters of the thin-walled member type used during design and verification of steel members of thin-walled sections, according to the guidelines of the EC3 EN 1993-1-3 code
• Fire analysis parameters: select this option, and then click Fire to open the additional Fire dialog where parameters of the fire resistance of a member are defined.

Click Save to add the member type of the defined name and parameters to the list of previously defined steel member types.