In the Surfaces tab of the 'Ultimate configuration' or 'Strength configuration' dialog, you can make basic settings for the design of surfaces.
The 'Design parameters' are divided into categories that differ depending on the design standard.
Utilization Limits for Ignoring Internal Forces and Stresses
This category manages one or more limit values that relate to very small stresses. If the stress is below the defined ratio η, it is not considered in the design. The background to this option is described in more detail in the chapter Members | Basis.
Construction Coefficients (for AISC)
Here, you can adjust the drag coefficient Φ (for LRFD) and the safety factor Ω (for ASD) if necessary, to be applied for the design of the surfaces.
Importance Factor of the Structure (for GB)
In this section, you can adjust the factor γ0 if necessary, by which the design values of the internal forces are multiplied. This factor is regulated in GB 50017, 3.1.9, GB 50018, 4.1.3, and GB 51022, 3.1.3. You can find further information in the standards GB 50068 and GB 50009.
Partial Safety Factor for Materials from Another Standard (for GB)
If required, you can adjust the partial safety factor for the material strength (see figure Steel Design to GB 50017): Check the 'User-defined' checkbox and enter the coefficient γR.
Options
Optionally, you can perform the plastic strain design for surfaces. This option is available for all design standards. For EN 1993, the design is performed according to the maximum allowable plastic strain, as defined for areas under tensile stresses according to EN 1993-1-5 [1] C.8(1). The recommended limit strain εpl,lim is 50 ‰.
