Formula 11
Do you have any questions?
![Smallest Magnification Factor for Flexural Buckling in Frame Plane](/en/webimage/010280/2993348/1_mode_shape_in_plane_buckling.png?mw=512&hash=3ae4b5e831c1025605c328fda1a888e0a3d36055)
In EN 1993-1-1, the General Method was introduced as a design format for stability analyses that can be applied to planar systems with arbitrary boundary conditions and variable structural height. The design checks can be performed for loading in the main load-bearing plane and simultaneous compression. The stability cases of lateral-torsional buckling and flexural buckling are analyzed from the main supporting plane; that is, about the weak component axis. Therefore, the issue often arises as to how to design, in this context, flexural buckling in the main load-bearing plane.
![Switch Option in Design Details](/en/webimage/010344/2992651/1_Activate_Automatic_Switch_to_General_Method.png?mw=512&hash=4deb9611952f056ff42e89ada3274387f42d24e1)
For the stability design of members and sets of members with a uniform cross-section, you can use the equivalent member method according to EN 1993-1-1, 6.3.1 to 6.3.3. However, as soon as a tapered cross-section is available, this method can no longer be used, or only used to a limited extent. The RF-/STEEL EC3 add-on module can automatically recognize these cases and switch to the general method.
![Warping Restraint via End Plate](/en/webimage/010484/2978100/1_warping_restraint_from_end_plate.png?mw=512&hash=b43e17cbb11faa3b51820d5bc88f6c5f2d58db81)
In the case of open cross-sections, the torsional load is removed mainly via secondary torsion, since the St. Venant torsional stiffness is low compared to the warping stiffness. Therefore, warping stiffeners in the cross-section are particularly interesting for the lateral-torsional buckling analysis, as they can significantly reduce the rotation. For this, end plates or welded stiffeners and sections are suitable.
![Entering Intermediate Lateral Restraint in Center of Member 1](/en/webimage/010537/2968407/1_Intermediate_lateral_restraint_in_the_middle_of_beam_1.png?mw=512&hash=b59e15e6f9f5b251a280addda3968092369a2f14)
The support conditions of a beam subjected to bending are essential for its resistance to lateral-torsional buckling. If, for example, a single-span beam is held laterally in the middle of the span, the deflection of the compressed flange can be prevented, and a two-wave eigenmode can be enforced. The critical lateral-torsional buckling moment is increased significantly by this additional measure. In the add-on modules for member design, different types of lateral supports on a member can be defined using the "Intermediate supports" input window.
![Feature 002820 | Limit Plastic Strain for Welds](/en/webimage/050344/3881226/1.png?mw=512&hash=9d7f6c198b6d4ae6ee8f2fa8bca75f85579e14c9)
In the ultimate configuration of the steel joint design, you have the option to modify the limit plastic strain for welds.
![Component "Base Plate"](/en/webimage/050345/3936120/50345.png?mw=512&hash=3bd641cb1a2445804b338855e4debfc40c6563e9)
The "Base Plate" component allows you to design base plate connections with cast-in anchors. In this case, plates, welds, anchorages, and steel-concrete interaction are analyzed.
![Feature 002807 | 3D Display of FSM Results](/en/webimage/049281/3861162/2024-05-01_10-32-55.png?mw=512&hash=2377d291bc20ac3d78d617b50c131614e99ac6f7)
In the "Edit Section" dialog box, you can display the buckling shapes of the Finite Strip Method (FSM) as a 3D graphic.
![Steel Design | Seismic Force-Resisting System Design Overview](/en/webimage/048507/3803346/seismic_steel.png?mw=512&hash=1c18a83f050e74601a7300444a0d77a0246a0e02)
- Design of five types of seismic force-resisting systems (SFRS) includes Special Moment Frame (SMF), Intermediate Moment Frame (IMF), Ordinary Moment Frame (OMF), Ordinary Concentrically Braced Frame (OCBF), and Special Concentrically Braced Frame (SCBF)
- Ductility check of the width-to thickness ratios for webs and flanges
- Calculation of the required strength and stiffness for stability bracing of beams
- Calculation of the maximum spacing for stability bracing of beams
- Calculation of the required strength at hinge locations for stability bracing of beams
- Calculation of the column required strength with the option to neglect all bending moments, shear, and torsion for overstrength limit state
- Design check of column and brace slenderness ratios