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1. ## Entering Lateral Supports and Their Effects in RF-/STEEL EC3

When designing steel columns or steel beams, it is usually necessary to carry out cross-section and stability analyses. In most cases, cross-section design can be carried out without giving further details; the stability design, however, needs additional user-defined specifications. To a certain extent, the member is cut out from the structure and therefore, the support conditions have to be specified. This is particularly important to determine the ideal critical moment for lateral torsional buckling Mcr. In addition, the correct effective lengths Lcr have to be defined. They are necessary for the internal calculation of the slenderness ratios.

3. ## Cross-Section Design of Two-Span Beam

The cross-section class of a two-span beam will be designed in the following. In addition, the necessary cross-section designs will be performed. The global stability failure will be excluded due to sufficient stabilizing measures.
4. ## Consideration of Holes in Tension Design

For the tension design according to Clause 6.2.3 EN 1993-1-1, the following formulas are given to determine the tension resistance.

$\begin{array}{l}\mathrm{Equation}\;6.6:\;{\mathrm N}_{\mathrm{pl},\mathrm{Rd}}\;=\;\frac{\mathrm A\;\cdot\;{\mathrm f}_\mathrm y}{{\mathrm\gamma}_{\mathrm M0}}\\\mathrm{Equation}\;6.7:\;{\mathrm N}_{\mathrm u,\mathrm{Rd}}\;=\;\frac{0.9\;\cdot\;{\mathrm A}_\mathrm{net}\;\cdot\;{\mathrm f}_\mathrm u}{{\mathrm\gamma}_{\mathrm M2}}\end{array}$
5. ## Pipes Under Internal Pressure Load

Pipe systems are exposed to a large number of loadings. Internal pressure is one of the most governing loads. Therefore, this article describes the stresses and deformations resulting from a pure internal pressure load in the pipe's wall and for the pipe respectively.

6. ## Lateral Torsional Buckling of a Principal Beam with I-Section According to EN 1993-1-1

This example is described in technical literature [1] as example 9.5 and in [2] as example 8.5. A lateral-torsional buckling analysis must be performed for a principal beam. This beam is a uniform structural member. Therefore, the stability analysis can be carried out according to clause 6.3.3 of DIN EN 1993-1-1. Due to the uniaxial bending, it would also be possible to perform the design by the general method according to clause 6.3.4. Additionally, the determination of the moment Mcr is validated with an idealised member model in line with the method mentioned above, using a FEM model.

7. ## Limit Values for Stability Analysis in RF-/STEEL EC3

As of the program version X.11, the filter options of small compression forces or moments for stability analysis in RF-/STEEL EC3 have been revised. The revision of these filter options in the 'Stability' tab of the 'Details' dialog box allows you to work in the module transparently since they are now independent of the design.

8. ## Structural Fire Design According to DIN EN 1993-1-2 (Thermal Material Properties)

Using RF-/STEEL EC3, you can apply nominal temperature‑time curves in RFEM or RSTAB. For this, the standard time‑temperature curve (ETK), the external fire curve and the hydrocarbon fire curve are implemented in the program. Based on these temperature curves, the add‑on module can calculate the temperature in the steel cross‑section and thus perform the fire design using the determined temperatures. This article explains the thermal behaviour of structural steel as this is a direct impact on the calculation of component temperatures in RF‑/STEEL EC3.

9. ## COM interface in VBA | 4.2 Frame Optimization

Part 4.1 of this article series described the connection of the RF‑/STEEL EC3 add‑on module and the members and load combinations to be designed were already defined. This part will focus on the optimization of cross‑sections in the module and the transfer to RFEM. The elements already explained in the previous parts are not described again.

10. ## Design and Stabilization of Beams Susceptible to Lateral-Torsional Buckling According to Eurocode 3 and AISC

A single-span beam with lateral and torsional restraint is to be designed according to the recommendations of Eurocode 3 and AISC. If the beam does not reach the required load-bearing capacity, it must be stabilized.

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