The API for RFEM 6, RSTAB 9, and RSECTION is based on the WebService concept. To get a good introduction to the subject, the following article will explain a further example in C#.
In RF-/FOUNDATION Pro, the foundation design requires the definition of the corresponding loading (load cases, load combinations, or result combinations) for different design situations (STR, GEO, UPL, or EQU).
A member's boundary conditions decisively influence the elastic critical moment for lateral-torsional buckling Mcr. The program uses a planar model with four degrees of freedom for its determination. The corresponding coefficients kz and kw can be defined individually for standard-compliant cross-sections. This allows you to describe the degrees of freedom available at both member ends due to the support conditions.
In RFEM and RSTAB, you can check the plausibility of entries before you start the calculation. This is done using "Tools" → "Check Plausibility ..." or the corresponding button in the toolbar. There are three different types of checks available.
The German Annex to EN 1992‑1‑1, the National Addition NCI to Article 9.2.1.2 (2), recommends to dispose the tension reinforcement in the flange plate of T‑beam cross‑sections on a maximum of one width corresponding to the half of a computed effective flange width beff,i according to Expression (5,7a).
In RF-/STEEL EC3, you can optimize a cross-section automatically within the design. To do this, select the corresponding cross-section in Table 1.3 or define variable parameters for a welded cross-section.
In RFEM, surfaces are automatically connected if they have common boundary lines. If the definition line of a surface is lying in another surface, the line is automatically integrated into the surface, provided that it is a planar surface. For quadrangle surfaces, however, automatic object detection would be relatively time-consuming. For this reason, the corresponding function is deactivated. The integrated objects must be specified manually.
For a clearer display of the structure, you can display it in different colors. The corresponding selection can be opened by right-clicking the work window.
In the course of a reasonable pre-dimensioning of cross-sections, you can optimize the cross-sections of the corresponding section series in the RF‑/TIMBER Pro add-on module.
The final results of the designs of members and sets of members in the RF‑/STEEL EC3 add-on module can be displayed graphically in the work window of RFEM and RSTAB. By selecting the corresponding design case in the load case menu, the results contained in it are displayed.
The averaged internal forces from the previously defined average regions can also be used for designing concrete surfaces. To do this, click [Details] in RF‑CONCRETE Surfaces, then select the corresponding check box. This function is accessible only if you previously defined an average region.
Describing the procedure for the serviceability limit state design of a floor slab made of steel fiber reinforced concrete. This article shows how to perform the corresponding design for the SLS by means of the iteratively determined FEA results.
RFEM offers the following options to design a pinned end plate connection. First, there is the option in RF-JOINTS Steel - Pinned to enter the corresponding parameters quickly and easily to receive a documented analysis, including graphics. It is also possible to model such a connection individually in RFEM and then to evaluate or manually design the results. In the following example, the particularities of this modeling will be explained and the shear forces of the bolts will be compared to the corresponding results from RF-JOINTS Steel - Pinned.
In RFEM, structures can be modeled and analyzed in a spatial environment. The permanent 3D visualization helps you to better understand complex models and to represent the force flux. However, you can switch from a spatial mode to a planar sheet mode in the documentation of a calculation. To do this, you have to describe the spatial calculation of the structure with all the necessary properties on "flat" paper pages for an independent reader. Usually, you try to display the load actions and the corresponding results by using an orthogonal view of the substructure of the entire structure. Obviously, the load symbols depicted in the 3D mode in a view perpendicular to the load become unrecognizable due the missing expansion. In order to be still able to create a clear representation of all information, the corresponding adjustments are available in RFEM.
Loading panes of insulating glass due to climatic effects are clearly regulated in DIN 18008. In the case of the corresponding pane geometry, this load type can also govern for the ultimate limit state design. The FE design on the entire structure with the space between panes represented as the volume of a gas provides exact results for the analysis. However, a plausibility check is also becoming increasingly important. This article shows various options for performing these checks.
According to Clause 7.3.2 (2), standard DIN EN 1992-1-1 requires: "In profiled cross‑sections like T‑beams and box girders, the minimum reinforcement should be determined for the individual parts of the section (webs, flanges)." In the case of a floor beam with a T‑section, the minimum reinforcement should be determined for both flanges and the web if the corresponding partial cross‑sections are in the tension area. Image 01 shows the division into partial cross-sections.
Critical load factors and the corresponding mode shapes of any structure can be determined efficiently in RFEM and RSTAB, using the RF-STABILITY or RSBUCK add-on module (linear eigenvalue solver or nonlinear analysis).
With program version RFEM 5.06, you can edit several tendons in the RF‑TENDON add‑on module simultaneously. To do this, it is necessary to select the corresponding tendons in the tendon arrangement table.
In RF-/DYNAM Pro – Equivalent Loads, a signed result option in accordance with the dominant eigenmode has been available since version X.06.3039. For the modal combination of results corresponding to the single eigenvalues, a quadratic combination rule has to be used. In RFEM and RSTAB, the SRSS and the CQC rule are available. Only results, not loads, are allowed to be combined directly. The reason is the mode shapes, which are arbitrarily scaled and signed.
As in RFEM, load combinations can be generated automatically in RF‑PIPING. This feature is activated by default and creates the recommended load and result combinations for piping design. It is necessary to assign the relevant action category to load cases in order to generate the correct combinations. To do this, new action categories have been implemented specifically for loads on piping. Pressure temperature conditions are generated as the sets of the first (second, third, and so on) load case of the "Pressure" category and the first (second, third, and so on) load case of the "Temperature" category. The default setting can be reviewed or adjusted in the "Grouping of Thermal and Internal Pressure Load Cases for Operating Combinations" dialog box. You can access this dialog box by clicking the corresponding button in the "Piping Load Combinations" tab of the "Load Cases and Combinations" dialog box. This dialog box is automatically offered to check your entries in the case of any change of the load case from the "Pressure" or "Temperature" category.
The network-capable Project Manager controls the projects of all Dlubal Software applications in one central location. A table displays the important information for each model and corresponding file. Now, you can set dimension and weight units in the program options.
Due to the structural efficiency and economic benefits, dome-shaped roofs are frequently used for storehouses or stadiums. Even if the dome has the corresponding geometrical shape, it is not easy to estimate wind loads due to the Reynolds number effect. The external pressure coefficients (cpe) depend on the Reynolds numbers and on the slenderness of the structure. EN 1991‑1‑4 [1] can help you to estimate the wind loads on a dome. Based on this, the following article explains how to define a wind load in RFEM. Wind loads of the structure shown in Image 01 can be divided as follows: Wind Load on Wall, Wind Load on Dome.
The RF-FORM-FINDING add-on module determines equilibrium shapes of membrane and cable elements in RFEM. In this calculation process, the program searches for such geometric position where the surface stress/prestress of membranes and cables is in equilibrium with natural and geometric boundary conditions. This process is called form-finding (hereinafter referred to as FF). The FF calculation can be activated in RFEM globally in the "General Data" of a model, "Options" tab. After selecting the corresponding option, a new load case or a calculation process called RF-FORM-FINDING is created in RFEM. An additional FF parameter is available for defining surface stress and prestress when entering cables and membranes. By activating the FF option, the program always starts the form-finding process before the pure structural calculation of internal forces, deformation, eigenvalues, etc., and generates a corresponding prestressed model for further analysis.
The first part of the post about the COM interface describes opening and closing RFEM. VBA programming language is used in Excel; however, the program sequence is the same as for programming with C#. First, it is necessary to add the corresponding reference in VBA to recognize the commands for the interface. The image on the left shows an example of RFEM 5.
In addition to the general information about the generated snow and wind loads in the form of tables, the corresponding schematic sketches are also available in the printout report of RFEM and RSTAB now. These are displayed separately for each load case.
A successful project process involves not only the building owner and the engineer, but also the designers. These days, they also have to design standard connections in steel structures themselves. To do this, the corresponding internal forces of connections are required.