The Dlubal structural analysis software does a lot of work for you. The input parameters, which are relevant for the selected standards, are suggested by the program in accordance with the rules. Furthermore, you can enter response spectra manually.
Load cases of the type Response Spectrum Analysis define the direction in which response spectra act and which eigenvalues of the structure are relevant for the analysis. In the spectral analysis settings, you can define details for the combination rules, damping (if applicable), and zero-period acceleration (ZPA).
Did you know that Equivalent static loads are generated separately for each relevant eigenvalue and excitation direction. These loads are saved in a load case of the Response Spectrum Analysis type and RFEM/RSTAB performs a linear static analysis.
The load cases of the type Response Spectrum Analysis contain the generated equivalent loads. First, the modal contributions have to be superimposed with the SRSS or CQC rule. In this case, you can use the signed results based on the dominant mode shape.
Afterwards, the directional components of earthquake actions are combined with the SRSS or the 100% / 30% rule.
Automatic generation of FE analysis models: The add-on automatically creates a finite element model (FE) of the steel connection in the background.
Consideration of all internal forces: The calculation and design checks include all internal forces (N, Vy, Vz, My, Mz, MT) and are not limited to planar loading.
Automatic load transfer: All load combinations are automatically transferred to the FE analysis model of the connection. The loads are transferred directly from RFEM, so manual data input is not necessary.
Efficient modeling: The add-on saves you time when modeling complex connection situations. You can also save the created FE analysis model and use it further for your own detailed analyses.
Extensible library: An extensive and extensible library with predefined steel connection templates is available.
Wide applicability: The add-on is suitable for connections of any type and shape, compatible with almost all rolled, welded, built-up, and thin-walled cross-sections.
No manual editing of the FE model required by the user, the essential calculation settings can be changed via the configuration settings
Automatic adaptation of the connection geometry, even if the members are subsequently edited, due to the relative relation of the components to each other
Parallel to the input, a plausibility check is carried out by the program to quickly detect missing input or collisions, for example
Graphical display of the connection geometry that is updated in parallel with the input
The program supports you: It determines the bolt forces on the basis of the FE analysis model and evaluates them automatically. The add-on performs the standard-compliant design of bolt resistance for failure cases, such as tension, shear, hole bearing, and punching, and clearly displays all required coefficients.
Do you want to perform weld design? The welds are modeled as elastic-plastic surface elements, and their stresses are read out from the FE analysis model. The plasticity criteria is set in the way that they represent failure according to AISC J2-4, J2-5 (strength of welds), and J2-2 (strength of base metal). The design can be performed with the partial safety factors of the selected National Annex of EN 1993‑1‑8.
The plates in the connection are designed plastically by comparing the existing plastic strain to the allowable plastic strain. The default setting is 5% according to EN 1993‑1‑5, Annex C, but can be adjusted by user-defined specifications, as well as 5% for AISC 360.
You can display all essential results on the FE model. In this case, you can filter the results separately according to the respective components.
Furthemore, RFEM delivers you all design checks in a tabular form, including the display of the formulas used. If you wish, you can transfer the result tables to the RFEM printout report.
Did you know? The structural optimization in the programs RFEM and RSTAB is a completion of the parametric input. It is a parallel process beside the actual model calculation with all its regular calculation and design definitions. The add-on assumes that your model or block is built with a parametric context and is controlled in its entirety by global control parameters of the "optimization" type. Therefore, these control parameters have a lower and upper limit and a step size to delimit the optimization range. If you want to find optimal values for the control parameters, you have to specify an optimization criterion (for example, minimum weight) with the selection of an optimization method (for example, particle swarm optimization).
You can already find the cost and CO2 emission estimation in the material definitions. You can activate both options individually in each material definition. The estimation is based on a unit for unit cost or unit emission for members, surfaces, and solids. In this case, you can select whether to specify the units by weight, volume, or area.