The relevant input for the design is defined in the Seismic Configuration. Afterwards, a new Seismic Configuration can be defined by entering a descriptive configuration name, and then selecting the applicable SFRS frame type and member type.
Full integration in RFEM/RSTAB with import of relevant internal forces
Design checks for the elastic-elastic and elastic-plastic methods
Graphical selection of members and sets of members for design
Analysis for several load and design cases
Design based on the buckling field parameters integrated in the cross-section library for the cross-section parts supported on one and both sides
Optional determination of shear stresses according to comment on El. (745)
Possibility to consider the weld thickness in the design of welded cross-sections, which has the effect of a shortening of the cross-section part width
Cross-section optimization with the option to export modified cross-sections
Lines can be imported into RFEM either as lines or members. The names of layers are adopted as the cross-section names, and the first material from the predefined materials is assigned. However, if the section of the Dlubal cross-section library and the material are recognized from the layer name, they are adopted as well.
The seismic design result is categorized into two sections: member requirements and connection requirements.
The "Seismic Requirements" include the Required Flexural Strength and the Required Shear Strength of the beam-to-column connection for moment frames. They are listed in the ‘Moment Frame Connection by Member’ tab. For braced frames, the Required Connection Tensile Strength and the Required Connection Compressive Strength of the brace are listed in the ‘Brace Connection by Member’ tab.
The program provides the performed design checks in tables. The design check details clearly display the formulas and references to the standard.
Use the "Independent mesh preferred" option in the FE mesh settings to create an independent FE mesh for the integrated objects. This allows you to generate a significantly more detailed and precise FE mesh for individual objects that are integrated into one another.
After the design, the results are displayed in different windows sorted by cross-sections, members, sets of members, or x-locations. The corresponding cross-section graphic is always displayed with the result values in tables. In RFEM/RSTAB, they are highlighted by different colors in the structural model. Critical or oversized components can be identified at a glance. You can modify the colors and values assigned.
Result diagrams of a member or a set of members ensure targeted evaluation. It is also possible to represent all intermediate values.
The masses determined during the design are displayed in parts lists for both members and sets of members.
Furthermore, you can export all result tables to MS Excel or in a CSV file. A special transfer menu defines all specifications required for the export.
Full integration in RFEM/RSTAB including import of all relevant internal forces
Intelligent presetting of flexural buckling-specific design parameters
Automatic determination of the distribution of internal forces and classification according to DIN 18800, Part 2
Optional import of buckling lengths from the RF-STABILITY/RSBUCK add-on module. For this, a comfortable graphical selection of the relevant buckling mode is possible
Optimizing Cross-Sections
Optional calculation according to both design methods of DIN 18800, Part 2
Automatic determination of the most unfavorable design location, also for tapered members
Check of c/t-limit values according to DIN 18800, Part 1
Design of any thin-walled RFEM/RSTAB or SHAPE-THIN section for compression and bending without interaction according to the elastic-plastic method
Design of I-shaped rolled and welded sections, I-like sections, box sections, and pipes subjected to bending and compression with iteration according to the elastic-plastic method
Clearly arranged, comprehensible design checks with all intermediate values in the short and long forms
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
In the Modal Analysis add-on, you have the option to automatically increase the sought eigenvalues until reaching a defined effective modal mass factor. All translational directions activated as masses for the modal analysis are taken into account.
Thus, it is possible to easily calculate the required 90% of the effective modal mass for the response spectrum method.
Both optimization methods have one thing in common. At the end of the process, they provide you with a list of model mutations from the stored data. Here you can find the details of the controlling optimization result and the associated value assignment of the optimization parameters. This list is organized in descending order. You can find the assumed best solution shown in the first line. For this, the optimization result with its determined value assignment is closest to the optimization criterion. All add-on results have a utilization < 1. Furthermore, once the analysis is completed, the program will adjust the value assignment to that of the optimal solution for the optimization parameters in the global parameter list.
In the material dialog boxes, you can find the additional tabs "Cost Estimation" and "Estimation of CO2 Emissions". They show you the individual estimated sums of the assigned members, surfaces, and solids per unit weight, volume, and area. Furthermore, these tabs show the total cost and emission of all assigned materials. This gives you a good overview of your project.
Do not lose track of stiffnesses and initial deformations. In the individual load cases or combinations, you have the option to modify the stiffnesses of materials, cross-sections, nodal, line and surface supports, and member and line hinges for all or selected members. You can also consider initial deformations from other load cases or load combinations.
After completing the calculation, you will receive an email with a link to download the calculated file. Large files are compressed into a ZIP archive. Smaller files can be downloaded directly.
As an alternative, there is a link to the calculated file in the Extranet.
The downloaded file is a common RFEM file and can be used for further processing as usual.
Import of relevant information and results from RFEM
Integrated, editable material and section library
Sensible and complete presetting of input parameters
Punching design on columns (all section shapes), wall ends, and wall corners
Automatic recognition of the punching node position from an RFEM model
Detection of curves or splines as a boundary of the control perimeter
Automatic consideration of all slab openings defined in the RFEM model
Construction and graphical display of the control perimeter
Optional design with unsmoothed shear stress along the control perimeter that corresponds to the actual shear stress distribution in the FE model
Determination of the load increment factor β via full-plastic shear distribution as constant factors according to EN 1992‑1‑1, Sect. 6.4.3 (3), based on EN 1992‑1‑1, Fig. 6.21N, or by a user‑defined specification
Numerical and graphical display of results (3D, 2D, and in sections)
Punching design of the slab without punching reinforcement
Qualitative determination of the required punching reinforcement
Design and analysis of the longitudinal reinforcement
Complete integration of results in an RFEM printout report
If you have experimentally determined surface pressures available for a model, you can apply them to a structural model in RFEM 6, process them in RWIND 2, and use them as wind loads in the structural analysis of RFEM 6.
You can find out how to apply the experimentally determined values in this technical article.
In the Geotechnical Analysis add-on, the Hoek-Brown material model is available. The model shows linear-elastic ideal-plastic material behavior. Its nonlinear strength criterion is the most common failure criterion for stone and rocks.
You can enter the material parameters using
Rock parameters directly, or alternatively via
GSI classification.
Detailed information about this material model and the definition of the input in RFEM can be found in the respective chapter Hoek-Brown Model of the online manual for the Geotechnical Analysis add-on.
In a separate dialog box, you can specify extensive detailed settings for the design:
Design Method According to DIN 18800
Design Method 1 According to El. (321)
Design Method 2 According to El. (322)
Analysis method
Elastic-Plastic according to DIN 18800
Elastic-elastic according to a publication by Kretschmar, J./Österrieder, P./beirow, B.
Limit loading of general sections
General sections – these include all cross-sections that cannot be assigned to single or double symmetric I-sections, box sections, or pipe sections – can also be designed according to the equivalent member method against flexural buckling. In this case, however, the plastic cross-section properties are determined without interaction conditions. The allowable application limits for this consideration depend on the ratio of the existing internal force to the fully plastic internal force. Five text boxes provide the option for user-defined control.
Check of limit (c/t)
In this dialog section, you can activate or deactivate the check of c/t ratios.
Treatment of Result Combinations
When designing a result combination, a result set is obtained due to the result superposition on each member location, which makes it impossible to clearly determine the moment factors. In this section, you can thus freely specify a global moment factor for a result combination design. The predefined values are on the safe side, regardless of the design method.
The time history analysis is performed with the modal analysis or the linear implicit Newmark analysis. The time history analysis in this add-on is limited to linear structural systems. Although the modal analysis represents a fast algorithm, it is necessary to use a certain number of eigenvalues to ensure the required accuracy of results.
The implicit Newmark analysis is a very precise method, independent of the number of eigenvalues used, but requires sufficient small time steps for the calculation.
It is necessary to enter the required force-time diagrams. They can be combined in load cases or load combinations of the type Time History Analysis | Time Diagrams with the loading in order to define where and in which direction the force-time diagrams act.
The second option is to enter acceleration-time diagrams, which can be used in the load cases of the Time History Analysis | Accelerogram type.
All calculation parameters are specified in the time history analysis settings. These include, for example, the type of analysis method and the maximum calculation time.
Are you looking for models for your design? Then you have come to the right place at the Dlubal Center. It contains an extensive database with partly parameterized models. These include, for example, trusses, glulam beams, tapered frames, or tower segments. You can import these models and, if necessary, modify them according to your individual requirements. Furthermore, you can save the models as a block for later use.
In RF‑/LTB, the design is usually performed according to the equivalent member method according to DIN 18800, Part 2. However, you can specify extensive detailed settings for the design in a separate dialog box:
Design according to Bird/Heil
Optionally, it is possible to apply the method according to Bird/Heil in the program
the required shear stiffness Sreq
the lateral-torsional buckling load Nki
the critical buckling moment Mki
.
This plastic-plastic calculation method is only valid for lateral and torsional restraints with simple bending with simultaneous load introduction on the upper flange. Further requirements that must be met can be found in the program manual. In case of invalid conditions (for example, biaxial bending), RF-/LTB displays the corresponding error message. In addition, the reduction factorκM for the bending moments My can be set to 1.0 if a restrained rotation axis is present.
Non-Designable Internal Forces
It is possible to neglect non-designable internal forces and thus exclude them from the design if the quotient of the internal force and the fully plastic internal force falls below a certain value. This way, you can neglect, for example, a small moment about the minor axis, thus avoiding the method for biaxial bending.
Allowance according to DIN 18800, Part 2, Element (320) and Element (323)
Automatic determination of ζ
If you want the factor for the determination of the ideal elastic critical moment Mcr to be determined automatically, you can select one of the following types:
Solving the elastic potential numerically
Comparison of moment diagrams
Australian Standard AS 4100-1990
US standard AISC LRFD
When aligning the moment distributions, you can use the library which contains more than 600 moment distributions in tables.