In the Steel Joints add-on, you can connect circular hollow sections using welds.
It is possible to connect the circular sections to each other or to planar structural components. The fillets of standard and thin-walled sections can also be connected with a weld.
In the Steel Design add-on, you can perform the stability and cross-section design checks of cold-formed sections according to EN 1993‑1‑3 in compliance with Sections 6.1.2 – 6.1.5 and 6.1.8 – 6.1.10.
In the Steel Joints add-on, you can classify the joint stiffnesses.
In addition to the initial stiffness, the table also shows the limit values for hinged and rigid connections for the selected internal forces N, My, and/or Mz. The resulting classification is then displayed in tables as "hinged", "semi-rigid", or "rigid".
In the "Steel Joints" add-on, you can consider preloaded bolts in all components during the calculation. You can easily activate the preloading using the check box in the bolt parameters, and it has an impact on the stress-strain analysis as well as the stiffness analysis.
Preloaded bolts are special bolts used in steel structures to generate a high clamping force between the connected structural components. This clamping force causes friction between the structural components, which allows for the transfer of forces.
Functionality Preloaded bolts are tightened with a certain torque, causing them to stretch and generate a tensile force. This tensile force is transferred to the connected components and leads to a high clamping force. The clamping force prevents the connection from loosening and ensures safe force transmission.
Advantages
High load-bearing capacity: Preloaded bolts can transfer large forces.
Low deformation: They minimize the deformation of the connection.
Fatigue strength: They are resistant to fatigue.
Easy assembly: They are relatively easy to assemble and disassemble.
Analysis and Design The calculation of preloaded bolts is performed in RFEM using the FE analysis model generated by the "Steel Joints" add-on. It takes into account the clamping force, friction between structural components, shear strength of bolts, and load-bearing capacity of the structural components. The design is carried out according to DIN EN 1993‑1‑8 (Eurocode 3) or the US standard ANSI/AISC 360‑16. You can save the created analysis model, including the results, and use it as an independent RFEM model.
The initial stiffness Sj,ini is a crucial parameter for evaluating whether a connection can be characterized as rigid, semi-rigid, or pinned.
In the "Steel Joints" add-on, you can calculate the initial stiffness Sj,ini according to Eurocode (EN 1993‑1‑8, Section 5.2.2) and AISC (AISC 360-16, Cl. E3.4) with regard to the internal forces N, My, and/or Mz.
The optional automatic transfer of initial stiffnesses allows for a directly transfer as member hinge stiffnesses in RFEM. The entire structure is then recalculated and the resulting internal forces are automatically adopted as loads in the analysis and design of the connection models.
This automated iteration process eliminates the need for manual export and import of data, reducing the amount of work and minimizing potential sources of error.
The design of cold-formed steel members according to the AISI S100-16 / CSA S136-16 is available in RFEM 6. Design can be accessed by selecting “AISC 360” or “CSA S16” as the standard in the Steel Design Add-on. “AISI S100” or “CSA S136” is then automatically selected for the cold-formed design.
RFEM applies the Direct Strength Method (DSM) to calculate the elastic buckling load of the member. The Direct Strength Method offers two types of solutions, numerical (Finite Strip Method) and analytical (Specification). The FSM signature curve and buckling shapes can be viewed under Sections.
In the Steel Joint add-on, you can design the connections of members with composite cross-sections. Furthermore, you can perform joint design checks for almost all thin-walled cross-sections in the RFEM library.
Here, the weld design becomes child's play. Using the specially developed material model "Orthotropic | Plastic | Weld (Surfaces)", you can calculate all stress components plastically. The stress τperpendicular is also considered plastically.
Using this material model you can design welds closer to reality and more efficiently.
Using the "Connecting Plate" component, you can automatically create a new gusset plate in the Steel Joints add-on. This saves you separate components, and the other elements, such as a cap plate and a slide plate, are thus automatically taken into account with their dimensions.
If a weld seam connects two plates with different materials, it is possible to select from a combo box in the Steel Joints add-on which one of both materials should be used for the weld seam.
Would you like to perform cross-section design checks for cold-formed steel members according to EN 1993‑1‑3? No matter if you design the cold-formed sections from the cross-section library or the general cold-formed (non-perforated) sections from RSECTION – your structural analysis program helps you to determine the effective cross-section, taking into account the local buckling and instability. You can also perform a cross-section check according to EN 1993‑1‑3, 6.1.6. In this case, the internal forces from the calculation using Torsional Warping (7 DOF) are taken into account by means of the equivalent stress check
In the case of rectangular cross-sections, you can usually achieve a direct connection by using welds. However, you can also connect them to other cross-sections in the same way. Furthermore, other components such as end plates help you to connect the rectangular cross-sections to other structural components.
When performing a design according to EN 1993‑1‑3, it is possible to graphically display a mode shape for the distortional buckling of a cross-section, and for the RSECTION cross-sections.
The mode shape can also be output in RSECTION 1 for library cross-sections.
Design of a frame connection with taper and stiffened members. A stress analysis and a buckling stability analysis were carried out for the connection. To display the buckling results, the connection was converted into a separate model.
A wide range of cross-sections, such as rectangular sections, square sections, T‑sections, circular sections, built-up cross-sections, irregular parametric cross-sections, and many others (suitability for design depends on the selected standard)
Design of cross-laminated timber (CLT)
Design of timber-based materials and laminated veneer lumber according to EC 5
Design of tapered and curved members (design method according to the standard)
Adjustment of the essential design factors and standard parameters is possible
Flexibility due to detailed setting options for basis and extent of calculations
Fast and clear results output for an immediate overview of the result distribution after the design
Detailed output of the design results and essential formulas (comprehensible and verifiable result path)
Numerical results clearly arranged in tables and graphical display of the results in the model
Integration of the output into the RFEM/RSTAB printout report
Did you use the eigenvalue solver of the add-on to determine the critical load factor within the stability analysis? If so, you can then display the governing mode shape of the object to be designed as a result. The eigenvalue solver is available here for the lateral-torsional buckling analysis, depending on the design standard used.
If your design is successful, the relaxed part of your work follows. Because the program does many processes for you. For example, the performed design checks are displayed in a table. It shows you all the result details. Due to the clearly presented design formulas, you will be able to understand the results without any problems. There is no "black box" effect here.
The design checks are carried out at all governing locations of the members and displayed graphically as a result diagram. Furthermore, detailed graphics, such as the stress distribution on a cross-section or the governing mode shape, are available for you in the result output.
All input and result data are part of the RFEM/RSTAB printout report. You can select the report contents and extent specifically for the individual design checks.
In RFEM/RSTAB, you have the option to generate and then calculate the load or result combinations required for the serviceability limit state. You can select these design situations for the deflection analysis in the Steel Design add-on. The calculated deformation values are determined accordingly at each location of a member, depending on the specified precamber and reference system. Finaly, you can compare these deformation values with the limit values.
Did you know? You can specify the deformation limit value individually for each structural component in Serviceability Configuration. Define the maximum deformation depending on the reference length as the allowable limit value. By defining design supports, you can segment the components in order to determine the corresponding reference length automatically for each design direction.
Based on the position of the assigned design supports, the distinction between beams and cantilevers is made automatically so the limit value can be determined accordingly.
You can find the serviceability limit state design checks in the result tables of the Steel Design add-on. You can display the design results with all the details at each location of the designed members. Furthermore, graphics are available for you with the result diagrams of the design ratios. This gives you a good overview.
You can also integrate all result tables and graphics into the global printout report of RFEM/RSTAB as a part of the steel design results. Thus, you can display and document the deformations of the entire structure as a part of the RFEM/RSTAB functionality independent of the add-on.
The structural analysis programs RFEM/RSTAB offer you a wide range of automated functions that make your dayily work easier. One of them is the automatic generation of load and result combinations for the accidental design situation of fire design. The members to be designed with the corresponding internal forces are imported directly from RFEM/RSTAB. You don't need to do anything else. The program has also already stored all information about the material and cross-section for you.
By assigning a fire resistance configuration to the members to be designed, you define the parameters relevant for the fire resistance design. Here you can manually specify the critical steel temperature at the design time. Or let the program to determine the temperature determined automatically for a specified fire duration. You can select from various fire temperature curves and fire protection measures. It is also possible to make further detailed settings, such as the definition of the fire exposure on all sides or three sides