At first, the governing joint designs are arranged in groups and displayed with the basic geometry of the joint in the first result window. In the other result tables, you can see all fundamental design details such as the load-carrying capacity of anchors, stresses in welds, and others.
Dimensions, material specifications, and welds that are important for the construction of the connection are visible immediately and can be printed out. It is possible to visualize the connections in RF-/JOINTS Steel - Column Base or in the RFEM/RSTAB model.
All graphics can be included in the RFEM/RSTAB printout report or printed directly. Due to the scaled output, an optimal visual check is possible as early as in the design phase.
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.
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.
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.
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.
Graphical display of the connection geometry that is updated in parallel with the input
The Steel Joints Template included in the add-on allows you to select from several connection types and, and once selected, it will be applied to your model.
Wide range of cross-section shapes: Includes I-sections, channel sections, angles, T-sections, built-up cross-sections, RHS (rectangular hollow sections), and thin-walled sections
The Template covers connections from three general categories: Rigid, Pinned, Truss
Automatic adaptation of the connection geometry, even if the structural components are subsequently edited, based on the relative relation of the components
You can perform the calculation of the warping torsion on the entire system. Thus, you consider the additional 7th degree of freedom in the member calculation. The stiffnesses of the connected structural elements are automatically taken into account. It means, you don't need to define equivalent spring stiffnesses or support conditions for a detached system.
You can then use the internal forces from the calculation with warping torsion in the add-ons for the design. Consider the warping bimoment and the secondary torsional moment, depending on the material and the selected standard. A typical application is the stability analysis according to the second-order theory with imperfections in steel structures.
Did you know that The application is not limited to thin-walled steel cross-sections. Thus, it is possible for you, for example, to perform the calculation of the ideal overturning moment of beams with solid timber cross-sections.
The Hinged Column Footing category provides four different base plate connections:
Simple column base
Tapered column base
Column base for rectangular hollow sections
Column base for circular hollow sections
The Restraint Column Footing category provides five different joint layouts of I-sections:
Base plate without stiffening
Base plate with stiffeners in center of flanges
Base plate with stiffeners on both sides of column
Base plate with channel sections
Pocket foundation
All connection types include a base plate welded around a steel column. Connections with anchors are set in concrete within the foundation. You can select anchor types M12 – M42 with steel grades of 4.6 – 10.9. The top and bottom sides of the anchors can be provided with round or angled sheets for better load distribution or anchorage. In addition, you can use rectangular or circular anchor heads with threads applied at the member ends.
The material and thickness of the grout layer, as well as the dimensions and material of the footing, can be set freely. Furthermore, you can define edge reinforcement of the footing. For a better transfer of shear forces, it is possible to arrange a shear key (cleat) on the bottom side of the base plate.
Shear forces are transferred by a cleat, anchors, or friction. You can combine the individual components.
After you have selected the anchorage type and the design standard in the first input window, define the node in Window 1.2 that is to be imported from RFEM/RSTAB and where the footing anchorage is to be designed.
Optionally, you can define the column cross-section and material manually. In the next input windows, you can define the parameters of the base point, such as The loading is imported from RFEM/RSTAB or, in the case of a manual joint definition, the loads are entered.
In the Steel Joints add-on, you can design connections according to the American standard ANSI/AISC 360‑16. The following design procedures are integrated:
Consideration of 7 local deformation directions (ux, uy, uz, φx, φy, φz, ω) or 8 internal forces (N, Vu, Vv, Mt,pri, Mt,sec, Mu, Mv, Mω) when calculating member elements
Usable in combination with a structural analysis according to linear static, second-order, and large deformation analysis (imperfections can also be taken into account)
In combination with the Stability Analysis add-on, allows you to determine critical load factors and mode shapes of stability problems such as torsional buckling and lateral-torsional buckling
Consideration of end plates and transverse stiffeners as warping springs when calculating I-sections with automatic determination and graphical display of the warping spring stiffness
Graphical display of the cross-section warping of members in the deformation
In the Steel Joints add-on, you can classify the joint stiffness.
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".
The results of warping torsion analysis are displayed in RF-/STEEL AISC and RF-/STEEL EC3 in the usual way. Among other results, the corresponding result windows include the critical warping and torsional values, internal forces, and design summary.
The graphical display of mode shapes (incl. warping) enables a realistic assessment of buckling behavior.
At first, the governing joint designs are arranged in groups and displayed with the basic geometry of the joint in the first result window. In the other result tables, you can see all fundamental design details such as the bearing resistance, shearing, sliding, and others.
Dimensions, material properties, and welds important for the connection construction are displayed immediately and can be printed directly. It is possible to visualize the connections in RF-/JOINTS Steel - Tower or in the RFEM/RSTAB model.
All graphics can be included in the RFEM/RSTAB printout report or printed directly. Due to the scaled output, an optimal visual check is possible as early as in the design phase.
In this case, you calculate the critical load factor for all analyzed load combinations and the selected number of mode shapes for the connection model. Compare the smallest critical load factor with the limit value 15 from the standard EN 1993‑1‑1, Clause 5. Furthermore, you can make user-defined adjustment of the limit value. As a result of the stability analysis, the program displays the corresponding mode shapes graphically.
For the stability analysis, RFEM uses the adapted surface model to specifically recognize the local buckling shapes. You can also save and use the model of the stability analysis, including the results, as a separate model file.
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.
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.
All joint types are considered with the moment release at the column flange, or at the column web in the case of a rotated column. Therefore, the module determines the eccentric moment of a web cleat and fin plate connection, which additionally affects the bolt group at the girder flange.
Further eccentric moments may result from the locations of the angles and sheets. In the case of cleat connection, the forces are transferred separately. Shear forces act on the cleat; tension forces and stabilizing moment are assigned to the bolts. Before the calculation, the connection is checked for geometrical plausibility; for example, the bolt hole spacing and edge distance of the bolts.