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.
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 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.
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.
Design of tension, compression, bending, shear, and combined internal forces
Stability analysis for flexural buckling and lateral-torsional buckling
Automatic determination of critical buckling loads and critical buckling moments for general load applications and support conditions by means of a special FEA program (eigenvalue analysis) integrated in the module
Optional application of discrete lateral supports to beams
Automatic cross-section classification
Deformation analysis (serviceability)
Cross-section optimization
Wide range of cross-sections available, such as rolled I-sections, C-sections, rectangular hollow sections, angles, double angles (arrangement flange on flange), T-sections. Welded sections: I-shaped (symmetrical and asymmetrical about major axis), channel sections (symmetrical about major axis), rectangular hollow sections (symmetrical and asymmetrical about major axis), angles, round pipes, and round bars
Clearly arranged result tables
Detailed result documentation including references to design equations of the used standard
Various filter and sorting options of results, including result lists by member, cross-sections, x-location, or by load case, load and result combination
Result table of member slenderness and governing internal forces
Do you want to perform the bending failure design? To do this, analyze the governing locations of the column for axial forces and moments. For the shear resistance design, you can also consider the locations with extreme values of shear forces. During the calculation, you determine whether a standard design is sufficient or whether the column with the moments has to be designed according to the second-order theory. You can then determine these moments using the previously entered specifications. The calculation is divided into three parts:
Load-independent calculation steps
Iterative determination of governing loading taking into account a varying required reinforcement
Safety determination of all acting internal forces, including the designed reinforcement
After a successful calculation, the results are displayed in clearly arranged tables. Each intermediate value is absolutely traceable, making the design checks transparent.
Design of members and sets of members for tension, compression, bending, shear, combined internal forces, and torsion
Stability analysis of buckling, torsional, and flexural-torsional buckling
Automatic determination of critical buckling loads and critical buckling moments for general load applications and support conditions by means of a special FEA program (eigenvalue analysis) integrated in the module
Alternative analytical calculation of the critical buckling moment for standard situations
Optional application of discrete lateral supports to beams and continuous members
Automatic cross-section classification
Serviceability limit state design (deflection)
Cross-section optimization
A wide range of available cross-sections, such as rolled I-sections; channel sections; T-sections; angles; rectangular and circular hollow sections; round bars; symmetrical and asymmetrical, parametric I-, T-, and angle sections; double angles
Clearly arranged input and result windows
Detailed result documentation including references to design equations of the used standard
Various filter and sorting options of results, including result lists by member, cross-sections, x-location, or by load case, load and result combination
Result tables of member slenderness and governing internal forces
If you work with loads, find a selection of useful features here. Various load types are available to you for member and surface loads (force, moment, temperature, precamber, and so on). You can assign mmber loads to members, member sets, and member lists. In the case of imperfections, inclination and precamber can be determined precisely according to the Eurocode, the American standard ANSI/AISC 360, the Canadian standard CSA S16, and so on.
Design of members and sets of members for tension, compression, bending, shear, torsion, and combined internal forces
Stability analysis of buckling, torsional, and flexural-torsional buckling
Automatic determination of critical buckling loads and critical buckling moments for general load applications and support conditions by means of a special FEA program (eigenvalue analysis) integrated in the module
Alternative analytical calculation of the critical buckling moment for standard situations
Optional application of discrete lateral supports to beams and continuous members
Automatic cross-section classification
Serviceability limit state design (deflection)
Cross-section optimization
A wide range of available cross-sections, such as rolled I-sections; channel sections; T-sections; angles; rectangular and circular hollow sections; round bars; symmetrical and asymmetrical, parametric I-, T-, and angle sections; double angles
Clearly arranged input and result windows
Detailed result documentation including references to design equations of the used standard
Various filter and sorting options of results, including result lists by member, cross-sections, x-location, or by load case, load and result combination
Result tables of member slenderness and governing internal forces
Do you want to consider other loads as masses in addition to the static loads? The program allows that for nodal, member, line and surface loads. For this, you need to select the Mass load type when defining the load of interest. Define a mass or mass components in the X, Y, and Z directions for such loads. For nodal masses, you have an additional option to also specify moments of inertia X, Y, and Z in order to model more complex mass points.
Design of members and sets of members for compression, bending, shear, and combined actions
Stability analysis of buckling and lateral-torsional buckling
Automatic determination of critical buckling loads and critical buckling moments for general load applications and support conditions by means of a special FEA program (eigenvalue analysis) integrated in the module
Optional application of discrete lateral supports to beams
Automatic cross-section classification (Class 1 to 4)
Deformation analysis (serviceability)
Cross-section optimization
A wide range of available cross-sections, such as rolled I-sections; channel sections; T-sections; angles; rectangular and circular hollow sections; round bars; symmetrical and asymmetrical, parametric I-, T-, and angle sections; double angles
Optional import of buckling lengths from RF-STABILITY/RSBUCK
Detailed result documentation including references to design equations of the used standard
Various filter and sorting options of results including result lists by member, cross-section, x-location, or by load cases, load and result combinations
Result table of member slenderness and governing internal forces
It is necessary to enter material, load, and combination data in RFEM/RSTAB in compliance with the design concept specified by the standard SANS 10162-1:2011. The RFEM/RSTAB material library already contains materials relevant for the South African standard.
The RF-/STEEL SANS add-on module requires members and sets of members as well as load cases, load combinations, and result combinations to be designed. In the subsequent input windows, you can adjust preset definitions of lateral intermediate supports and effective lengths.
In the case of continuous members, it is possible to define individual support conditions and eccentricities of each intermediate node of single members. A special FEA tool then determines the critical loads and moments required for the stability analysis in these situations.
Design of moment resistant and simple joints of I-shaped rolled cross-sections according to Eurocode 3:
Moment-resisting end plate connections (type IH/IM)
Moment resistant purlin splices (PM type)
Simple joints with angle cleat and long angles (IW and IG types)
Simple joints with header end plates mounted either on web only or on web and flange (IS type)
Check of coped connections (IK) in combination with pinned end plates (IS) and angle connections (IW)
Automatic design of required joint with bolt sizes (all types)
Check of required thickness of load-bearing members for shear connections
Results of all required structural details such as appliances, hole arrangements, necessary extensions, a number of bolts, end plate dimensions, and welds
Results including stiffnesses Sj,ini of bending-resistant connections
Documentation of available loading and comparison with resistances
Results of design ratio for each individual joint
Automatic determination of governing internal forces for several load cases and connection nodes
Design of members and sets of members for tension, compression, bending, shear, combined internal forces, and torsion
Stability analysis of buckling and lateral-torsional buckling
Automatic determination of critical buckling loads and critical buckling moments for general load applications and support conditions by means of a special FEA program (eigenvalue analysis) integrated in the module
Alternative analytical calculation of the critical buckling moment for standard situations
Optional application of discrete lateral supports to beams and continuous members
Automatic cross-section classification (compact, noncompact, and slender)
Serviceability limit state design (deflection)
Cross-section optimization
A wide range of available cross-sections, such as rolled I-sections, channel sections, T-sections, angles, rectangular and circular hollow sections, round bars, symmetrical, asymmetrical, parameterized I-, T-, and angle sections, as well as user-defined SHAPE‑THIN sections
Clearly arranged input and result windows
Detailed result documentation including references to design equations of the used standard
Various filter and sorting options of results including result lists by member, cross-section, x-location, or by load cases, load and result combinations
Result table of member slenderness and governing internal forces
It is necessary to enter material, load, and combination data in RFEM/RSTAB in compliance with the design concept specified by the Code of Practice for the Structural Use of Steel 2011 (Buildings Department – Hong Kong).
The RF-/STEEL HK add-on module requires members and sets of members as well as load cases, load combinations, and result combinations to be designed. In the subsequent input windows, you can adjust preset definitions of lateral intermediate supports and effective lengths.
In the case of continuous members, it is possible to define individual support conditions and eccentricities of each intermediate node of single members. A special FEA tool then determines the critical loads and moments required for the stability analysis in these situations.
Design of tension, compression, bending, shear, and combined internal forces
Stability analysis for flexural buckling and lateral-torsional buckling
Automatic determination of critical buckling loads and critical buckling moments for general load applications and support conditions by means of a special FEA program (eigenvalue analysis) integrated in the module
Optional application of discrete lateral supports to beams
Automatic cross-section classification
Deformation analysis (serviceability)
Cross-section optimization
Wide range of cross-sections available, such as rolled I-sections, C-sections, rectangular hollow sections, angles, double angles (arrangement flange on flange), T-sections. Welded sections: I-shaped (symmetrical and asymmetrical about major axis), channel sections (symmetrical about major axis), rectangular hollow sections (symmetrical and asymmetrical about major axis), angles, round pipes, and round bars
Clearly arranged result tables
Detailed result documentation including references to design equations of the used standard
Various filter and sorting options of results, including result lists by member, cross-sections, x-location, or by load case, load and result combination
Result table of member slenderness and governing internal forces
It is necessary to enter material, load, and combination data in RFEM/RSTAB in compliance with the design concept specified by CSA S16. The RFEM/RSTAB material library already contains materials relevant for the Canadian standard.
RFEM/RSTAB automatically creates the corresponding load combinations according to the Canadian standard. However, you can also create all the combinations manually in RFEM/RSTAB. The RF-/STEEL CSA add-on module requires members and sets of members, as well as load cases, load combinations, and result combinations to be designed.
In the subsequent input windows, you can adjust preset definitions of lateral intermediate supports and effective lengths. In the case of continuous members, it is possible to define individual support conditions and eccentricities of each intermediate node of single members. A special FEA tool then determines the critical loads and moments required for the stability analysis in these situations.
Integration in RFEM/RSTAB with automatic geometry recognition and transfer of internal forces
Optional manual definition of connections
Extensive library of hollow sections for chords and struts:
Round sections
Square sections
Rectangular sections
Implemented steel grades: S 235, S 275, S 355, S 420, S 450, and S 460
Various types of connections available, depending on the standard specifications:
K connection (gap/overlapping)
KK connection (spatial)
N connection (gap/overlapping)
KT connection (gap/overlapping)
DK connection (gap/overlapping)
T connection (planar)
TT connection (spatial)
Y connection (planar)
X connection (planar)
XX connection (spatial)
Selection of partial safety factors according to the National Annex for Germany, Austria, Czech Republic, Slovakia, Poland, Slovenia, Switzerland, or Denmark
Adjustable angles between struts and chords
Optional chord rotation of 90° for rectangular hollow sections
Consideration of gaps between struts or overlapping struts
Optional consideration of additional nodal forces
Design of the connection as the maximum load-bearing capacity of the struts of a truss for axial forces and bending moments
Design of tension, compression, bending, shear, and combined internal forces
Stability analysis for flexural buckling and lateral-torsional buckling
Automatic determination of critical buckling loads and critical buckling moments for general load applications and support conditions by means of a special FEA program (eigenvalue analysis) integrated in the module
Optional application of discrete lateral supports to beams
Automatic cross-section classification (Class 1 to 3)
Deformation analysis (serviceability)
Cross-section optimization
Wide range of cross-sections available, such as rolled I-sections, C-sections, rectangular hollow sections, angles, double angles (arrangement flange on flange), T-sections. Welded sections: I-shaped (symmetrical and asymmetrical about major axis), channel sections (symmetrical about major axis), rectangular hollow sections (symmetrical and asymmetrical about major axis), angles, round pipes, and round bars
Clearly arranged result tables
Detailed result documentation including references to design equations of the used standard
Various filter and sorting options of results, including result lists by member, cross-sections, x-location, or by load case, load and result combination
Result table of member slenderness and governing internal forces
It is necessary to enter material, load, and combination data in RFEM/RSTAB in compliance with the design concept specified by SIA 263.
The RFEM/RSTAB material library already contains the relevant materials for SIA. Furthermore, RFEM/RSTAB automatically creates the corresponding load combinations according to SIA 260. However, you can also create all the combinations manually in RFEM/RSTAB.
The RF-/STEEL SIA add-on module requires members and sets of members, as well as load cases, load combinations, and result combinations to be designed. In the next steps, you can adjust the preset definitions of lateral intermediate supports and effective lengths.
In the case of continuous members, it is possible to define individual support conditions and eccentricities of each intermediate node of single members. A special FEA tool then determines the critical loads and moments required for the stability analysis in these situations.