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.
Various design parameters of the cross-sections can be adjusted in the serviceability limit state configuration. The applied cross-section condition for the deformation and crack width analysis can be controlled there.
For this, the following settings can be activated:
- Crack state calculated from associated load
- Crack state determined as an envelope from all SLS design situations
- Cracked state of cross-section - independent of load
- Modeling of the cross-section via elements, sections, arcs, and point elements
- Expansible library of material properties, yield strengths, and limit stresses
- Section properties of open, closed, or non-connected cross-sections
- Ideal section properties of cross-sections consisting of different materials
- Determination of weld stresses in fillet welds
- Stress analysis including design of primary and secondary torsion
- Check of c/t-ratios
- Effective cross-sections according to
- EN 1993-1-5 (including stiffened buckling panels according to Section 4.5)
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EN 1993-1-3
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EN 1999-1-1
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to DIN 18800-2
- Classification according to
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EN 1993-1-1
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EN 1999-1-1
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- Interface with MS Excel to import and export tables
- Printout report
All results can be evaluated and visualized in an appealing numerical and graphical form. Selection functions facilitate the targeted evaluation.
The printout report corresponds to the high standards of RFEM and rstab/rstab-9/what-is-rstab RSTAB. Modifications are updated automatically.
SHAPE-THIN calculates all relevant cross‑section properties, including plastic limit internal forces. Overlapping areas are set close to reality. If cross-sections consist of different materials, SHAPE‑THIN determines the effective cross‑section properties with respect to the reference material.
In addition to the elastic stress analysis, you can perform the plastic design including interaction of internal forces for any cross‑section shape. The plastic interaction design is carried out according to the Simplex Method. You can select the yield hypothesis according to Tresca or von Mises.
SHAPE-THIN performs a cross-section classification according to EN 1993-1-1 and EN 1999-1-1. For steel cross-sections of cross-section class 4, the program determines effective widths for unstiffened or stiffened buckling panels according to EN 1993-1-1 and EN 1993-1-5. For aluminum cross-sections of cross-section class 4, the program calculates effective thicknesses according to EN 1999-1-1.
Optionally, SHAPE‑THIN checks the limit c/t-values in compliance with the design methods el‑el, el‑pl, or pl‑pl according to DIN 18800. The c/t-zones of elements connected in the same direction are recognized automatically.
SHAPE-THIN includes an extensive library of rolled and parameterized cross-sections. They can be composed or supplemented by new elements. It is possible to model a section consisting of different materials.
Graphical tools and functions allow for modeling complex section shapes in the usual way common for CAD programs. The graphical entry provides the option of setting point elements, fillet welds, arcs, parameterized rectangular and circular sections, ellipses, elliptical arcs, parabolas, hyperbolas, spline, and NURBS. Alternatively, it is possible to import a DXF file that is used as the basis for further modeling. You can also use guidelines for modeling.
Furthermore, parameterized input allows you to enter model and load data in a specific way so they depend on certain variables.
Elements can be divided or attached to other objects graphically. SHAPE-THIN automatically divides the elements and provides for an uninterrupted shear flow by introducing dummy elements. In the case of dummy elements, you can define a specific thickness to control the shear transfer.
SHAPE-THIN determines the section properties and stresses of any open, closed, built-up, or non-connected cross-sections.
- Section Properties
- Cross-sectional area A
- Shear areas Ay, Az, Au, and Av
- Centroid position yS, zS
- moments of area 2 degrees Iy, Iz, Iyz, Iu, Iv, Ip, Ip,M
- Radii of gyration iy, iz, iyz, iu, iv, ip, ip,M
- Inclination of principal axes α
- Cross-section weight G
- Cross-section perimeter U
- torsional constants of area degrees IT, IT,St.Venant, IT,Bredt, IT,s
- Location of the shear center yM, zM
- Warping constants Iω,S, Iω,M or Iω,D for lateral restraint
- Max/min section moduli Sy, Sz, Su, Sv, Sω,M with locations
- Section ranges ru, rv, rM,u, rM,v
- Reduction factor λM
- Plastic Cross-Section Properties
- Axial force Npl,d
- Shear forces Vpl,y,d, Vpl,z,d, Vpl,u,d, Vpl,v,d
- Bending moments Mpl,y,d, Mpl,z,d, Mpl,u,d, Mpl,v,d
- Section moduli Zy, Zz, Zu, Zv
- Shear areas Apl,y, Apl,z, Apl,u, Apl,v
- Position of area bisecting axes fu, fv,
- Display of the inertia ellipse
- First moments of area Qu, Qv, Qy, Qz with location of maxima and specification of shear flow
- Warping coordinates ωM
- moments of area (warping areas) Sω,M
- Cell areas Am of closed cross-sections
- Normal stresses σx due to axial force, bending moments, and warping bimoment
- Shear stresses τ from shear forces as well as primary and secondary torsional moments
- Equivalent stresses σv with customizable factor for shear stresses
- Stress ratios, related to limit stresses
- Stresses for element edges or center lines
- Weld stresses in fillet welds
- Section properties of non-connected cross-sections (cores of high-rise buildings, composite sections)
- Shear wall shear forces due to bending and torsion
- Plastic capacity design with determination of the enlargement factor αpl
- Check of the c/t-ratios following the design methods el-el, el-pl or pl-pl according to DIN 18800
RF-CONCRETE Surfaces
The nonlinear calculation is activated by selecting the design method of the serviceability limit state. You can individually select the analyses to be performed as well as the stress-strain diagrams for concrete and reinforcing steel. The iteration process can be influenced by these control parameters: convergence accuracy, maximum number of iterations, arrangement of layers over cross-section depth, and damping factor.
You can set the limit values in the serviceability limit state individually for each surface or surface group. Allowable limit values are defined by the maximum deformation, the maximum stresses, or the maximum crack widths. The definition of the maximum deformation requires additional specification as to whether the non-deformed or the deformed system should be used for the design.
RF-CONCRETE Members
The nonlinear calculation can be applied to the ultimate and the serviceability limit state designs. In addition, you can specify the concrete tensile strength or the tension stiffening between the cracks. The iteration process can be influenced by these control parameters: convergence accuracy, maximum number of iterations, and damping factor.
- Cross-sectional area A
- Shear areas Ay und Az with or without transversal shear
- Centroid position yS, zS
- moments of area 2 degrees Iy, Iz, Iyz, Iu, Iv, Ip
- Inclination of principal axes α
- Radii of gyration iy, iz, iyz, iu, iv, ip
- Torsional constant J
- Cross-section weight G and cross-section perimeter U
- Location of the shear center yM, zM
- Warping constants Iω,S, Iω,M
- Max/min cross-section moduli Sy, Sz, Su, Sv und St
- Plastic cross-section moduli Zy,pl, Zz,pl, Zu,pl, Zv,pl
- Stress function according to Prandtl φ
- Derivation of φ with respect to y and z
- Warping ω
- Cross-section modeling using surfaces, openings, and point areas (reinforcements) limited by polygons
- Automatic or individual arrangement of stress points
- Extensible library of concrete, steel, and reinforcing steel materials
- Cross-section properties of reinforced concrete and composite cross-sections
- Stress analysis with yield hypothesis according to von Mises and Tresca
- Reinforced concrete design according to:
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DIN 1045-1:2008-08
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DIN 1045:1988-07
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ÖNORM B 4700: 2001-06-01
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EN 1992-1-1:2004
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- For the design according to EN 1992-1-1:2004, the following National Annexes are available:
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DIN EN 1992-1-1/NA:2013-04 (Germany)
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NEN-EN 1992-1-1/NA:2011-11 (Netherlands)
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CSN EN 1992-1-1/NA:2006-11 (Czech Republic)
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ÖNORM B 1992-1-1:2011-12 (Austria)
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UNE EN 1992-1-1/NA:2010-11 (Spain)
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EN 1992-1-1 DK NA:2007-11 (Denmark)
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SIST EN 1992-1-1:2005/A101:2006 (Slovenia)
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NF EN 1992-1-1/NA:2007-03 (France)
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STN EN 1992-1-1/NA:2008-06 (Slovakia)
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SFS EN 1992-1-1/NA:2007-10 (Finland)
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BS EN 1992-1-1:2004 (United Kingdom)
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SS EN 1992-1-1/NA:2008-06 (Singapore)
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NP EN 1992-1-1/NA:2010-02 (Portugal)
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UNI EN 1992-1-1/NA:2007-07 (Italy)
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SS EN 1992-1-1/NA:2008 (Sweden)
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PN EN 1992-1-1/NA:2008-04 (Poland)
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NBN EN 1992-1-1 ANB:2010 (Belgium)
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NA to CYS EN 1992-1-1:2004/NA:2009 (Cyprus)
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BDS EN 1992-1-1:2005/NA:2011 (Bulgaria)
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LST EN 1992-1-1:2005/NA:2011 (Lithuania)
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SR EN 1992-1-1:2004/NA:2008 (Romania)
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- In addition to the National Annexes (NA) listed above, you can also define a specific NA, applying user‑defined limit values and parameters.
- Reinforced concrete design for stress-strain distribution, available safety, or direct design
- Results of reinforcement list and total reinforcement area
- Printout report with option to print a short form
RF-CONCRETE Surfaces:
The nonlinear deformation analysis is performed by an iterative process considering the stiffness in cracked and non-cracked sections. The nonlinear reinforced concrete modeling requires definition of material properties varying across the surface thickness. Therefore, a finite element is divided into a certain number of steel and concrete layers in order to determine the cross-section depth.
The mean steel strengths used in the calculation are based on the 'Probabilistic Model Code' published by the JCSS technical committee. It is up to the user whether the steel strength is applied up to the ultimate tensile strength (increasing branch in the plastic area). Regarding material properties, it is possible to control the stress-strain diagram of the compressive and tensile strength. For the concrete compressive strength, you can select a parabolic or a parabolic-rectangular stress-strain diagram. On the tension side of the concrete, it is possible to deactivate the tensile strength as well as to apply a linear-elastic diagram, a diagram according to the CEB-FIB model code 90:1993, and concrete residual tensile strength considering the tension stiffening between the cracks.
Furthermore, you can specify which result values should be displayed after the nonlinear calculation at the serviceability limit state:
- Deformations (global, local based on non-/deformed system)
- Crack widths, depths, and spacing of the top and bottom sides in principal directions I and II
- Stresses of the concrete (stress and strain in principal direction I and II) and of the reinforcement (strain, area, profile, cover, and direction in each reinforcement direction)
RF-CONCRETE Members:
The nonlinear deformation analysis of beam structures is performed by an iterative process considering the stiffness in cracked and non-cracked sections. The material properties of concrete and reinforcing steel used in the nonlinear calculation are selected according to a limit state. The contribution of the concrete tensile strength between the cracks (tension stiffening) can be applied either by means of a modified stress-strain diagram of the reinforcing steel, or by applying a residual concrete tensile strength.
All results can be evaluated and visualized in an appealing numerical and graphical form. Selection functions facilitate the targeted evaluation.
The printout report corresponds to the high standards of RFEM and -rstab RSTAB. Modifications are updated automatically. Furthermore, you can print the reduced report in a short form, including all relevant data and a user-defined cross-section graphic.
- Stresses σ and strains ε of concrete and reinforcement without considering concrete tensile strength (state II)
- Ultimate limit state design (existing safety) or design of defined internal forces
- Location of the neutral axis α0, y0,N, z0,N
- Curvatures ky, kz
- strain in the zero point ε0 and governing strains at the compression edge ε1 and at the tension edge ε2
- Governing steel strain ε2s
- Normal stresses σx due to axial force and bending
- Shear stresses τ due to shear force and torsion
- Equivalent stresses σv compared to limit stress
- Stress ratios related to equivalent stresses
- Normal stress σx due to unit axial force N
- Shear stress τ due to unit shear forces Vy, Vz, Vu, Vv
- Normal stress σx due to unit momentsMy, Mz, Mu, Mv
It is possible to freely model a cross-section using surfaces limited by polygonal lines, including openings and point areas (reinforcements). Alternatively, you can use the DXF interface to import the geometry. An extensive material library facilitates the modeling of composite cross-sections.
Definition of limit diameters and priorities allows for a curtailment of reinforcements. In addition, you can consider the respective concrete covers and prestresses.
- Iterative nonlinear calculation of deformations for beam and plate structures consisting of reinforced concrete by determining the respective element stiffness subjected to the defined loads
- Deformation analyses of cracked reinforced concrete surfaces (state II)
- General nonlinear stability analysis of compression members made of reinforced concrete; for example, according to EN 1992-1-1, 5.8.6
- Tension stiffening of concrete applied between cracks
- Numerous National Annexes available for the design according to Eurocode 2 (EN 1992-1-1:2004 + A1:2014, see EC2 for RFEM)
- Optional consideration of long-term influences such as creep or shrinkage
- Nonlinear calculation of stresses in reinforcing steel and concrete
- Nonlinear calculation of crack widths
- Flexibility due to detailed setting options for basis and extent of calculations
- Graphical representation of results integrated in RFEM; for example, deformation or sag of a flat slab made of reinforced concrete
- Numerical results clearly arranged in tables and graphical display of the results in the model
- Complete integration of results in the RFEM printout report
After the calculation, the module shows clearly arranged tables listing the results of the nonlinear calculation. All intermediate values are included in a comprehensible manner. Graphical representation of design ratios, deformations, concrete and reinforcing steel stresses, crack widths, crack depths, and crack spacing in RFEM facilitates a quick overview of critical or cracked areas.
Error messages or remarks concerning the calculation help you find design problems. Since the design results are displayed by surface or by point including all intermediate results, you can retrace all details of the calculation.
Due to the optional export of input or result tables to MS Excel, the data remain available for further use in other programs. The complete integration of results in the RFEM printout report guarantees verifiable structural design.