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
You can use the "Plate Cut" component to cut plates (for example, gusset plates, fin plates, and so on). Various cutting methods are available:
Plane: The cut is performed on the closest surface to the reference plate.
Surface: Only the intersecting parts of plates are cut.
Bounding Box: The outermost dimension consisting of width and height is cut out of the plate as a rectangle.
Convex Hull: The outer hull of the cross-section is used for the plate cut. If there are fillets at the corner nodes of the cross-section, the cut is adapted to them.
In the design add-ons (for example, Concrete Design, Steel Design, Timber Design, and so on), you can optimize cross-sections.
The optimization can be performed, for example, for standard cross-sections of a series, or for the width, height, and so on, in the case of parametric cross-sections.
For timber surfaces with the "Constant" thickness type, the crack factor kcr and thus the negative influence of cracks on the shear capacity is taken into account.
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
Did you know? In contrast to other material models, the stress-strain diagram for this material model is not antimetric to the origin. You can use this material model to simulate the behavior of steel fiber-reinforced concrete, for example. Further information about modeling steel fiber-reinforced concrete can be found in this technical article:
Determining Material Properties of Steel Fiber-Reinforced Concrete and Their Application in RFEM
In this material model, the isotropic stiffness is reduced with a scalar damage parameter. This damage parameter is determined from the stress curve defined in the Diagram. This does not take the direction of the principal stresses into account; rather, the damage occurs in the direction of the equivalent strain, which also covers the third direction perpendicular to the plane. The tension and compression areas of the stress tensor are treated separately. In this case, different damage parameters apply.
The "Reference element size" controls how the strain in the crack area is scaled to the length of the element. With the default value zero, no scaling is performed. Thus, the material behavior of the steel fiber-reinforced concrete is modeled realistically.
You determine the deformation for members and surfaces, taking into account the cracked (state II) or non-cracked (state I) reinforced concrete cross-section. When determining the stiffness, you can consider "tension stiffening" between the cracks according to the design standard used.
Within a member, you can define the integration width and effective slab width of T-beams (ribs) with different widths. The member is divided into segments. You can either grade or specify the transition between the different flange widths as linearly variable. Furthermore, the program allows you to consider the defined surface reinforcement as a flange reinforcement for the reinforced concrete design of a rib.
Was your design successful? Then just sit back and relax. You benefit from the numerous functions in RFEM also here. The program gives you the maximum stresses of the masonry surfaces, whereby you can display the results in detail at each FE mesh point.
Moreover, you can insert sections in order to carry out a detailed evaluation of the individual areas. Use the display of the yield areas to estimate the cracks in the masonry.
Deformation analyses of reinforced concrete surfaces without or with cracks (state II) by applying the approximation method (for example, deformation analysis according to ACI 318-19, 24.3.2.5 or EN 1992‑1‑1, Cl. 7.4.3 )
Tension stiffening of concrete applied between cracks
Optional consideration of creep and shrinkage
Graphical representation of results integrated in RFEM, such as deformation or sag of a flat slab
Clear numerical result display in the detail dialog box
Complete integration of results in the RFEM printout report
Are you looking for a deformation calculation? Check the Serviceability Configuration, where it can be activated. You can also control the consideration of long-term effects (creep and shrinkage) and tension stiffening between cracks in the dialog box above. The creep coefficient and shrinkage strain are calculated using the specified input parameters, or you can define them individually.
Furthermore, you can specify the deformation limit value individually for each structural component. The max. deformation is defined as the allowable limit value. In addition, you have to specify whether you want to use the undeformed or the deformed system for the design check.
The standards already specify the approximation methods (for example, deformation calculation according to EN 1992‑1‑1, 7.4.3, or ACI 318‑19, 24.3.2.5) that you need for your deformation calculation. In this case, the so-called effective stiffnesses are calculated in the finite elements in accordance with the existing limit state with / without cracks. You can then use these effective stiffnesses to determine the deformations by means of another FEM calculation.
Consider a reinforced concrete cross-section for the calculation of the effective stiffnesses of the finite elements. Based on the internal forces determined for the serviceability limit state in RFEM, you can classify the reinforced concrete cross-section as "cracked" or "uncracked". Do you consider the effect of the concrete between the cracks? In this case, this is done by means of a distribution coefficient (for example, according to EN 1992‑1‑1, Eq. 7.19, or ACI 318‑19, 24.3.2.5). You can assume the material behavior for the concrete to be linear-elastic in the compression and tension zone until reaching the concrete tensile strength. This procedure is sufficiently precise for the serviceability limit state.
When determining the effective stiffnesses, you can take into accout the creep and shrinkage at the "cross-section level." You don't need to consider the influence of shrinkage and creep in statically indeterminate systems in this approximation method (for example, tensile forces from shrinkage strain in systems restrained on all sides are not determined and have to be considered separately). In summary, the deformation calculation is carried out in two steps:
Calculation of effective stiffnesses of the reinforced concrete cross-section assuming linear-elastic conditions
Calculation of the deformation using the effective stiffnesses with FEM
The material model Orthotropic Masonry 2D is an elastoplastic model that additionally allows softening of the material, which can be different in the local x- and y-directions of a surface. The material model is suitable for (unreinforced) masonry walls with in-plane loads.
SHAPE‑THIN determines the effective cross-sections according to EN 1993‑1‑3 and EN 1993‑1‑5 for cold-formed sections. You can optionally check the geometric conditions for the applicability of the standard specified in EN 1993‑1‑3, Section 5.2.
The effects of local plate buckling are considered according to the method of reduced widths, and the possible buckling of stiffeners (instability) is considered for stiffened sections according to EN 1993‑1‑3, Section 5.5.
As an option, you can perform an iterative calculation to optimize the effective cross-section.
You can display the effective cross-sections graphically.
Read more about designing cold-formed sections with SHAPE-THIN and RF-/STEEL Cold-Formed Sections in the technical article "Design of Thin-Walled, Cold-Formed C-Section According to EN 1993‑1‑3".
Import of materials, cross-sections, and internal forces from RFEM/RSTAB
Steel design of thin‑walled cross‑sections according to EN 1993‑1‑1:2005 and EN 1993‑1‑5:2006
Automatic classification of cross-sections according to EN 1993-1-1:2005 + AC:2009, Cl. 5.5.2, and EN 1993-1-5:2006, Cl. 4.4 (cross-section class 4), with optional determination of effective widths according to Annex E for stresses under fy
Integration of parameters for the following National Annexes:
DIN EN 1993-1-1/NA:2015-08 (Germany)
ÖNORM B 1993-1-1:2007-02 (Austria)
NBN EN 1993-1-1/ANB:2010-12 (Belgium)
BDS EN 1993-1-1/NA:2008 (Bulgaria)
DS/EN 1993-1-1 DK NA:2015 (Denmark)
SFS EN 1993-1-1/NA:2005 (Finland)
NF EN 1993-1-1/NA:2007-05 (France)
ELOT EN 1993-1-1 (Greece)
UNI EN 1993-1-1/NA:2008 (Italy)
LST EN 1993-1-1/NA:2009-04 (Lithuania)
UNI EN 1993-1-1/NA:2011-02 (Italy)
MS EN 1993-1-1/NA:2010 (Malaysia)
NEN EN 1993-1-1/NA:2011-12 (Netherlands)
NS EN 1993-1-1/NA:2008-02 (Norway)
PN EN 1993-1-1/NA:2006-06 (Poland)
NP EN 1993-1-1/NA:2010-03 (Portugal)
SR EN 1993-1-1/NB:2008-04 (Romania)
SS EN 1993-1-1/NA:2011-04 (Sweden)
SS EN 1993-1-1/NA:2010 (Singapore)
STN EN 1993-1-1/NA:2007-12 (Slovakia)
SIST EN 1993-1-1/A101:2006-03 (Slovenia)
UNE EN 1993-1-1/NA:2013-02 (Spain)
CSN EN 1993-1-1/NA:2007-05 (Czech Republic)
BS EN 1993-1-1/NA:2008-12 (the United Kingdom)
CYS EN 1993-1-1/NA:2009-03 (Cyprus)
In addition to the National Annexes (NA) listed above, you can also define a specific NA, applying user‑defined limit values and parameters.
Automatic calculation of all required factors for the design value of flexural buckling resistance Nb,Rd
Automatic determination of the ideal elastic critical moment Mcr for each member or set of members on every x-location according to the Eigenvalue Method or by comparing moment diagrams. You only have to define the lateral intermediate supports.
Design of tapered members, unsymmetric sections or sets of members according to the General Method as described in EN 1993-1-1, Cl. 6.3.4
In the case of the General Method according to Cl. 6.3.4, optional application of "European lateral-torsional buckling curve" according to Naumes, Strohmann, Ungermann, Sedlacek (Stahlbau 77 [2008], pp. 748‑761)
Rotational restraints can be taken into account (trapezoidal sheeting and purlins)
Optional consideration of shear panels (for example, trapezoidal sheeting and bracing)
RF-/STEEL Warping Torsion module extension (license required) for stability analysis according to the second-order analysis as stress analysis including consideration of the 7th degree of freedom (warping)
Module extension RF-/STEEL Plasticity (license required) for plastic analysis of cross‑sections according to Partial Internal Forces Method (PIFM) and Simplex Method for general cross‑sections (in connection with the RF‑/STEEL Warping Torsion module extension, it is possible to perform the plastic design according to the second‑order analysis)
Module extension RF-/STEEL Cold-Formed Sections (license required) for ultimate and serviceability limit state designs for cold-formed steel members according to the EN 1993-1-3 and EN 1993-1-5 standards
ULS design: Selection of fundamental or accidental design situations for each load case, load combination, or result combination
SLS design: Selection of characteristic, frequent, or quasi-permanent design situations for each load case, load combination, or result combination
Tension analysis with definable net cross-section areas for member start and end
Weld designs of welded cross-sections
Optional calculation of warp spring for nodal support on sets of members
Graphic of design ratios on cross-section and in RFEM/RSTAB model
Determination of governing internal forces
Filter options for graphical results in RFEM/RSTAB
Representation of design ratios and cross‑section classes in the rendered view
Color scales in result windows
Automatic cross-section optimization
Transfer of optimized cross-sections to RFEM/RSTAB
Parts lists and quantity surveying
Direct data export to MS Excel
Verifiable printout report
Possibility to include the temperature curve in the report
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.
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.
Before the calculation starts, you should check the input data using the program function. Then, the CONCRETE add‑on module searches the results of relevant load cases, load as well as result combinations. If these cannot be found, RSTAB starts the calculation to determine the required internal forces.
Considering the selected design standard, the required reinforcement areas of the longitudinal and the shear reinforcement as well as the corresponding intermediate results are calculated. If the longitudinal reinforcement determined by the ultimate limit state design is not sufficient for the design of the maximum crack width, it is possible to increase the reinforcement automatically until the defined limit value is reached.
The design of potentially unstable structural components is possible using a nonlinear calculation. According to a respective standard, different approaches are available.
The fire resistance design is performed according to a simplified calculation method in compliance with EN 1992‑1‑2, 4.2. The module uses the zone method mentioned in Annex B2. Furthermore, you can consider the thermal strains in the longitudinal direction and the thermal precamber additionally arising from asymmetrical effects of fire.
The deformation analysis according to the approximation method defined in standards (for example, deformation analysis according to EN 1992‑1‑1, 7.4.3) applies to the calculation of "effective stiffnesses" in the finite elements in accordance with the existing limit state of the concrete with or without cracks. These stiffnesses are used to determine the surface deformation by repeated FEM calculation.
The effective stiffness calculation of finite elements takes into account a reinforced concrete cross-section. Based on the internal forces determined for the serviceability limit state in RFEM, the program classifies the reinforced concrete cross-section as 'cracked' or 'uncracked'. If the tension stiffening at a section should be considered as well, a distribution coefficient (according to EN 1992-1-1, Eq. 7.19, for example) is used. The material behavior for the concrete is assumed to be linear-elastic in the compression and tension zone until the concrete tensile strength is reached. This is reached exactly in the serviceability limit state.
When determining the effective stiffnesses, creep and shrinkage are taken into account at the "cross-section level". The influence of shrinkage and creep in statically indeterminate systems is not taken into account in this approximation method (for example, tensile forces from shrinkage strain in systems restrained on all sides are not determined and must be considered separately). In summary, RF-CONCRETE Deflect calculates deformations in two steps:
Calculation of effective stiffnesses of the reinforced concrete cross-section assuming linear-elastic conditions
Calculation of the deformation using the effective stiffnesses with FEM
The module extension EC2 for RSTAB enables design of reinforced concrete according to EN 1992-1-1 (Eurocode 2) and the following National Annexes:
DIN EN 1992-1-1/NA/A1:2015-12 (Germany)
ÖNORM B 1992-1-1:2018-01 (Austria)
Belgium NBN EN 1992-1-1 ANB:2010 for design at normal temperature, and NBN EN 1992-1-2 ANB:2010 for fire resistance design (Belgium)
BDS EN 1992-1-1:2005/NA:2011 (Bulgaria)
EN 1992-1-1 DK NA:2013 (Denmark)
NF EN 1992-1-1/NA:2016-03 (France)
SFS EN 1992-1-1/NA:2007-10 (Finland)
UNI EN 1992-1-1/NA:2007-07 (Italy)
LVS EN 1992-1-1:2005/NA:2014 (Latvia)
LST EN 1992-1-1:2005/NA:2011 (Lithuania)
MS EN 1992-1-1:2010 (Malaysia)
NEN-EN 1992-1-1+C2:2011/NB:2016 (Netherlands)
NS EN 1992-1 -1:2004-NA:2008 (Norway)
PN EN 1992-1-1/NA:2010 (Poland)
NP EN 1992-1-1/NA:2010-02 (Portugal)
SR EN 1992-1-1:2004/NA:2008 (Romania)
SS EN 1992-1-1/NA:2008 (Sweden)
SS EN 1992-1-1/NA:2008-06 (Singapore)
STN EN 1992-1-1/NA:2008-06 (Slovakia)
SIST EN 1992-1-1:2005/A101:2006 (Slovenia)
UNE EN 1992-1-1/NA:2013 (Spain)
CSN EN 1992-1-1/NA:2016-05 (Czech Republic)
BS EN 1992-1-1:2004/NA:2005 (United Kingdom)
CPM 1992-1-1:2009 (Belarus)
CYS EN 1992-1-1:2004/NA:2009 (Cyprus)
In addition to the National Annexes (NA) listed above, you can also define a specific NA, applying user‑defined limit values and parameters.
Optional presetting of partial safety factors, reduction factors, neutral axis depth limitation, material properties, and concrete cover
Determination of longitudinal, shear, and torsional reinforcement
Design of tapered members
Cross‑section optimization
Representation of minimum and compression reinforcement
Determination of editable reinforcement proposal
Crack width analysis with optional increase of the required reinforcement in order to keep the defined limit values of the crack width analysis
Nonlinear calculation with consideration of cracked cross‑sections (for EN 1992‑1‑1:2004 and DIN 1045‑1:2008)
Considering tension stiffening
Considering creep and shrinkage
Deformations in cracked sections (state II)
Graphical representation of all result diagrams
Fire resistance design according to the simplified method (zone method) according to EN 1992‑1‑2 for rectangular and circular cross‑sections. Thus, fire resistance design of brackets is possible as well.
After the calculation, the module shows clearly arranged tables listing the required reinforcement and the results of the serviceability limit state design. All intermediate values are included in a comprehensible manner. In addition to the tables, current stresses and strains in a cross‑section are represented graphically.
The reinforcement proposals of the longitudinal and the shear reinforcement, including sketches, are documented in accordance with current practice. It is possible to edit the reinforcement proposal and to adjust, for example, the number of members and the anchorage. The modifications will be updated automatically.
A concrete cross‑section, including reinforcement, can be visualized in a 3D rendering. This way, the program provides an optimal documentation option to create reinforcement drawings, including steel schedule.
Crack width analyzes are performed using the selected reinforcement of internal forces in the serviceability limit state. The result output covers steel stresses, the minimum reinforcement, limit diameters, and the maximum bar spacing, as well as crack spacing and the maximum crack widths.
As a result of the nonlinear calculation, there are the ultimate limit states of the cross‑section with defined reinforcement (determined linear elastically) as well as effective deflections of the member considering stiffness in cracked state.
After opening the program, you can define the standard and method according to which the design is performed. The ultimate and serviceability limit states can be designed according to the linear and nonlinear calculation methods. Load cases, load combinations or result combinations are then assigned to different calculation types. In other input windows, you can define materials and cross‑sections. In addition, it is possible to assign parameters for creep and shrinkage. Creep and shrinkage coefficients are directly adjusted, depending on the age of the concrete.
Support geometry is determined by means of design‑relevant data such as support widths and types (direct, monolithic, end, or intermediate support) and redistribution of moments as well as shear force and moment reduction. CONCRETE recognizes the support types from the RSTAB model automatically.
A segmented window includes the specific reinforcement data such as diameters, the concrete cover and curtailment type of reinforcements, number of layers, cutting ability of links, and the anchorage type. In the case of the fire resistance design, it is necessary to define the fire resistance class, the fire‑related material properties, and the cross-section side exposed to fire. Members and sets of members can be summarized in special 'reinforcement groups', each with different design parameters.
You can adjust the limit value of the maximum crack width in the case of crack width analysis. The geometry of tapers is to be determined additionally for the reinforcement.
When determining internal forces, you can choose between calculation method 1 (uncracked over entire beam length) and calculation method 2 (crack formation over internal columns).
In both cases, it is possible to consider a constant effective width of the concrete slab over the entire span according to ENV 1994-1-1, 4.2.2.1 (1) and a redistribution of the moments. Internal forces for the design of shear connectors can only be determined by the elastic calculation of internal forces using the RSTAB analysis core (no RSTAB license is required).
The calculation performs fully automatic determination of the effective cross-section properties at the respective points of time, considering creep and shrinkage. In the RSTAB user interface, the structural models are created as a member structure, including all boundary conditions and loading. This way, reliable calculation of the internal forces with the effective cross-section properties is ensured.
For the design according to Eurocode 3, the following National Annexes are available:
DIN EN 1993-1-5/NA:2010-12 (Germany)
SFS EN 1993-1-5/NA:2006 (Finland)
NBN EN 1993-1-5/NA:2011-03 (Belgium)
UNI EN 1993-1-5/NA:2011-02 (Italy)
NEN EN 1993-1-5/NA:2011-04 (Netherlands)
NS EN 1993-1-5/NA:2009-06 (Norway)
CSN EN 1993-1-5/NA:2008-07 (Czech Republic)
CYS EN 1993-1-5/NA:2009-03 (Cyprus)
In addition to the National Annexes listed above, you can also define a specific NA, applying user-defined limit values and parameters.
Import of all relevant internal forces from RFEM/RSTAB by selecting numbers of members and buckling panels with determination of governing boundary stresses
Summary of stresses in load cases with determination of governing load
Different materials for stiffener and plate possible
Import of stiffeners from an extensive library (flat plate and bulb flat steel, angle, T-section, channel, and trapezoidal sheeting)
Determination of effective widths according to EN 1993-1-5 (Table 4.1 or 4.2) or DIN 18800, Part 3, Eq. (4)
Optional calculation of critical buckling stresses according to analytical formulas of annexes A.1, A.2, and A.3 of EC 3, or by means of FEA calculation
Designs (stress, deformation, torsional buckling) of longitudinal and transverse stiffeners
Optional consideration of buckling effects according to DIN 18800, Part 3, Eq. (13)
Photo-realistic representation (3D rendering) of buckling panel, including stiffeners, stress conditions, and buckling modes with animation
Documentation of all input data and results in a verifiable printout report
Results are displayed in result tables sorted by required designs. Clear arrangement of the results allows for easy orientation and evaluation.
Ultimate Limit State Design:
Bending and shear force resistance with interaction
Partial shear connecting of ductile and non-ductile connecting elements
Determination of required shear connectors and their distribution
Design of longitudinal shear force resistance
Design of connection with shear connectors and of connector perimeter
Results of governing support reactions for construction and composite stage, including loads of construction supports
Lateral-torsional buckling analysis (for continuous beams and cantilevered girders)
Check of cross-section classes as well as of plastic and elastic cross-section properties
Serviceability limit state design:
Deflection Analysis
Deformations and initial pre-cambering determined with ideal cross-section properties from creep and shrinkage
Analysis of natural frequencies
Crack width analysis
Determination of support forces
All data are documented in a clearly arranged printout report, including graphics. In case of any modification, the printout report is updated automatically. COMPOSITE-BEAM is a stand-alone program and does not require the RSTAB license.
In RX-TIMBER Glued-Laminated Beam, the following calculation settings are available:
Design of ULS, SLS, and/or fire resistance
Selection of designs to be performed
Determination of displaying support forces and deformations
Adjusting the recommended limit values for the deformation analyses
Definition of parameters for the fire resistance design performed according to the simplified method (optionally for F 30‑B, F 60‑B, F 90‑B, and user‑defined)
Determination of tilting moment for pinned support
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.
First, it is necessary to select a tower type and the relevant materials and cross-sections. The tower geometry is defined by individual tower segments. Slopes can be defined via widths or relatively by geometry modification.
After entering the tower legs, you can specify various stiffening of the lattice tower. It is possible to enter detailed specifications of horizontal girts, inner bracing, and vertical bracing of a tower with unequal sides. An extensive library including parametrized bracing types facilitates the input.
In addition, there is an interactive graphic in all input windows.
Initially, it is necessary to define material data, panel dimensions, and boundary conditions (hinged, built-in, unsupported, hinged-elastic). It is possible to transfer the data from RFEM/RSTAB. Then, boundary stresses can be either defined for each load case manually or imported from RFEM/RSTAB.
Stiffeners are modeled as spatially effective surface elements that are eccentrically connected to the plate. Therefore, it is not necessary to consider the stiffener eccentricities by effective widths. The bending, shear, strain, and St. Venant stiffness of stiffeners as well as the Bredt stiffness of closed stiffeners is determined automatically in a 3D model.