In RFEM and RSTAB, you can design members with the "Laminated Veneer Lumber" material type. The following manufacturers are available:
Pollmeier (Baubuche)
Metsä (Kerto LVL)
STEICO
Stora Enso
In the ultimate configuration, you can consider strength coefficients for increasing the strengths. The coefficients reducing the strengths are automatically taken into account regardless of this. Try it now!
The pushover analysis is managed by a newly introduced analysis type in the load combinations. Here, you have access to the selection of the horizontal load distribution and direction, the selection of a constant load, the selection of the desired response spectrum for the determination of the target displacement, and the pushover analysis settings tailored to the pushover analysis.
In the pushover analysis settings, you can modify the increment of the increasing horizontal load and specify the stopping condition for the analysis. Furthermore, it is possible to easily adjust the precision for the iterative determination of the target displacement.
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RF-/STEEL EC3 automatically imports the cross-sections defined in RFEM/RSTAB. It is possible to design all thin-walled cross-sections. The program automatically selects the most efficient method according to standards.
The ultimate limit state design takes into account several loads and you can select the interaction designs available in the standard.
The classification of designed cross-sections into Classes 1 to 4 is an essential part of the analysis according to Eurocode 3. This way, you can check the limitation of the design and rotational capacity by means of the local buckling of cross-section parts. RF-/STEEL EC3 determines the c/t-ratios of the cross-section parts subjected to compression stress and performs the classification automatically.
For the stability analysis, you can specify for each member or set of members whether flexural buckling occurs in the y- and/or the z-direction. You can also define additional lateral restraints in order to represent the model close to reality. The slenderness ratio and elastic critical load are determined automatically on the basis of the boundary conditions of RF-/STEEL EC3. The elastic critical moment for lateral-torsional buckling required for the lateral-torsional buckling analysis can be determined automatically or specified manually. The load application point of transverse loads, which has an influence on the torsional resistance, can also be taken into account via the setting in the details. In addition, you can take into account rotational restraints (for example trapezoidal sheeting and purlins) and shear panels (for example trapeziodal sheeting and bracing).
In modern construction, where cross-sections are increasingly slender, the serviceability limit state is an important factor in structural analysis. RF-/STEEL EC3 assigns load cases, load combinations, and result combinations to different design situations. The respective limit deformations are preset in the National Annex and can be adjusted, if necessary. In addition, it is possible to define reference lengths and precambers for the design.
In RX-TIMBER Frame, 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
Free definition of parameters for the fire resistance design performed according to the simplified method
Increasing bending stiffnesses for flat‑ended bending strains
Separate design cases allow for a flexible analysis of specific actions as well as for individual stability analyses. You can define the design type to be performed in the Control Parameters window.
Several methods are available for the eigenvalue analysis:
Direct Methods
The direct methods (Lanczos, roots of characteristic polynomial, subspace iteration method) are suitable for small to medium-sized models. These fast methods for equation solvers benefit from a lot of the computer memory (RAM). 64-bit systems use more memory so that even bigger structural systems can be calculated quickly.
This method requires only a small amount of memory. Eigenvalues are determined one after the other. It can be used to calculate large structural systems with few eigenvalues.
The RF-STABILITY add-on module can also perform the non-linear stability analysis. Also for nonlinear structures, results close to reality are provided. The critical load factor is determined by gradually increasing the loads of the underlying load case until the instability is reached. The load increment takes into account nonlinearities such as failing members, supports and foundations, and material nonlinearities.
You can select several methods that are available for the eigenvalue analysis:
Direct Methods
The direct methods (Lanczos [RFEM], roots of characteristic polynomial [RFEM], subspace iteration method [RFEM/RSTAB], and shifted inverse iteration [RSTAB]) are suitable for small to medium-sized models. You should only use these fast solver methods if your computer has a larger amount of memory (RAM).
In contrast, this method only requires a small amount of memory. Eigenvalues are determined one after the other. It can be used to calculate large structural systems with few eigenvalues.
Use the Structure Stability add-on to perform a nonlinear stability analysis using the incremental method. This analysis delivers close-to-reality results also for nonlinear structures. The critical load factor is determined by gradually increasing the loads of the underlying load case until the instability is reached. The load increment takes into account nonlinearities such as failing members, supports and foundations, and material nonlinearities. After increasing the load, you can optionally perform a linear stability analysis on the last stable state in order to determine the stability mode.
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.