When generating shear walls and deep beams, you can assign not only surfaces and cells, but also members.
You can neglect openings with a certain area in the building model calculation. This function can be activated in the global settings of the building stories. A warning message appears saying that the openings have been neglected.
In the Geotechnical Analysis add-on, the Hoek-Brown material model is available. The model shows linear-elastic ideal-plastic material behavior. Its nonlinear strength criterion is the most common failure criterion for stone and rocks.
You can enter the material parameters using
- Rock parameters directly, or alternatively via
- GSI classification.
Detailed information about this material model and the definition of the input in RFEM can be found in the respective chapter Hoek-Brown Model of the online manual for the Geotechnical Analysis add-on.
The building story generator in the Building Model add-on allows you to automatically create building stories, depending on the topology of the model.
- Realistic representation of interaction between a building and soil
- Realistic representation of the influences of the foundation components on each other
- Extensible library of soil properties
- Consideration of several soil samples (probes) at different locations, even outside the building
- Determination of settlements and stress diagrams as well as their graphical and tabular display
For a response spectrum analysis of building models, you can display the sensitivity coefficients for the horizontal directions by story.
These key figures allow you to interpret the sensitivity to stability effects.
You can display the results as usual via the Results navigator. Furthermore, the dialog box of the add-on shows you the information about the individual floors. Thus, you always have a good overview.
You have two options for a building model. You can create it when you start modeling the structure, or activate it afterwards. In the building model, you can then directly define the stories and manipulate them.
When manipulating the stories, you can choose whether to modify or retain the included structural elements using various options.
RFEM does some of the work for you. For example, it automatically generates result sections, so you don't need to perform a lot of calculations.
Shear walls and deep beams of a building model are available as independent objects in the design add-ons. This allows for faster filtering of the objects in results, as well as better documentation in the printout report.
Enter and model a soil solid directly in RFEM. You can combine the soil material models with all common RFEM add-ons.
This allows you to easily analyze the entire models with a complete representation of the soil-structure interaction.
All parameters required for the calculation are automatically determined from the material data that you have entered. The program then generates the stress-strain curves for each FE element.
The modal relevance factor (MRF) can help you to assess to which extent specific elements participate in a specific mode shape. The calculation is based on the relative elastic deformation energy of each individual member.
The MRF can be used to distinguish between local and global mode shapes. If multiple individual members show significant MRF (for example, > 20%), the instability of the entire structure or a substructure is very likely. On the other hand, if the sum of all MRFs for an eigenmode is around 100%, a local stability phenomenon (for example, buckling of a single bar) can be expected.
Furthermore, the MRF can be used to determine critical loads and equivalent buckling lengths of certain members (for example, for stability design). Mode shapes for which a specific member has small MRF values (for example, < 20%) can be neglected in this context.
The MRF is displayed by mode shape in the result table under Stability Analysis → Results by Members → Effective Lengths and Critical Loads.
- Consideration and display of story masses
- Listing of structural elements and their information
- Automated creation of result sections on shear walls
- Output of section resultants in global direction for determining shear forces
- Optional definition of rigid diaphragm by story (story modeling)
- Stiffness type Floor Slab - Rigid Diaphragm
- Defining floor sets,
- for example, calculation of slabs as a 2D position within the 3D model
- Shear walls: Automatic definition of result members with any cross-section
- Design of rectangular cross-sections using the Concrete Design add-on
- Definition of deep beams
- Design with the Concrete Design add-on
- Tabular output of story actions, interstory drift, and center points of mass and stiffness, as well as the forces in shear walls
- Separate result display of the floor and stiffening design
- Optional neglecting of openings of a certain size
The Dlubal structural analysis software does a lot of work for you. The input parameters, which are relevant for the selected standards, are suggested by the program in accordance with the rules. Furthermore, you can enter response spectra manually.
Load cases of the type Response Spectrum Analysis define the direction in which response spectra act and which eigenvalues of the structure are relevant for the analysis. In the spectral analysis settings, you can define details for the combination rules, damping (if applicable), and zero-period acceleration (ZPA).
- Calculation of models consisting of member, shell, and solid elements
- Nonlinear stability analysis
- Optional consideration of axial forces from initial prestress
- Four equation solvers for an efficient calculation of various structural models
- Optional consideration of stiffness modifications in RFEM/RSTAB
- Determination of a stability mode greater than the user-defined load increment factor (Shift method)
- Optional determination of the mode shapes of unstable models (to identify the cause of instability)
- Visualization of the stability mode
- Basis for determining imperfection
If there is a load case or load combination in the program, the stability calculation is activated. You can define another load case in order to consider initial prestress, for example.
For this, you need to specify whether to perform a linear or nonlinear analysis. Depending on the case of application, you can select a direct calculation method, such as the Lanczos method or the ICG iteration method. Members not integrated in surfaces are usually displayed as member elements with two FE nodes. With such elements, the program cannot determine the local buckling of single members. That's why you have the option to divide members automatically.
Compared to the RF-/DYNAM Pro - Equivalent Loads add-on module (RFEM 5 / RSTAB 8), the following new features have been added to the Response Spectrum Analysis add-on for RFEM 6 / RSTAB 9:
- Response spectra of numerous standards (EN 1998, DIN 4149, IBC 2018, and so on)
- User-defined response spectra or those generated from accelerograms
- Direction-relative response spectrum approach
- Results are stored centrally in a load case with underlying levels to ensure clarity
- Accidental torsional actions can be taken into account automatically
- Automatic combinations of seismic loads with the other load cases for use in an accidental design situation
Entering soil layers for soil samples is performed in a clearly arranged dialog box. A corresponding graphical representation supports clarity and makes checking the input user-friendly.
An extensible database facilitates the selection of soil material properties. The Mohr-Coulomb model as well as a nonlinear model with stress and strain dependent stiffness are available for a realistic modeling of the soil material behavior.
You can define any number of soil samples and layers. The soil is generated from all entered samples using 3D solids. Assignment to the structure is carried out using coordinates.
The soil body is calculated according to the nonlinear iterative method. The calculated stresses and settlements are displayed graphically and in tables.
The load cases of the type Response Spectrum Analysis contain the generated equivalent loads. First, the modal contributions have to be superimposed with the SRSS or CQC rule. In this case, you can use the signed results based on the dominant mode shape.
Afterwards, the directional components of earthquake actions are combined with the SRSS or the 100% / 30% rule.
Did you know? You can enter the soil layers that you have obtained from the subsoil expertises done in the locations into the program in the form of soil samples. Assign the explored soil materials, including their material properties, to the layers.
For the definition of the samples, you can enter the data in tables as well as in the respective editing dialog box. Furthermore, you can also specify the groundwater level in the soil samples.
Are you afraid that your project will end in the digital tower of Babel? The Building Model add-on for RFEM supports you in your work on a construction project with several stories. It allows you to define a building by means of stories at specified elevations. You can adjust the stories in many ways afterwards and also select the story slab stiffness. Information about the stories and the entire model (center of gravity, center of rigidity) is displayed for you in tables and graphics.
Several modeling tools are available for elements in building models:
- Vertical line
- Column
- Wall
- Beam
- Rectangular floor
- Polygonal floor
- Rectangular floor opening
- Polygonal floor opening
This feature allows you to define the element on the ground plane (for example, with a background layer) with the associated multiple element creation in space.
As the first results, the program presents you with the critical load factors. You can then perform an evaluation of stability risks. For member models, the resulting effective lengths and critical loads of the members are displayed to you in tables.
Use the next result window to check the normalized eigenvalues sorted by node, member, and surface. The eigenvalue graphic allows you to evaluate the buckling behavior. This makes it easier for you to take countermeasures.
You already know that it is possible to model and analyze a soil and a structure in the entire model. As a result, you have explicitly taken into account the soil-structure interaction. By modifying a component, you achieve the immediate correct consideration in the analysis as well as in the results for the entire system of the soil and structure.
A graphical and tabular output of the results for deformations, stresses, and strains helps you when determining the soil solids. To achieve this, use the special filter criteria for targeted selection of results.
The program doesn't leave you alone with the results. If you want to graphically evaluate the results in the soil solids, you can use the guide objects. For example, you can define clipping planes. This allows you to view the corresponding results in any plane of the soil solid.
And not just that. The utilization of result sections and clipping boxes facilitates the precise graphical analysis of the soil solid.
Did you know that Equivalent static loads are generated separately for each relevant eigenvalue and excitation direction. These loads are saved in a load case of the Response Spectrum Analysis type and RFEM/RSTAB performs a linear static analysis.
Using the "Load Transfer Only" story type, you can consider slabs without stiffness effect in and out of the plane in the Building Model add-on. This element type collects the loads on the slab and transfers them to the supporting elements of a 3D model. Thus, you can simulate secondary components, such as grillage and similar load distribution elements, without any further effect in the 3D model.
Compared to the RF‑/STABILITY (RFEM 5) and RSBUCK (RSTAB 8) add-on modules, the following new features have been added to the Structure Stability add-on for RFEM 6 / RSTAB 9:
- Activation as a property of a load case or a load combination
- Automated activation of the stability calculation via combination wizards for several load situations in one step
- Incremental load increase with user-defined termination criteria
- Modification of the mode shape normalization without recalculation
- Result tables with filter option
Your data are always documented in a multilingual printout report. You can adjust the content at any time and save it as a template. You can also add graphics, texts, MathML formulas, and PDF documents to your report with just a few clicks.
The soil solids that you want to analyze are summarized in soil massifs.
Use the soil samples as a basis for a definition of the respective soil massif. This way, the program allows for user-friendly generation of the massif, including the automatic determination of the layer interfaces from the sample data, as well as the groundwater level and the boundary surface supports.
Soil massifs provide you with the option to specify a target FE mesh size independently of the global setting for the rest of the structure. You can thus consider the various requirements of the building and soil in the entire model.
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).
- ICG Iteration Method (Incomplete Conjugate Gradient [RFEM])
- 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.