In RFEM, the oriented strand board (OSB) material is available for the USA and Canada. The material parameters are taken from the "Panel Design Specification manual".
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.
- 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 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.
Using the "Beam Panel" thickness type, you can model timber panel elements in 3D space. You just specify the surface geometry and the timber panel elements are generated using an internal member-surface construct, including the simulation of the connection flexibility. The Beam Panel thickness type is defined using the Multilayer Surfaces add-on.
A "beam panel" provides you with the following advantages:
- Single-sided and double-sided sheathing is possible
- Automatic calculation of a semi-rigid coupling
- Boarded sheathing
- Stapled sheathing
- User-defined sheathing
- Representation as a complete geometric 3D object (frame, crosstie, column, sheeting, staples), including eccentricity
- Considering openings via surface cells
- Design of the structural elements utilizing the Timber Design add-on
- Independent of material (for example, drywall with cold-formed sections and gypsum fibreboards as the sheathing)
The building model is calculated in two phases:
- Global 3D calculation of the global model, where the slabs are modeled as a rigid plane (diaphragm) or as a bending plate
- Local 2D calculation of the individual floors
After the calculation, the results of the columns and walls from the 3D calculation and the results of the slabs from the 2D calculation are combined in a single model. This means that there is no need to switch between the 3D model and the individual 2D models of the slabs. The user only works with one model, saves valuable time, and avoids possible errors in the manual data exchange between the 3D model and the individual 2D ceiling models.
The vertical surfaces in the model can be divided into shear walls and opening lintels. The program automatically generates internal result members from these wall objects, so they can be designed as members according to any standard in the Concrete Design add-on.
For calculation diagrams, you can use the "2D | Hinge" diagram type. These hinge diagrams show the hinge response of load situations for nonlinear hinges.
For calculations with several load situations, such as the case with the pushover analysis and time history analysis, you can evaluate the hinge condition in each load step.
The Time History Analysis add-on provides you with accelerograms for the calculation. This extension allows for dynamic structural analysis of the acceleration-time diagrams.
There is an extensive library of earthquake records available for you, but you can also enter or import your own diagrams. The time history analysis is performed using the modal analysis or the linear implicit Newmark analysis.
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.
The "2D | Story" calculation diagram type is used to create result diagrams via the building axis. This allows you to easily analyze the behavior of the entire building under static and dynamic effects.
You can use this diagram type, for example, to visualize the seismic force over the building height.
Among others, the following cross-laminated timber manufacturers are available in the layer structure library:
- Binderholz (USA)
- KLH (USA, CAN)
- Kalesnikoff (USA, CAN)
- Nordic Structures (USA, CAN)
- Mercer Mass Timber
- SmartLam
- Sterling Structural
- Superstructures listed in Lignatec Edition 32 "Cross-Laminated Timber of Swiss Production"
By importing a structure from the layer structure library, all relevant parameters are adopted automatically. The library is continually updated.
- Analysis of time diagrams and accelerograms (acceleration-time diagrams exciting the supports of a structure)
- Combination of user-defined time diagrams with nodal, member, and surface loads, as well as free and generated loads
- Combination of several independent excitation functions
- Linear implicit Newmark analysis or modal analysis in time history
- Structural damping using Raleigh damping coefficients or Lehr's damping value
- Graphical display of results in calculation diagrams
- Result display in individual time steps or as an envelope during the entire time period
- Extensive library of seismic events (accelerograms)
It is necessary to enter the required force-time diagrams. They can be combined in load cases or load combinations of the type Time History Analysis | Time Diagrams with the loading in order to define where and in which direction the force-time diagrams act.
The second option is to enter acceleration-time diagrams, which can be used in the load cases of the Time History Analysis | Accelerogram type.
All calculation parameters are specified in the time history analysis settings. These include, for example, the type of analysis method and the maximum calculation time.
The time history analysis is performed with the modal analysis or the linear implicit Newmark analysis. The time history analysis in this add-on is limited to linear structural systems. Although the modal analysis represents a fast algorithm, it is necessary to use a certain number of eigenvalues to ensure the required accuracy of results.
The implicit Newmark analysis is a very precise method, independent of the number of eigenvalues used, but requires sufficient small time steps for the calculation.
As soon as the program has completed the calculation, the summary of the results is listed. All result windows are integrated in the main program RFEM/RSTAB. You will find all the results arranged in tables; they can be displayed for each individual time step or as an envelope, and you also have the option of displaying the results graphically as well as animating them.
The results from the time history analysis can be displayed in the calculation diagrams. All the results are shown as a function of time. You can export the numeric values to MS Excel.
All result tables and graphics are part of the RFEM/RSTAB printout report. In this way, you can ensure clearly arranged documentation. You can also export the tables to MS Excel.
- Outsource calculation on a computing server in the cloud
- Option to select different powerful computing servers
- Clearly arranged display of all calculation tasks in the Extranet
- Calculated files are available for download for two months
- Virtually unlimited computing capacity using cloud technology
The model and loads are entered as usual in the RFEM interface.
You can start the cloud calculation by selecting an entry in the Calculate menu. Then, select the virtual machine suitable for the task and start the calculation.
After the start, the image is used to create a virtual machine on which the computing server is started. This takes over the calculation of your file.
You can monitor the processing of calculation tasks in the Extranet.
After completing the calculation, you will receive an email with a link to download the calculated file. Large files are compressed into a ZIP archive. Smaller files can be downloaded directly.
As an alternative, there is a link to the calculated file in the Extranet.
The downloaded file is a common RFEM file and can be used for further processing as usual.
In the "Steel Joints" add-on, you can consider preloaded bolts in all components during the calculation. You can easily activate the preloading using the check box in the bolt parameters, and it has an impact on the stress-strain analysis as well as the stiffness analysis.
Preloaded bolts are special bolts used in steel structures to generate a high clamping force between the connected structural components. This clamping force causes friction between the structural components, which allows for the transfer of forces.
Functionality
Preloaded bolts are tightened with a certain torque, causing them to stretch and generate a tensile force. This tensile force is transferred to the connected components and leads to a high clamping force. The clamping force prevents the connection from loosening and ensures safe force transmission.
Advantages
- High load-bearing capacity: Preloaded bolts can transfer large forces.
- Low deformation: They minimize the deformation of the connection.
- Fatigue strength: They are resistant to fatigue.
- Easy assembly: They are relatively easy to assemble and disassemble.
Analysis and Design
The calculation of preloaded bolts is performed in RFEM using the FE analysis model generated by the "Steel Joints" add-on. It takes into account the clamping force, friction between structural components, shear strength of bolts, and load-bearing capacity of the structural components. The design is carried out according to DIN EN 1993‑1‑8 (Eurocode 3) or the US standard ANSI/AISC 360‑16. You can save the created analysis model, including the results, and use it as an independent RFEM model.
When using multiple identical blocks in a model, you can assign a reference block to the selected blocks.
If you then change parameters such as geometry, material, and cross-section of the reference block, these are automatically adopted for the "child blocks".
Go to Explanatory Video