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.
Have you activated the Building Model add-on? Very good! This allows you to display the center of rigidity in tabular and graphical form. Use it for your dynamic analysis, for example.
As you've already learned, the results of a Modal Analysis load case are displayed in the program after a successful calculation. You can thus immediately see the first mode shape graphically or as an animation. You can also easily adjust the representation of the mode shape standardization. Do that directly in the Results navigator, where you have one of four options for the visualization of the mode shapes available for the selection:
- Scaling the value of the mode shape vector uj to 1 (considers the translation components only)
- Selecting the maximum translational component of the eigenvector and setting it to 1
- Considering the entire eigenvector (including the rotation components), selecting the maximum, and setting it to 1
- Setting the modal mass mi for each mode shape to 1 kg
You can find a detailed explanation of the mode shape standardization in the OnlineManual here.
RFEM allows you to use a special line hinge to model the special properties of the connection between the reinforced concrete slab and masonry wall. This limits the transferable forces of the connection depending on the specified geometry. You guess right: This means that the material cannot be overloaded.
The program develops interaction diagrams that are applied automatically. They represent the various geometric situations and you can use them to determine the correct stiffness.
Is the calculation finished? The results of the modal analysis are then available both graphically and in tables. Display the result tables for the load case or the load cases of the modal analysis. Thus, you can see the eigenvalues, angular frequencies, natural frequencies, and natural periods of the structure at first glance. The effective modal masses, modal mass factors, and participation factors are also clearly displayed.
Is your goal to determine the number of mode shapes? The program offers you two methods for this. On the one hand, you can manually define the number of the smallest mode shapes to be calculated. In this case, the number of available mode shapes depends on the degrees of freedom (that is, the number of free mass points multiplied by the number of directions in which the masses act). However, it is limited to 9999. On the other hand, you can set the maximum natural frequency the way that the program determined the mode shapes automatically until reaching the natural frequency set.
Did you know that To calculate masonry structures, a nonlinear material model has been implemented in RFEM. It is based on the approach of Lourenco, a composite yield surface according to Rankine and Hill. This model allows you to describe and model the structural behavior of masonry and the different failure mechanisms.
The limit parameters were selected in such a way that the design curves used correspond to a normative design curve.
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.
The Concrete Design add-on allows you to perform the seismic design of reinforced concrete members according to EC 8. This includes, among other things, the following functionalities:
- Seismic design configurations
- Differentiation of the ductility classes DCL, DCM, DCH
- Option to transfer the behavior factor from a dynamic analysis
- Check of the limit value for the behavior factor
- Capacity design checks of "Strong column - weak beam"
- Detailing and particular rules for curvature ductility factor
- Detailing and particular rules for local ductility
A library for cross-laminated timber panels is implemented in RFEM, from which you can import the manufacturer's layer structures (for example, Binderholz, KLH, Piveteaubois, Södra, Züblin Timber, Schilliger, Stora Enso). In addition to the layer thicknesses and materials, there is also the information about stiffness reductions and the narrow side bonding.
Go to Explanatory VideoThe calculation of masonry is carried out in compliance with the nonlinear-plastic material law. If the load at any point is higher than the possible load to be resisted, redistribution takes place within the system. This have the simple purpose of restoring the equilibrium of forces. With the successful completion of the calculation, the stability analysis is provided.
Do you know exactly how the form-finding is performed? First, the form-finding process of the load cases with the load case category "Prestress" shifts the initial mesh geometry to an optimally balanced position by means of iterative calculation loops. For this task, the program uses the Updated Reference Strategy (URS) method by Prof. Bletzinger and Prof. Ramm. This technology is characterized by equilibrium shapes that, after the calculation, comply almost exactly with the initially specified form-finding boundary conditions (sag, force, and prestress).
In addition to the pure description of the expected forces or sags on the elements to be formed, the integral approach of the URS also enables a consideration of regular forces. In the overall process, this allows, for example, for a description of the self-weight or a pneumatic pressure by means of corresponding element loads.
All these options give the calculation kernel the potential to calculate anticlastic and synclastic forms that are in an equilibrium of forces for planar or rotationally symmetric geometries. In order to be able to realistically implement both types individually or together in one environment, the calculation provide you with two ways to describe the form-finding force vectors:
- Tension method - description of the form-finding force vectors in space for planar geometries
- Projection method - description of the form-finding force vectors on a projection plane with fixation of the horizontal position for conical geometries
Have you already discovered the tabular and graphical output of masses in mesh points? That's right, this is also part of the modal analysis results in RFEM 6. This way, you can check the imported masses that depend on various settings of the modal analysis. They can be displayed in the Masses in Mesh Points tab of the Results table. The table provides you with an overview of the following results: Mass - Translational Direction (mX, mY, mZ), Mass - Rotational Direction (mφX, mφY, mφZ), and the Sum of Masses. Would it be best for you to have a graphical evaluation as quickly as possible? Then you can also graphically display the masses in mesh points.
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.
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.
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- General
- Optimization & Cost / CO2 Emission Estimation for RFEM 6
- Optimization & Cost / CO2 Emission Estimation for RSTAB 9
You can be sure that costs are an important factor in the structural planning of any project. It is also essential to adhere to the provisions on emissions estimation. The two-part add-on Optimization & Costs/CO2 Emission Estimation makes it easier for you to find your way through the jungle of standards and options. It uses the artificial intelligence technology (AI) of the particle swarm optimization (PSO) to find the right parameters for parameterized models and blocks that guarantee the compliance with the usual optimization criteria. This add-on also estimates the model costs or CO2 emissions by specifying unit costs or emissions per material definition for the structural model. With this add-on, you are on the safe side.
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.
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.
Compared to the RF-FORM-FINDING add-on module (RFEM 5), the following new features have been added to the Form-Finding add-on for RFEM 6:
- Specification of all form-finding load boundary conditions in one load case
- Storage of form-finding results as initial state for further model analysis
- Automatic assignment of the form-finding initial state via combination wizards to all load situations of a design situation
- Additional form-finding geometry boundary conditions for members (unstressed length, maximum vertical sag, low-point vertical sag)
- Additional form-finding load boundary conditions for members (maximum force in member, minimum force in member, horizontal tension component, tension at i-end, tension at j-end, minimum tension at i-end, minimum tension at j-end)
- Material types "Fabric" and "Foil" in material library
- Parallel form-findings in one model
- Simulation of sequentially building form-finding states in connection with the Construction Stages Analysis (CSA) add-on
Once you activate the Form-Finding add-on in the Base Data, a form-finding effect is assigned to the load cases with the load case category "Prestress" in conjunction with the form-finding loads from the member, surface, and solid load catalog. This is a prestress load case. It thus mutates into a form-finding analysis for the entire model with all member, surface, and solid elements defined in it. You reach the form-finding of the relevant member and membrane elements amid the overall model by using special form-finding loads and regular load definitions. These form-finding loads describe the expected state of deformation or force after the form-finding in the elements. The regular loads describe the external loading of the entire system.