In RFEM, areas can be defined where the internal forces in surfaces are not displayed with the real distribution from FE calculation, but as mean values. You can use various settings for averaging the internal forces. There are three possible application areas of the "Average Region" function.
You can now also create concentrated member and line loads in RFEM and RSTAB. This is an extension of the original member/line load function. From now on, you can create several concentrated loads with uniform or user-defined load distribution on a member or a line.
In the case of a large amount of reinforcement, it might be useful to grade the longitudinal reinforcement of a beam, which means: curtailment. The grading corresponds to the tensile force distribution. Using RF-CONCRETE Members and CONCRETE, you can specify the curtailment of the reinforcement, which is considered in the automatically proposed reinforcement for the longitudinal reinforcement. When determining this reinforcement proposal, it is necessary to ensure that the envelope of the acting tensile force can be absorbed.
"Distribution of load" represents a load actually applied to the system of FE mesh points or FE surfaces. The FE mesh size plays an important role in the loading in the case of line loads and free loads in particular.
In order to detect the governing internal forces of a plate, a checkerboard loading is commonly used. Since it is not necessary to divide the surface into individual load segments, loading is usually carried out by means of free rectangular loads. In the case of many loads, the normal load display can become somewhat confusing.
When a concrete slab is set upon the top flange, its effect is like a lateral support (composite construction), preventing problems of torsional buckling stability. If there is a negative distribution of the bending moment, the bottom flange is subjected to compression and the top flange is under tension. If the lateral support given by the stiffness of the web is insufficient, the angle between the bottom flange and the web intersection line is variable in this case so that there is a possibility of distortional buckling for the bottom flange.
Performing serviceability limit state design also includes taking into account the allowable deformation. Calculating the deformation of reinforced concrete components depends on whether or not the observed cross-section cracks under the applied loading. The governing control parameter in RF-CONCRETE Deflect is the distribution coefficient ζ.
RF‑CONCRETE Surfaces performs the ultimate and the serviceability limit state design of slabs, plates, folded plates, and shells. In RFEM 5, the reinforcement resulting from this design can be displayed graphically on the surfaces of the structure using isolines. For the reinforcement design, it may be useful to export the results as isoline distribution in a DXF file in order to open them in a CAD application as background layers.
Designing vertical insulating glass requires assigning different loads on the individual layers of the entire glass unit. This occurs, for example, with simultaneous actions from wind loads and fall protection.
RWIND 2 and RFEM 6 can now be used to calculate wind loads from experimentally measured wind pressures on surfaces. Basically, two interpolation methods are available to distribute pressures measured in isolated points across the surfaces. The desired pressure distribution can be achieved using the appropriate method and parameter settings.
The German Annex to EN 1992‑1‑1, the National Addition NCI to Article 9.2.1.2 (2), recommends to dispose the tension reinforcement in the flange plate of T‑beam cross‑sections on a maximum of one width corresponding to the half of a computed effective flange width beff,i according to Expression (5,7a).
When designing column bases, high-performance anchors are often used for an anchorage. This article describes different models for a column footing and the evaluation thereof.
With the "Generate Model - Members" → "3D Cell" function, it is very easy to generate containers (shipping containers, office containers, mobile homes, and so on) with regular and irregular distribution of the cells.
When evaluating line support forces, implausible diagrams sometimes arise at first glance. In particular, for variable loads at locations that also have a nodal support, at division points and edge locations of supported lines, the results sometimes show unexpected support reactions. Using the function of the linear smooth distribution in Project Navigator – Display does not always lead to the expected result diagram.
A new direction for temperature load is available in RFEM. Now, it is also possible to apply temperature loads with radial load distribution on a structure. The load is defined using an outer and an inner node, and an axis around which the radial load is applied.
In RFEM 6, the results for the FE mesh nodes are determined using the finite element method. For the distribution of internal forces, deformations, and stresses to be continuous, these nodal values are smoothed through an interpolation process. This article will introduce and compare the different types of smoothing that you can use for this purpose.
For the serviceability limit state design according to Section 6.6 of Eurocode EN 1997‑1, settlement has to be calculated for spread foundations. RF-/FOUNDATION Pro allows you to perform the settlement calculation for a single foundation. For this, you can chose between an elastic and a solid foundation. By defining a soil profile, it is possible to consider several soil layers under the foundation base. The results of the settlement, foundation tilting, and vertical soil contact stress distribution are displayed graphically and in tables to provide a quick and clear overview of the calculation performed. In addition to the design of the foundation settlement in RF-/FOUNDATION Pro, the structural analysis determines the representative spring constants for the support and can be exported to the structural model of RFEM or RSTAB.
When calculating a surface model, the internal forces are determined separately for each finite element. Since the element-by-element results usually represent a discontinuous distribution, RFEM performs smoothing of the internal forces that takes into account the influence of adjacent elements. The discontinuous distribution of internal forces is adjusted with this method. The result evaluation is thus clearer and easier.
Just as in the RFEM Display Navigator, you can set the distribution of internal forces in surfaces in RF‑STEEL Surfaces. Since deformations are always the result of the FEM calculation, the corresponding forces will be recalculated. This means that the internal forces on an FEM element are calculated depending on the composition (triangular or square) in three or four places. In order to obtain continuous internal forces and thus a smoothed distribution, these internal forces have to be interpolated. Interpolation is done by selecting the "Distribution of internal forces" option in the surfaces.
In the existing standard, there were no regulations for the distribution of snow loads for elevated solar thermal and photovoltaic systems on roofs. Only distribution of the loads was advised. It was only with the National Annex DIN EN 1991-1-3/NA: 2019-04 that specific regulations were made for this.
In the case of tension connections with cleats subjected to unilateral loading, the external members (side timber) are loaded by an additional bending moment due to the eccentric load distribution. However, this fact is not mentioned in EN 1995‑1‑1 and is considered in the National Annex to DIN EN 1995‑1‑1 by the reduction of the tensile strength. This reduction depends on the pull-off strength of the fasteners.
Wind direction plays a crucial role in shaping the outcomes of Computational Fluid Dynamics (CFD) simulations and the structural design of buildings and infrastructures. It is a determining factor in assessing how wind forces interact with structures, influencing the distribution of wind pressures, and consequently, the structural responses. Understanding the impact of wind direction is essential for developing designs that can withstand varying wind forces, ensuring the safety and durability of structures. Simplified, the wind direction helps in fine-tuning CFD simulations and guiding structural design principles for optimal performance and resilience against wind-induced effects.
With RF-DYNAM Pro – Forced Vibrations, you can perform a time history analysis. For example, you can analyze an explosion acting on a nearby building structure. In "Dynamik der Baukonstruktionen" by Christian Petersen, formulas for time diagrams and load distribution are described to specify an explosion. The image shows the input of such an explosion load. Free variable loads are available in RFEM that enable flexible load distributions.