Using an example of a steel fiber-reinforced concrete slab, this article describes how the use of different integration methods and of a different number of integration points affects the calculation result.
This article will show you how to use the Combination Wizard in RFEM 6 to reduce the number of load combinations to be analyzed, thus reducing the calculation effort and increasing the calculation efficiency.
Structures in RFEM 6 can be saved as blocks and reused in other RFEM files. The advantage of dynamic blocks with respect to non-dynamic blocks is that they allow interactive modifications of the structural parameters as a result of modified input variables. One example is the possibility to add structural elements by changing only the number of bays as an input variable. This article will demonstrate the aforementioned possibility for dynamic blocks that are created by scripting.
In RFEM and RSTAB, there are various options to renumber the individual structural elements, such as nodes, lines, members, surfaces, or solids. Two options are available for renumbering: singly and automatically.
The number of National Annexes for Eurocode 2 with regard to the design of reinforced concrete cross-sections has been extended since SHAPE-MASSIVE 6.54. Therefore, the following NAs of EN 1992-1-1:2004 + AC:2010 are available:
The reinforced concrete design for fire situations is carried out according to the simplified method based on EN 1992-1-2, Clause 4.2. The "zone method" described in Annex B.2 is used: The cross-section is subdivided into a number of parallel zones of equal thickness, and their temperature-dependent compressive strength is determined. The reduced load-bearing capacity in the event of fire exposure is thus represented by a reduced structural component's cross-section with reduced strengths.
In RFEM, you can display the contact properties between two surfaces by means of contact solids. Among other things, you should ensure that both contact surfaces of a contact solid have the same integrated objects. Therefore, when modeling the contact surfaces, we recommend using the copy function in order to create the second contact surface.
In the calculation parameters, you can set the number of member divisions for result diagrams. The effect of this setting option is shown in the following images.
In many cases, it is necessary to filter the results for the display of values on surfaces so as not to show all the numbers. In displaying the reinforcement arrangement, you can, for example, hide values that are below the already used basic reinforcement.
The determined values for the influence ordinates are displayed as decimal numbers with up to six decimal places by default. This is usually sufficient for the influence lines of internal forces.
The following technical article describes the creation of a user-defined platform for use on a four-sided tower in the RF-/TOWER add-on modules. First, start with an empty model of the 3D type and define four nodes. The numbering and position of these nodes are very important here.
RFEM and RSTAB are able to cover a large number of branches in the building and construction industry with their generally usable structural frame analysis and FEM programs. Designing cable structures is thus also possible in both software solutions. Some assistance tools for modeling and design will be presented in the following text.
In a multi-modal response spectrum analysis, it is important to determine a sufficient number of eigenvalues of the structure and to consider their dynamic responses. Regulations such as EN 1998‑1 [1] and other international standards require the activation of 90% of the structural mass. This means: to determine so many eigenvalues that the sum of the effective modal mass factors is greater than 0.9.
This post describes two practical examples, based on the Eurocodes, where the reduction of combinations is reasonable. A large number of various National Annexes, as well as several material standards (EC 2 to EC 9), are not in compliance with the rules for structural design (EC 0).
The "Page and Sheet Numbering" dialog box allows you to add a prefix to page and sheet numbering. It can be an abbreviation that specifies by chapter all model data in the numbering (for example, with "MO").
Due to the structural efficiency and economic benefits, dome-shaped roofs are frequently used for storehouses or stadiums. Even if the dome has the corresponding geometrical shape, it is not easy to estimate wind loads due to the Reynolds number effect. The external pressure coefficients (cpe) depend on the Reynolds numbers and on the slenderness of the structure. EN 1991‑1‑4 [1] can help you to estimate the wind loads on a dome. Based on this, the following article explains how to define a wind load in RFEM. Wind loads of the structure shown in Image 01 can be divided as follows: Wind Load on Wall, Wind Load on Dome.
In addition to straight beams, it is sometimes necessary to calculate or design arched or circular beams in RSTAB. For this purpose, there is a special feature under "Tools" → "Generate Model – Members" → "Circle". You can easily use this tool to generate a full or pitch circle. The most important parameter here is the number of new nodes, which affects the accuracy of the results.
When modeling a structure, irregular numbering of objects may occur due to copying, dividing lines and members, and so on. Automatic renumbering allows you to restructure the numbering and thus to improve the clear arrangement. This function is applicable to nodes and members as well as for lines, surfaces, and solids in RFEM.
Using the [To Display…] button, you can specify the amount of reinforcement to be displayed in the results of the required reinforcement in Window 2.2 of RF‑CONCRETE and CONCRETE. In addition to the default setting, you can display the resulting reinforcement amount as (for example) the sum of the longitudinal and longitudinal torsion reinforcement, or the sum of the torsion and shear reinforcement. You can also reduce the number of preset results, of course.
RF-/STEEL EC3 performs the classification, cross‑section designs, serviceability limit state designs, and fire resistance designs of members. For each design, the program shows a result table with the relevant values and classification numbers, including information regarding the respective standard clause. In order to identify the conjunction of various standards easily, there is a final design equation, including all terms, at the end of the table.
From time to time, gaps may occur in the numbering of load cases when working on a model. You can use the "Renumber" → "Shift" function under "Tools" to simply shift the load cases and close the gaps.
In order to reduce the number of pages in a printout report or to obtain shorter and clearer result tables, you can use filters for the printout report tables using individual detailed settings.
You can display the results on surfaces in a graphic. It may be useful to use the values on surfaces. Depending on the requirements, you can reduce the number of values considerably or adjust them to cover the entire structure. However, it is important to display the values that represent the local extreme values. In addition, it is necessary to determine the local extremes. This can be done by right-clicking this function in the Navigator.
Moving loads can be generated easily with RF‑MOVE Surfaces. A library is available with load models as defined in Eurocode 1, Part 2. The input of step size, offsets at start and end, and the distance to a reference line make it possible for the user to generate user‑defined load models and influence the number of load cases generated. RF‑MOVE Surfaces generates load cases and, optionally, a result combination as an envelope of all results.
RF-/TOWER load was extended with force coefficients for rounded profiles of four-sided towers and square-edged profiles of three-sided towers. The force coefficients for rounded profiles are determined using the Reynolds number. Previously, you could only use the rounded profiles for four‑sided towers and the square‑edged profiles for three‑sided towers.