Piping systems are exposed to a variety of loads. One of the most decisive is internal pressure. This article will, therefore, deal with the stresses and deformations resulting from a pure internal compression load in the pipe wall or for the pipe.
In current literature, the formulas used to determine internal forces and deformations manually are usually specified without considering the shear deformation. The deformations resulting from shear force are often underestimated in timber construction in particular.
Structures are naturally three-dimensional. However, because it was impossible to perform calculations on three-dimensional models easily in the past, the structures were simplified and broken down into planar subsystems. With the increasing performance of computers and related software, it is often possible to do without these simplifications. Digital trends such as Building Information Modeling (BIM) and new options for creating realistic visualized models reinforce this trend. But do 3D models really offer an advantage, or are we just following a trend? The following text presents some arguments for working in 3D models.
The following article describes the design of a single-span beam subjected to bending and compression, which is performed according to EN 1993‑1‑1 in the RF-/STEEL EC3 add-on module. Since the beam is modeled with a tapered cross-section and thus it is not a uniform structural component, the design must be performed either according to General Method in compliance with Sect. 6.3.4 of EN 1993‑1‑1, or according to the second-order analysis. Both options will be explained and compared, and for the calculation according to the second-order analysis, there is an additional design format using Partial Internal Forces Method (PIFM) available. Therefore, the design is divided into three steps: design according to Sect. 6.3.4 of EN 1993‑1‑1 (General Method), design according to the second‑order analysis, elastic (warping torsion analysis), design according to the second‑order analysis, plastic (warping torsion analysis and Partial Internal Forces Method).
In the BIM workflow, IFC files are frequently used as the basis for data exchange between CAD and structural engineering software. However, there is a fundamental problem with this approach. This article explains various types of IFC files and provides an overview of the import and export options in Dlubal Software programs.
The story drift of a building provides valuable information about its structural behavior under seismic loads. These could cause large horizontal deformations and even instabilities. Some standards, therefore, call for a check of the story drift in its center of gravity. It indicates, for example, if a second-order analysis (P-Δ effect) is necessary.
The elastic deformations of a structural component due to a load are based on Hooke's law, which describes a linear stress-strain relation. They are reversible: After the relief, the component returns to its original shape. However, plastic deformations lead to irreversible deformations. The plastic strains are usually considerably larger than the elastic deformations. For plastic stresses of ductile materials such as steel, yielding effects occur where the increase in deformation is accompanied by hardening. They lead to permanent deformations - and in extreme cases to the destruction of the structural component.
The RFEM/RSTAB printout report includes a text block function. This feature allows you to create user‑defined text blocks with formatting and heading and add them to the printout report.
Building Information Modeling describes what is possibly one of the most important current topics in the entire construction software industry. However, the process is not that new, and it is a well-known fact that the total costs of a project can be positively influenced by good planning in the initial stage.
In EN 1993-1-1, the General Method was introduced as a design format for stability analyses that can be applied to planar systems with arbitrary boundary conditions and variable structural height. The design checks can be performed for loading in the main load-bearing plane and simultaneous compression. The stability cases of lateral-torsional buckling and flexural buckling are analyzed from the main supporting plane; that is, about the weak component axis. Therefore, the issue often arises as to how to design, in this context, flexural buckling in the main load-bearing plane.
The interface to Autodesk Revit is installed automatically during the installation of RFEM 5 or RSTAB 8. Subsequent installation of the plug‑in is possible through the execution of Revit-Installer.exe.
A structural analysis does not only determine and design internal forces and deformations. It also ensures that the forces and moments in a structure are generated in a reliable way and applied to the foundation. Dlubal Software provides a wide range of products for the structural analysis and design of steel and timber connections. The RF-/JOINTS Steel – Column Base add-on module allows you to design footings of hinged and restrained column bases. The design can be performed for column base plates with or without stiffeners.
BIM is often used when it comes to data management in civil engineering. The individual disciplines of architecture, structural design, construction, and structural monitoring are coming closer together. Building Information Modeling makes this possible.. Dlubal Software provides a wide range of formats for data exchange. The following article explains the details of the interface with Autodesk Revit and, in particular, the export settings.
The increasing use of the BIM method in planning buildings also opens up new possibilities for structural engineers. Once a comprehensive 3D model of a building has been created, you want to continue using it for the structural analysis and gain the maximum benefit from it. However, there are also some new challenges for the structural engineer and the software used, which are described in this article.
"A good tool is half the job done": This proverb could be applied equally to the software industry. The more a program is task-tailored, the more efficiently the tasks can be solved. The variety and complexity of today's problems, especially in structural engineering, require specifically tailored solutions. Creating your own programs by means of textual programming requires in-depth knowledge and a great ability to abstract. Understandably, only very few engineering offices face this challenge. For this reason, there are additional software solutions providing the user with a visual development environment.
This technical article deals with the design of structural components and cross-sections of a welded truss girder in the ultimate limit state. Furthermore, the deformation analysis in the serviceability limit state is described.
When designing reinforced concrete components according to EN 1992‑1‑1 [1], nonlinear methods of determining internal forces for the ultimate and serviceability limit states are possible. In this case, the internal forces and deformations are determined with respect to their nonlinear behaviour. The analysis of stresses and strains in cracked state usually provides the deflections, which clearly exceed the linearly determined values.
This article describes the different options for determining the allowable deformation of crane runway girders. Since multi-span beams and flexible lateral supports (sway bracing) are used in practice, this article will show how to select the correct method.
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.
Very small torsional moments in the members to be designed often prevent certain design formats. In order to neglect them and still perform the designs, you can define a limit value in RF‑/STEEL EC3 from which torsional shear stresses are taken into account.
The deformations of the FE nodes are always the first result of an FE calculation. It is possible to calculate strains, internal forces, and stresses based on these deformations and the stiffness of the elements.
Using RF-/FOUNDATION Pro, it is possible to perform geotechnical design according to EN 1997‑1 [1] for single foundations. Subsequently, the program displays detailed information about the influence of the ground water level on the selected design according to EN 1997‑1.
Building Information Modeling is making headlines in building design. While some engineers only use BIM methods for planning, others are dealing with this topic for the first time or rarely have time for it in their daily working routine. However, one topic seems the most important in structural engineering: How can structural engineers benefit from BIM?
Different methods are available for calculating the deformation in the cracked state. RFEM provides an analytical method according to DIN EN 1992-1-1 7.4.3 and a physical-nonlinear analysis. Both methods have different features and can be more or less suitable depending on the circumstances. This article will give an overview of the two calculation methods.
Generally, avoiding cracking in concrete structures is neither possible nor necessary. However, cracking must be limited in a way so that the proper use, appearance, and durability of the structure are not affected. Therefore, limiting the crack width does not mean preventing from the crack formation, but restricting the crack width to harmless values.
The calculation in RFEM is usually carried out in several calculation steps (iterations). It is then possible to consider particular characteristics of the model, such as objects with nonlinear functions. In addition, by using the iterative calculation, nonlinear effects are taken into account that result from changes in deformation and internal forces in case of the second-order analysis or when considering large deformations (cable theory). In case of complex models, geometric linear calculations are usually insufficient.
The calculation of structures based on digital twins is becoming an everyday task in the engineering office. If a digital building model already exists, you want to continue to use the information contained in it as seamlessly as possible. This states extensive requirements with regard to modeling and interfaces for BIM-compatible structural analysis software.
RFEM and the RF-CONCRETE add-on modules provide various options for the deformation analysis of a T-beam in the cracked state (state II). This technical article describes the calculation methods (C) and modelling options (M). Both the calculation methods and the modelling options are not limited to T-beams, but will be only explained using an example of this system.
The response spectrum analysis is one of the most frequently used design methods in the case of earthquakes. This method has many advantages. The most important is the simplification: It simplifies the complexity of an earthquake to such an extent that an analysis can be carried out with reasonable effort. The disadvantage of this method is that a lot of information is lost due to this simplification. One way to mitigate this disadvantage is to use the equivalent linear combination when combining the modal responses. This article explains this option by describing an example.