When wind-induced surface pressures on a building are available, they can be applied on a structural model in RFEM 6, processed by RWIND 2, and used as wind loads for static analysis in RFEM 6.
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.
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.
The Geotechnical Analysis add-on provides RFEM with additional specific soil material models that are able to suitably represent complex soil material behavior. This technical article is an introduction to show how the stress-dependent stiffness of soil material models can be determined.
Given that realistic determination of the soil conditions significantly influences the quality of the structural analysis of buildings, the Geotechnical Analysis add-on is offered in RFEM 6 to determine the soil body to be analyzed.
The way to provide data obtained from field tests in the add-on and use the properties from soil samples to determine the soil massifs of interest was discussed in Knowledge Base article “Creation of the Soil Body from Soil Samples in RFEM 6”. This article, on the other hand, will discuss the procedure to calculate settlements and soil pressures for a reinforced concrete building.
The quality of the structural analysis of buildings is significantly improved when the soil conditions are considered as realistically as possible. In RFEM 6, you can realistically determine the soil body to be analyzed with the help of the Geotechnical Analysis add-on. This add-on can be activated in the model’s Base Data as shown in Image 01.
An elastic foundation can be applied to a member. Thus, the influence of the soil is usually included in the modeling. Member elastic foundations can only be defined for the "Beam" member type.
When calculating foundations according to EC 7 or EC 2, different foundation types or sizes are usually used in one object. However, boundary conditions like the soil parameters, the materials for foundations, concrete covers, and the load combinations selected for design remain the same for all foundations, as a rule.
Often in RFEM, only part of a surface must be loaded, not an entire surface. A typical case of this is soil pressure. For this purpose, there is the option of defining free surface loads. They are surface-independent and are displayed in defined coordinate dimensions in the graphic.
An elastic foundation can be applied to a member. The foundation is used to include the influence of soil in the modeling. Member elastic foundations can only be defined for the "Beam" member type.
In this article, we will look at the design of shear connectors of cross‑laminated timber structures that transfer the longitudinal forces of the shear wall to the soil.
A fluid with a constant density in a homogeneous gravity field exerts a hydrostatic pressure on its comprehensive container wall according to Pascal's law.
RF‑/FOUNDATION Pro allows you to check the allowable eccentricity of the soil pressure resultants. According to DIN EN p;1997‑1/NA, this design is to be carried out with characteristic or representative loads.
Settlement within a structural system can also affect the surrounding structures. The adjacent settlement of separated slabs can be considered with RF-SOILIN using a small trick.
The following study compares the wind pressure on a tall building obtained by RWIND Simulation with the results published by Dagnew et al. at the 11th Americas Conference on Wind Engineering in June, 2009. In this paper, the Commonwealth Advisory Aeronautical Council (CAARC) building is used as a model, and the results of several different numerical methods are compared with experimental data obtained from wind tunnels.
RFEM and RSTAB offer different options to model bored piles. One option is to display bored piles as single-valued supports or hinged columns. Another option is realistic modeling while taking the soil into account by means of applying a member elastic foundation. The two following examples will describe it in detail. However, pile base resistance, skin friction, and soil layers are not considered in this technical article.
The RF-/FOUNDATION Pro add‑on module designs single foundations (foundation plates, bucket and block foundations) for all support forces arising in the RFEM/RSTAB model. The geotechnical designs are performed according to EN 1997-1.
If the wind load for buildings or structures is to be determined by the simultaneous assumption of aerodynamic pressure and suction coefficients on the windward and leeward sides of the building, the correlation of the wind pressure on zones D and E of the wall surfaces may be taken into account.
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.
Cable and tensile membrane structures are regarded as very slender and aesthetic building structures. The partly very complex double-curved shapes can be found using suitable form-finding algorithms. One possible solution is to search for the form via the equilibrium between the surface stress (provided prestress and an additional load such as self-weight, pressure, and so on) and the given boundary conditions.
Wind is the only climatic load acting on every type of structure in every country in the world, unlike snow. The wind speed depends on the geographic location of the building. Currently, this is one of the main reasons for the necessity of regional division (wind zone) and consideration of the altitude stipulated within the official standards; the variation of the dynamic pressures according to the height above the ground for a "normal" site deprived of masking effect should be taken into account as well.
In addition to the reinforced concrete design according to EN 1992‑1‑1, RF-/FOUNDATION Pro allows you to perform geotechnical designs according to EN 1997‑1. In RF-/FOUNDATION Pro, the design of the allowable soil pressure is performed as a ground failure resistance design. If you select CEN as National Annex, you have two options for defining the ground failure resistance. First, you can directly specify the allowable characteristic value of the soil pressure σRk. Second, there is also the option to analytically determine the bearing capacity according to [1], Annex D.
A previous article presented different variants of surface elastic foundations in addition to the traditional subgrade reaction modulus method. The following article describes another method for surface foundation. This method considers the adjacent ground areas by means of a foundation overlap. In this case, foundation parameters refer to the continuing works by Pasternak and Barwaschow.
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.
As in RFEM, load combinations can be generated automatically in RF‑PIPING. This feature is activated by default and creates the recommended load and result combinations for piping design. It is necessary to assign the relevant action category to load cases in order to generate the correct combinations. To do this, new action categories have been implemented specifically for loads on piping. Pressure temperature conditions are generated as the sets of the first (second, third, and so on) load case of the "Pressure" category and the first (second, third, and so on) load case of the "Temperature" category. The default setting can be reviewed or adjusted in the "Grouping of Thermal and Internal Pressure Load Cases for Operating Combinations" dialog box. You can access this dialog box by clicking the corresponding button in the "Piping Load Combinations" tab of the "Load Cases and Combinations" dialog box. This dialog box is automatically offered to check your entries in the case of any change of the load case from the "Pressure" or "Temperature" category.
As of program version x.06.1103, you can enter a soil profile in RF‑/FOUNDATION Pro. This gives you the advantage of setting several soil layers with different soil parameters above and below the foundation base. To enter the soil layers, there is a library with various soil types that can also be extended with user‑defined soils. The user-defined soil profile is shown in an interactive information graphic. Any change (for example, a soil thickness modification) is reflected in the graphic immediately.