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.
CFD calculations are in general very complex. An accurate calculation of wind flow around complicated structures is very demanding on time and computational costs. In many civil engineering applications, high accuracy is not needed and our CFD program RWIND 2 enables in such cases to simplify the model of a structure and reduce the costs significantly. In this article, some questions about the simplification are answered.
Large-scale models are models which contain multiple dimensional scales and thus are demanding on computational power. This article will show you how to simplify and optimize the calculation of such models with respect to the desired results.
In this paper, a novel approach was developed to generate CFD models at the community-level by integrating building information modeling (BIM) and geographical information systems (GIS) to automate the generation of a high-resolution 3-D community model to be employed as an input for a digital wind tunnel using RWIND.
The stand-alone program RSECTION is at your disposal for determining section properties and performing stress analysis for thin-walled and massive cross-sections. The program can be connected to both RFEM and RSTAB so that sections from RSECTION are also available in the RFEM and RSTAB library. Likewise, internal forces from RFEM and RSTAB can be imported into RSECTION.
You can use the stand-alone program RSECTION to determine the section properties for any thin-walled and massive cross-sections, as well as to perform a stress analysis. The previous Knowledge Base article titled "Graphical/Tabular Creation of User-defined Cross-sections in RSECTION 1" discussed the basis of defining cross-sections in the program. This article, on the other hand, is a summary of how to determine the section properties and perform a stress analysis.
RSECTION 1 is a stand-alone program for determining section properties for both thin-walled and massive cross-sections, as well as for performing a stress analysis. In addition, the program can be connected to both RFEM and RSTAB: sections from RSECTION are available in the RFEM/RSTAB libraries, and internal forces from RFEM/RSTAB can be imported into RSECTION.
RWIND 2 is a program for generating wind loads based on CFD (Computational Fluid Dynamics). The wind flow numerical simulation is generated around any building, including irregular or unique geometry types, to determine the wind loads on surfaces and members. RWIND 2 can be integrated with RFEM/RSTAB for the structural analysis and design or as a stand-alone application.
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:
In CRANEWAY, the action of a rail as "statically effective" or "statically ineffective" is defined under "Rail‑Flange Connection" in the Details dialog box. This setting controls the calculation of the load introduction length according to EN 1993-6, Tab. 5.1.
In the event of converting or extending a hall, the building owner may want to add a second or third crane to an existing crane runway. Since the original design usually does not consider other cranes, a common solution is to design a minimum distance between the cranes. This is done via the crane technology settings.
General thin-walled cross-sections often have asymmetrical geometries. The principal axes of such sections are then not parallel to the horizontally and vertically aligned axes Y and Z. When determining the cross-section properties, the angle α between the center-of-gravity axis y and the principal axis u is determined in addition to the principal axis-related moments of inertia.
With the SHAPE‑THIN cross‑section properties software, you can create any thin‑walled cross‑section and use it in RFEM or RSTAB as a member cross‑section. SHAPE‑THIN can give all relevant cross‑section values of any cross‑section for a design and stress analysis.
For suspension cranes, the bottom chord of the runway girder is subjected to local flange bending due to the wheel loads in addition to the main load-bearing capacity. The bottom chord behaves like a slab due to these local bending stresses, and has a biaxial stress condition [1].
At the end of the topic on the design of welds on runway beams - after the technical articles about the rail weld seam in the ultimate limit state and the limit state of fatigue - a technical article about web fillet welds now follows. Both the ultimate limit state and the fatigue limit state are considered.
The SHAPE‑THIN stand-alone program determines the characteristic values and stresses of any thin‑walled cross‑sections. Graphic tools and features allow for modeling complex cross‑section shapes. In addition to the graphical input, it is also possible to enter the data in tables. As an alternative, you can import a DXF file and use it as a basis for further modelling. Also, each cross-section can be entered using the cross-section library of Dlubal Software and combined as a part with the user-defined elements.
SHAPE-THIN allows you to calculate section properties and stresses of any cross-sections. If a flange or a web is weakened by bolt holes, you can consider this by using null elements. The stresses are subsequently recalculated with the reduced cross-section values. In this case, it is necessary to pay a special attention to shear stresses. By default, these are set to zero in the area of the null elements. When recalculating shear stresses with the reduced cross-section values and without further adaptation, it turns out that the integral of the shear stresses is no longer equal to the applied shear force. The following example shows in detail how to calculate the shear stress.
A fillet weld is the most common weld type in steel building construction. According to EN 1993-1-8, 4.3.2.1 (1) [1], fillet welds may be used for connecting structural part where the fusion faces form an angle of between 60° and 120°.
Based on the technical article about the ultimate limit state design of rail welds, the following explanation refers to the process of fatigue design of rail welds. In particular, this article explains in detail the effects of considering an eccentric wheel load of 1/4 of the rail head width.
The eccentric wheel load application of 1/4 of the rail head width has to be considered only for fatigue design from damage class S3 according to DIN EN 1993‑6. An additional input option in detail settings allows you to consider this eccentricity for fatigue design at the ultimate limit state as well. By selecting this option, the design with the eccentric load applied is always considered without regard to the damage class.
In addition to arcs and circles, SHAPE-THIN 8.xx allows you to model the following curved cross-section parts: ellipses, elliptical arcs, parabolas, hyperbolas, splines, NURBS (non-uniform rational B-Spline).
SHAPE‑THIN cross‑section properties software provides the option to combine cross‑section parts in a "section" and display the cross‑section properties. Thus, you can determine the values of the individual components in a composite cross‑section.
With the SHAPE-THIN cross-section program, you can model the corner areas of cross-sections in detail: The "Smooth Corner" function fills the corner with an element and automatically connects it with a null element. For this, simply click the corner. Use the "Create Round or Angled Corner" function to round or angle the corner. To do this, specify the fillet radius and click both elements.
In CRANEWAY, the eccentric wheel loading of 1/4 of the rail head width is used for the fatigue design of welds as well as for craneway girder design according to the National Annex of Germany and as of damage class S3.
The design of cross-sections usually requires many different cross-section properties. In RFEM and RSTAB, all required properties of standardized cross-sections are available in the cross-section library and can be used directly for the calculation. If the cross-sections are not standardized, SHAPE-THIN allows you to use these cross-sections, too. You can simply enter the geometry to determine all required cross-section properties. The following example shows the calculation of a shear area on a practical example.
If crane runway girders are designed with flat steel rails, the welding of these rails is always a detail for the design. You can generally select between continuous and intermittent fillet welds as a rail fixing. The following article provides an overview of the design processes and their specific features, especially when using EN 1993-6.
SHAPE‑THIN cross‑section properties software determines the effective section properties of thin‑walled cross‑sections according to Eurocode 3 and Eurocode 9. Alternatively, the program allows plastic design of general cross‑sections according to the Simplex Method. In this process, plastic cross-section reserves are iteratively calculated for elastically determined internal forces. The following example describes the effective cross-section properties in the notching area of a rolled I-section. Afterwards, the results are compared with the plastic analysis.
The buckling analysis of plates with stiffeners is a special task for engineers. For this, EN 1993-1-5 provides three calculation methods: Effective Cross-Section Method, [1], Sect. 4-7; Reduced Stress Method, [1], Sect. 10; Finite Element Methods of Analysis (FEM), [1], Annex C.