Using RF-CONCRETE Members, concrete column design is possible according to ACI 318-14. Accurately designing concrete column shear and longitudinal reinforcement is important for safety considerations. The following article will confirm the reinforcement design in RF-CONCRETE Members using step-by-step analytical equations as per the ACI 318-14 standard, including required longitudinal steel reinforcement, gross cross-sectional area, and tie size/spacing.
For structural components consisting of slabs, it is necessary to perform shear design on the locations with concentrated load introduction, applying the punching shear design rules according to Sect. 6.4 of EN 1992‑1‑1 [1]. The concentrated load introduction is present on the individual locations; for example, by columns, concentrated load, or nodal supports. In addition, the end of linear load introduction on slabs is also regarded as concentrated load introduction. For example, this includes wall ends, wall corners, and ends or corners of line loads and line supports. You can perform the punching shear design for floor slabs or foundations, considering the existing available plate topology about the designed node of punching shear. The punching shear design according to EN 1992‑1‑1 checks that the acting shear force vEd does not exceed the resistance vRd.
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°.
The fundamental requirements of a structural system are (according to the basis of structural design) sufficient ultimate limit state, serviceability, and resistance. Structures must be designed in such a way that no damage occurs due to events such as the impact of a vehicle.
The secondary reinforcement according to DIN EN 1992-1-1 9.2.1 is used to ensure the desired structural behavior. It should avoid failure without prior notification. The minimum reinforcement has to be arranged independently of the size of the actual loading.
DIN EN 1998-1 with the National Annex DIN EN 1998-1/NA specifies how to determine seismic loads. The standard applies to structural engineering in seismic areas.
Downstand beams or T-beams are often used in reinforced concrete structures. In contrast to the previous representation and calculation options where, for example, a downstand beam was considered as a fixed support and the determined support reaction was applied to a separate member structure using a T-beam section, the ultimate structural FEA software like RFEM allow you to consider the structure as a whole and thus achieve a more precise analysis.
The stiffening of timber structures is usually carried out by means of timber panels. For this purpose, structural components consisting of slabs (chipboard, OSB) are connected with members. Several articles will describe the basics of this construction method and the calculation in the RFEM program. This first article describes the basic determination of the stiffnesses as well as the calculation.
Cross-section properties in RFEM and RSTAB include different types of shear areas. This technical article explains the calculation and meaning of various values.
Fin plate connections are a popular form of pinned steel connection and are commonly used for secondary beams in steel structures. They can be used easily in beam structures arranged on the top edge (for example, working platforms). Manufacturing expenditures in the workshop as well as the onsite assembly costs are normally manageable. The design seems to be completed easily and quickly, but it has to be put into perspective to a certain extent in the following text. Moreover, this connection type is basically possible as a pinned beam-to-beam or pinned beam-to-column connection; the former case is the more common one in design practice.
When it comes to wind loads on building type structures as per ASCE 7, numerous resources can be found to supplement design standards and aid engineers with this lateral load application. However, engineers may find it more difficult to find similar resources for wind loading on non-building type structures. This article will examine the steps to calculate and apply wind loads as per ASCE 7-16 on a circular reinforced concrete tank with a dome roof.
For crane runways with large spans, the horizontal load from skewing is often relevant for the design. This article describes the origin of these forces and the correct input in CRANEWAY. The practical implementation and the theoretical background are discussed.
In this example, the design resistance of an end plate according to EN 1993-1-8 [1] is to be determined; the other components are not described here. To check the results, the dimensions of the connection IH 3.1 B 30 24 of Typified Connections [2] were used. S 235 material and bolts with strength 10.9 are used.
Slender bending beams that have a large h/w ratio and are loaded parallel to the minor axis tend to have stability issues. This is due to the deflection of the compression chord.
This example is described in technical literature [1] as Example 9.5 and in [2] as Example 8.5. A lateral-torsional buckling analysis must be performed for a principal beam. This beam is a uniform structural member. Therefore, the stability analysis can be carried out according to Clause 6.3.3 of DIN EN 1993-1-1. Due to the uniaxial bending, it would also be possible to perform the design using the General Method according to Clause 6.3.4. Additionally, the determination of the moment Mcr is validated with an idealized member model in line with the method mentioned above, using an FEM model.
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.
In the case of combined FEM structures (surface and member elements) as well as folded plate structures, it is possible to attribute a beam structure for the design on a member to a fictitious T-beam cross-section, whose geometry depends on the effective width. When using the "Rib" member type in RFEM, the stiffness is represented by a slab component (surface element) and a web component (member element). This approach has some design specifics that are explained in this article.
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.
The RF-/STEEL EC3 add‑on module performs a detailed cross‑section classification on each design before the design is carried out. Thus, the susceptibility to local buckling of all cross-section parts is evaluated. The defined cross-section class has an effect on the resistance and rotational capacity determination.
Eurocode 2 provides two ways to perform a crack width design. On one hand, the crack width design according to 7.3.3 can be performed without direct calculation by means of tables for the limitation of the member spacing and diameter. On the other hand, the crack width wk can be determined directly according to 7.3.4 and compared to a limit value.
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].
According to EN 1993‑1‑1 [1], it is necessary to use the equivalent geometric imperfections with values that reflect the possible effects of all types of imperfections. EN 1993‑1‑1, Section 5.3, specifies basic imperfections for the global analysis of frames as well as member imperfections.
The classification of cross-sections is intended to determine the limits of resistance and rotational capacity due to local buckling of cross-section parts. In EN 1999‑1‑1, 6.1.4.2 (1), four classes are defined.
Shell buckling is considered to be the most recent and least explored stability issue of structural engineering. This is due less to a lack of research activities than to the complexity of the theory. With the introduction and further development of the finite element method in structural engineering practice, some engineers no longer have to deal with the complicated theory of shell buckling. Evidence of the problems and errors to which this gives rise is very well summarized in [1].
In this technical article, a hinged column with a centrally acting axial force and a linear load that acts on the major axis are designed according to EN 1993-1-1 with the aid of the RF-/STEEL EC3 add-on module. The column head and column base are assumed as a lateral and torsional restraint. The column is not held against rotation between the supports. The cross-section of the column is an HEB 360 from S235.
Utilize the RF-/STEEL Cold-Formed Sections module extension to perform ultimate limit state designs of cold-formed sections according to EN 1993-1-3 and EN 1993-1-5. In addition to the cold-formed cross-sections from the cross-section database, you can design general cross-sections from SHAPE-THIN.
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).
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.