72 Results
View Results:
Sort by:
Moment frame design according to AISC 341-16 is now possible in the Steel Design add-on of RFEM 6. The seismic design result is categorized into two sections: member requirements and connection requirements. This article covers the required strength of the connection. An example comparison of the results between RFEM and the AISC Seismic Design Manual [2] is presented.
The design of cold-formed steel members according to the AISI S100-16 is now available in RFEM 6. Design can be accessed by selecting “AISC 360” as the standard in the Steel Design add-on. “AISI S100” is then automatically selected for the cold-formed design (Image 01).
When designing bending-resistant connections from I-beams, the connection is dissolved into the individual parts. For these basic components of a joint, there are separate formula calculators for load-bearing capacity and stiffness. In RFEM and RSTAB, frame joints can be designed using the RF-/FRAME-JOINT Pro add-on module.
In January 2015, DIN Committee NA 005‑08‑23 Steel Bridges applied the introduction of a modification in equation 10.5 of DIN EN 1993‑1‑5. This involves the interaction of longitudinal and transverse pressure in a buckling analysis. Now, the interaction equation provides for auxiliary factor V, which is calculated from the reduction factors of the longitudinal and transverse stresses.
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.
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.
Table 3.1 of EN 1993‑1‑8:2010‑12 defines the nominal values of the yield strength and the ultimate limit strength of bolts. The bolt classes given here are 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 10.9. The note for this table states that the National Annex may exclude certain bolt classes. For the NA of Germany, these are the bolt classes 4.8, 5.8, and 6.8.
When designing a steel cross-section according to Eurocode 3, it is important to assign the cross-section to one of the four cross-section classes. Classes 1 and 2 allow for a plastic design; classes 3 and 4 are only for elastic design. In addition to the resistance of the cross-section, the structural component's sufficient stability has to be analyzed.
The product range of Dlubal Software contains various modules for the design of steel and timber connections. The RF-/JOINTS Steel – Column Base add-on module allows you to analyze footings of hinged or restrained steel column bases. The fastener selection, foundation geometry, and material quality are crucial for the cost-effective and safe design of the column base.
The critical factor for lateral-torsional buckling or the critical buckling moment of a single-span beam will be compared according to different stability analysis methods.
This example will show what you should consider when you perform column design for bending and compression with regard to the internal forces from load combinations and result combinations.
When connecting tension-loaded components with bolted connections, the cross-section reduction due to the bolt holes must be taken into account in the ultimate limit state design. This article describes how the design of the tension resistance according to DIN EN 1993‑1‑1 can be performed with the net cross-section area of the tension member in the RF‑/STEEL EC3 add-on module.
In the following example, the stability analysis of a steel frame can be performed according to the General Method in compliance with EN 1993‑1‑1, Sect. 6.3.4 in the RF‑/STEEL EC3 add-on module. The first of my three posts shows the determination of the critical load factor for design loads required by the design concept, which reaches the elastic critical buckling load with deformations from the main framework plane.
A single-span beam with lateral and torsional restraint is to be designed according to the recommendations of Eurocode 3 and AISC. If the beam does not reach the required load-bearing capacity, it must be stabilized.
Closed circular cross-sections are ideal for welded truss structures. The architecture of such constructions is popular when designing transparent roofs. This article shows the special features of the connection design using hollow sections.
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.
A site joint consisting of hollow sections with end plates will be designed. It is the bottom chord of a truss that has to be divided for transport reasons.
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°.
In the RF‑/HSS add‑on module, you can analyze the connections for nodes at which hollow sections join. RF‑/HSS performs the ultimate limit state designs according to EN 1993‑1‑8:2005.
The RF‑/STEEL EC3 add-on module can perform the design of fillet welds for all parametric, welded cross-sections of the cross-section library. For this, the option must be activated in the detail settings of the module. As an alternative, you can also use a surface model for the design.
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).
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.
A welded connection of an HEA cross-section under biaxial bending with axial force will be designed. The design of welds for the given internal forces according to the simplified method (DIN EN 1993-1-8, Clause 4.5.3.3) by means of SHAPE-THIN will be performed.
The design of cold-rolled steel products is defined in EN 1993-1-3. Typical cross-section shapes are channel, C, Z, top hat, and sigma sections. These are cold-rolled steel products made of thin-walled sheet metal that has been cold-formed by roll-forming or bending methods. When designing the ultimate limit states, it is also necessary to ensure that local transverse forces do not lead to compression, crippling of the web, or local buckling in the web of the sections. These effects can be caused by local transverse forces by the flange into the web, as well as by support forces at the supported points. Section 6.1.7 of EN 1993-1-3 specifies in detail how to determine the resistance of the web Rw,Rd under local transverse forces.
Steel connections in RFEM 6 are defined as an assembly of components. In the new Steel Joints add-on, universally applicable basic components (plates, welds, auxiliary planes) are available for entering complex connection situations. The methods with which connections can be defined are considered in two previous Knowledge Base articles: “A Novel Approach to Designing Steel Joints in RFEM 6" and “Defining Steel Joint Components Using the Library".
The European standard EN 1993-1-8, Section 4.5.3.3. provides the user with a simplified method for the ultimate limit state design of fillet welds. According to the standard, the design is fulfilled if the design value of the resultant acting on the fillet weld area is smaller than the design value of the weld's load-bearing capacity. Thus, if you want to dimension the weld for a surface model, you will be faced with a variety of results due to the nature of FEM calculations. Therefore, we show in the following text how to determine the force components from the model.
The RF‑STABILITY and RSBUCK add‑on modules for RFEM and RSTAB allow you to perform eigenvalue analysis for frame structures in order to determine critical load factors, including the buckling modes. Several buckling modes can be determined. They provide information about the model areas bearing stability risks.
The stability checks for the equivalent member design according to EN 1993-1-1, AISC 360, CSA S16, and other international standards require consideration of the design length (that is, the effective length of the members). In RFEM 6, it is possible to determine the effective length manually by assigning nodal supports and effective length factors or, on the other hand, by importing it from the stability analysis. Both options will be demonstrated in this article by determining the effective length of the framed column in Image 1.
- 000945
- Add-on Modules
- RF-FRAME-JOINT Pro 5
-
- JOINTS Steel | Column Base 8
- JOINTS Steel | DSTV 8
- JOINTS Steel | Pinned 8
- JOINTS Steel | Rigid 8
- JOINTS Steel | SIKLA 8
- JOINTS Steel | Tower 8
- JOINTS Timber | Steel to Timber 8
- JOINTS Timber | Timber to Timber 8
- RF-JOINTS Steel | SIKLA 5
- RF-JOINTS Steel | Column Base 5
- RF-JOINTS Steel | DSTV 5
- RF-JOINTS Steel | Pinned 5
- RF-JOINTS Steel | Rigid 5
- RF-JOINTS Steel | Tower 5
- RF-JOINTS Timber | Steel to Timber 5
- RF-JOINTS Timber | Timber to Timber 5
- FRAME-JOINT Pro 8
- Steel Structures
- Timber Structures
- Steel Connections
- Eurocode 3
- Eurocode 5
In addition to the result tables, you can create three-dimensional graphics in RF‑/FRAME‑JOINT Pro and RF‑/JOINTS. This is a realistic representation of a connection to scale.
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.