Lateral-Torsional Buckling (LTB) is a phenomenon that occurs when a beam or structural member is subjected to bending and the compression flange is not sufficiently supported laterally. This leads to a combination of lateral displacement and twisting. It is a critical consideration in the design of structural elements, especially in slender beams and girders.
Both the determination of natural vibrations and the response spectrum analysis are always performed on a linear system. If nonlinearities exist in the system, they are linearized and thus not taken into account. They are caused by, for example, tension members, nonlinear supports, or nonlinear hinges. This article shows how you can handle them in a dynamic analysis.
Compliance with building codes, such as Eurocode, is essential to ensure the safety, structural integrity, and sustainability of buildings and structures. Computational Fluid Dynamics (CFD) plays a vital role in this process by simulating fluid behavior, optimizing designs, and helping architects and engineers meet Eurocode requirements related to wind load analysis, natural ventilation, fire safety, and energy efficiency. By integrating CFD into the design process, professionals can create safer, more efficient, and compliant buildings that meet the highest standards of construction and design in Europe.
To be able to evaluate the influence of local stability phenomena of slender structural components, RFEM 6 and RSTAB 9 provide you with the option of performing a linear critical load analysis on the cross-section level. The following article explains the basics of the calculation and the result interpretation.
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).
Modal analysis is the starting point for the dynamic analysis of structural systems. You can use it to determine natural vibration values such as natural frequencies, mode shapes, modal masses, and effective modal mass factors. This outcome can be used for vibration design, and it can be used for further dynamic analyses (for example, loading by a response spectrum).
In accordance with Sect. 6.6.3.1.1 and Clause 10.14.1.2 of ACI 318-19 and CSA A23.3-19, respectively, RFEM effectively takes into consideration concrete member and surface stiffness reduction for various element types. Available selection types include cracked and uncracked walls, flat plates and slabs, beams, and columns. The multiplier factors available within the program are taken directly from Table 6.6.3.1.1(a) and Table 10.14.1.2.
For the design of concrete surfaces, the rib component of the internal forces can be neglected for the ULS calculation and for the analytical method of the SLS calculation, because this component is already considered in the member design. To do this, select the check box in the "Details" dialog box. If no rib was defined, this function is not available.