A bending beam is a beam that is mainly subjected to bending.
Features
A bending beam is characterized by transferring loads mainly by shear forces and bending; that is, the loads that act perpendicular to the member axis of the bending beam (see Image 01). The resulting bending moments in the member lead to deformation of the member axis.
In the case of bending, a distinction must be made between uniaxial and biaxial (double) bending.
Application
Bending beams can be dimensioned both as one-part and as multi-part cross-sections.
Due to the existing bending, it is necessary to achieve a high section modulus in the cross-section of a bending beam so that the stresses and deformations are optimized and the ultimate and serviceability limit state design checks are fulfilled. This is generally achieved by providing as much cross-section area as possible to the outside or above and below (for loading from above/below). In steel construction, for example, this results in a double T‑section that is perfectly suited as a bending beam (see Image 02).
In timber and concrete structures, rectangular cross-sections are more common due to their practicality. A typical example of a bending beam in concrete structures is the T‑beam, in which, depending on the planning and construction method, the supporting slab acts up to a certain width (see Image 03).
Bending Beam in RFEM and RSTAB
In the cross-section library of RFEM and RSTAB, you can select any cross-section or define it yourself (see FAQ "Parameterized Sections in Cross-Section Library").
A beam member that is set by default is typically used as a member type, which corresponds to the properties of the bending beam. Another option, for example, for modeling T-beams, is the "Rib" member type.
