P 251 - Design of single-span and continuous beams made of round-edged U-steel (DIN 1026) according to the ultimate load method, taking into account a rotational bedding and a normal force load

DIN 18800 also deals with beams with a U-section. However, they require a load in the shear centre, which cannot be realised in practice. The difficulty with these beams lies in the planar torsion that occurs in addition to the bending and normal force loading, so that this problem can only be dealt with using methods that take spatial failure into account. In contrast to beams with I-section, where the planar and the spatial failure (lateral-torsional buckling) can be analysed in separate verifications, this separation is not possible for beams with U-section, so that new ultimate loads including the spatial failure had to be determined here. The present work determines the ultimate loads of single-span and continuous beams with a U-section, loaded by a line load, a compressive force and any existing rotational bedding, and prepares these in the form of ultimate load tables and design formulae for practical application. The use of these tables provides steel fabricators, architects and users with a simple, fast and cost-effective design basis as well as a realistic statement about the safety of the structure. In addition to these investigations, an EDP programme (DOS operating system) has been developed with which the load-bearing capacity for an existing beam or the required profile for a specific system with a given load can be easily determined. This programme can be obtained for a nominal fee from the Institute for Structural Analysis at the University of Karlsruhe, Kaiserstr. 12, 76131 Karlsruhe. STUDIENGESELLSCHAFT STAHLANWENDUNG e.V.