Experimental Studies on the Influence of Different Support Conditions and Structural Systems for the Lateral Torsional Buckling Behaviour of Steel Structures

Abstract

AbstractThe use of slender steel members promotes the competitiveness of steel structures in structural engineering. However, it requires an efficient design, especially for the stability behaviour including lateral torsional buckling which is usually verified by the simplified design method with reduction factors. This method is based on the model of a simply supported member with ideal fork boundary conditions at the ends. However, commonly used joints in engineering practice, such as typical main and secondary beam joints, deviate from the idealisations of these ideal fork restraints. And at system level, there are only a few simply supported members, more common are structural systems such as continuous girders or frames. So far, there is a lack of knowledge on the influence of common joints used in engineering practice and structural system effects on the load‐bearing capacity. This paper deals with the results of experimental studies carried out within a German national (FOSTA) research project. The lateral torsional buckling behaviour of different support and boundary conditions as well as structural systems is investigated for hot‐rolled steel members with doubly and mono‐symmetric sections. In total, 14 tests on support conditions are carried out at the University of Stuttgart and 20 tests on two‐span members at the Ruhr‐Universität Bochum. The aim is to develop easy‐to‐use design rules that consider the effects of realistic conditions and structural system effects on the lateral torsional buckling resistance.