Lateral-Torsional Buckling Resistance of Crane Runway Girders

Abstract

The paper presents the method of design crane girders of a mono- and bisymmetrical cross-section. In the paper authors investigate unrestrained crane beams. Approach presented in Seeselberg [5] was complemented with possibility of easy hand calculation according to alternative method [2]. Results coming from different sources were compared. The focus was on monosymmetric sections of I-rolled profiles reinforced by welded angles, which are commonly used in crane beams designs. Their biggest advantage is high stiffness with respect to the weaker axis. As a result, the horizontal deflection of the beam is reduced, but verification of load capacity of such an element is quite complicated. The paper presents the relationships that allow design of these elements using simple formulas, which may be implemented in a spreadsheet. Simultaneously, a simplified method has been proposed, in which, with a reduced workload, results with an error at an acceptable level are obtained. Additionally, structural verification of the load capacity of the crane girder can then be performed only using the free LTBeam program, used to determine the critical moment of lateral torsional buckling.