Salah R. Al Zaidee - Department of Civil Engineering, College of Engineering, University of Baghdad, Iraq.
Ehab G. Al Hasany - Department of Civil Engineering, College of Engineering, University of Baghdad, Iraq.

In this paper, different end connection types for steel beams with I shape have been investigated to show how they affect the lateral-torsional buckling (LTB) behavior and the critical buckling load capacity of thebeams. For this purpose, an elaborated finite element model has been prepared. In this model, a quadrilateral shell element with eight nodes and with six degrees of freedom per node is used to simulate beam web andflanges. The lateral torsional buckling strength, for a single span beam subjected to two point loads located at thirds of beam span, has been estimated using an Eigen analysis with subspace algorithm. The proposedfinite element model has been verified based on comparison with an experimental work. Then, the model adopted to study effects of different connection types and their details on lateral-torsional buckling of beams.Finite element results indicate that only connection type, simple or rigid, has a significant effect on lateral torsional buckling of beams where it has been found that beams with rigid connection have strength up to 3 times that ofthe corresponding beams with simple connections. Finite element analysis also indicates that different details of rigid connections, namely weldedflange, bolted flange, unstiffened end plate, and stiffened end plate, have insignificant effect on the lateral torsional buckling strength of beams with rigid connections.

Lateral torsional buckling, Steel beams, Finite element modelling, Steel connections