Studi Efek Kontinuitas Pada Tekuk Torsi Lateral Balok Terlentur

Abstract

Steel beams with bending moment, have a kind of instability called lateral torsional buckling. The critical
moment of a beam depends on its length, distribution of bending moment and on its end condition. Often,
the beam is laterally supported on some points of the beam to increase critical moment. In AISC
Specification for Structural Steel Buildings takes the lengh as the unbraced length, which means the
distance between these lateral bracing. The AISC doesnot taken into account the influence of the parts of
the beam which continuously connected to the part of the beam which is being considered. In this
research, the influence of the other parts of the beam is studied. Calculation of critical moment is
performed using finite difference method considering the beam as a whole, with its lateral support. A
computer program is developed to performed the analysis. The results of this study is that the when the
whole beam is analysed, the critical moments is increased significantly compared to critical momet from
AISC method. For the beam being considered in this study, the increase is up to 49%. The conclusions of
this study is that the analysis of critical moment for lateral torsional bukling, has to be performed
considering all part of the beam.