LT buckling parameters

First part "LTB effect" of the window contains basic settings for the certain lateral torsional buckling direction. LT buckling verification can be switched of with the help of "Neglect LTB" setting. It's also possible to specify different basic sector length l₁ for the calculation of LT buckling length.

The part "Beam and load type" contains several options for specifying the analysis parameters in accordance with table 6.1 of EN 1995-1-1 (end conditions and load position). The value of ratio between the effective length l_ef and the span l is selected according to these inputs. These options are available:

	The default setting of the program, end conditions and load type aren't specified, effective length l_ef isn't calculated. The analysis of buckling cannot be performed for this option.
	Simply supported beam with constant moment. Ratio l_ef/l is 1.0.
	Simply supported beam with uniformly distributed load. Ratio l_ef/l is 0.9.
	Simply supported beam with concentrated force at the middle of the span. Ratio l_ef/l is 0.8.
	Cantilever with uniformly distributed load. Ratio l_ef/l is 0.5.
	Cantilever with concentrated force at the free span. Ratio l_ef/l is 0,8.

The load position with respect to the centre of gravity ("on the top", "in the middle", "at the bottom") has to be specified in the most of cases. These options respect the note in table 6.1. The effective length l_ef is increased by 2h for the load applied at the compression edge and decreased by 0,5h for the load applied at the tension edge of the beam.

The values specified in the table 6.1 are valid only providing that the torsional rotation is prevented at member supports.

Window "Buckling parameters"

GEO5

FINEC

TRUSS4

FIN EC

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