LT buckling parameters
First part "Buckling 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 following parameter is the moment distribution according to the table 6.6 of EN 1993-1-1. The appropriate value of the correction factor kc is selected according to the moment distribution. There are some additional parameters for certain moment distribution styles. The proportion ψ of bending moments at the beginning and end pf the sector has to be specified for trapezoidal distribution. The load position with respect to the centre of gravity has to be specified in the most of cases. The position is specified as a factor with the interval <0;1>, the value 0 means bottom (left) edge and the value 1 means upper (right) edge of the cross-section.
The part "Parameters" contains an option for input of supporting method of the sector (end conditions). The end conditions affect the coefficient kz. This factor reduces the fundamental buckling length and is used for the calculation of the critical moment. The value of the coefficient kz is 1.0 for end conditions "hinge-hinge" and 0.5 for the end conditions "fixed-fixed". The end conditions for torsion have to be specified for moment areas with variable direction. This parameter affects the coefficient kw, that is used for the calculation of the parameter κwt. The values of the factor kw are identical to the values of kz. The analysis of lateral torsional buckling is described in the theoretical part of help.
Window "LTB parameters"