Factors k and k_w

Factor k

The k-factor refers to end rotation on plan, it is analogous to the effective length parameter for a compression member.

The k-factor is set in the buckling group by default to 1.00 which corresponds with fork supports at both extremities of the considered LTB-span.

The picture below illustrates 3 use cases for k:

• Use case A: Fork supports at both extremities of the considered LTB-span. Lateral displacement is not restricted near both extremities.

• Use case B: Fork support at 1 one extremity, Fixed support at the other extremity of the considered LTB-span. Lateral displacement is restricted near the fixed support.

• Use case C: Fixed support at both extremities of the considered LTB-span. Lateral displacement is restricted near both extremities.

Factor k_w

The k_w-factor refers to end warping and varies between 0.50 for full restraint to 1.00 for no restraint.

The k_w-factor is set in the buckling group by default to 1.00 and should only be modified in case special provisions are made for warping restraint.