Method for erecting an at least two-piece main boom for a lattice-boom crane and lattice-boom crane built accordingly

Method for erecting a main boom of a lattice-boom crane with a lower boom portion, hinged to the upper carriage of the crane at a first point, and an upper boom portion, connected during assembly by an articulated link to the lower boom portion, comprising:

• producing a starting position, in which the main boom attached to the upper carriage of the crane is supported on at least one second point on the ground spaced apart from the upper carriage;
• shortening the effective lever arm of the main boom by producing an angle position between the lower and the upper boom portion, maintaining the second support point until the tilting moment producible by the boom weight is smaller than the standing moment of the crane;
• lifting the angled boom portions by pivoting around the hinge point on the upper carriage of the crane;
• and
• aligning the lower and upper boom portions into a crane operating position.