Steel Buildings in Europe

Part 3: Actions 3 - 11 The determination of the actions induced by cranes is complex, as they include many parameters such as:  Weight of the crane and safe working load  Stiffness of both the crane structure and the runway girders  Speed and acceleration of the crane  Design of the crane (wheel drives, guidance systems, etc.). The characteristics of the crane generally have to be supplied by the crane manufacturers. 2 3 4 5 6 1 2 7 7 7 7 1 8 8 1 Axis of wheels 2 Bogies 3 Main girders of the crane 4 Crab 5 motor drive unit 6 Hook 7 Axes of runway beams 8 Axis of track wheels Figure 6.1 Main components of a crane The relevant standard which specifies these actions is EN 1991-3 ‘Actions on structures – Actions induced by cranes and machinery’. The variable crane actions are separated into:  Variable vertical crane actions caused by self weight of the crane and the hoist load  Variable horizontal actions caused by acceleration or deceleration or by skewing or other dynamic effects. 6.2.2 Vertical actions Vertical actions include dead loads (self weight of the crane, safe working load, hook block, etc.) The distribution of these dead loads is generally assumed on the basis of simply supported beams, considering both the main girders and the secondary beams over the bogies. Two positions of the crab are generally considered to obtain the worst load arrangement on the crane runway: crab located in the middle of the crane span or crab located at the minimum distance of hook approach from the runway.