Crane boom loading

Crane and rigging safety is of extreme importance to the construction industry. Much of this type of work is performed in congested areas where the general public can easily become involved in an accident.
Hazardous loading of crane booms, which could lead to either overturning the crane or to buckling the boom, can be avoided if you understand crane ratings. Every construction crane should be provided with a chart showing its rated capacity. This rated capacity can be safely handled if you pay attention to the following points:
1. The safe load depends upon the boom length and the radius. Make sure that you know what length of boom you are using. Remember that radius is measured from the center of rotation not from the boom foot pin.
2 . The published load does not include the weight of the hook or materials handling devices. Subtract the weight of equalizer jobs, concrete buckets, or job extension from the rated loads to determine the weight of material that can be handled.
3. Ratings are based on operating on firm ground and in the case of mobile cranes with the outriggers fully extended. Make sure that the crane is not operating on ground that is too soft or with outriggers that are not properly blocked and extended.
4. Ratings are based on operating on level ground. Operating on grades increases boom stress. If you pick up a load on the high side of a slope and swing to the low side, the radius will increase and can cause the crane to tip. If operating at high boom angles, a swing from the low side to the high side can cause the boom to collapse over the cap.
5 . Avoid fast operations. Fast swings cause the load to swing out, thus increasing the radius. Rapid hoisting or braking of the load increases the boom stresses and can overload the rigging.
6. Do not handle heavy loads with a large surface area when there are high winds. Wind gusts can create an unstable condition.
7. Make sure the crane is properly rigged, that it has the correct counterweight, the proper boom, the right boom mounting position, the gantry properly rigged, and has adequate parts of line.
8. Avoid traveling with a heavy load. The boom is subjected to shock and bending stresses if moving over uneven ground, and swinging of the load creates inertia forces which can cause collapse of the boom.

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