Column Erection

Ask the company that supplied the cranes and operatives. They will have been working to one.

By using the 2nd crane at the bottom of the column the movement of the bottom is controlled. It goes where you want it to, not where it wants to go on its own.

Analogous to why a leash is used to walk a dog, to keep control of it and make sure it goes where you want it to!

Good Luck, Old Salt

• For erection of that type of heavy weight of columns, there must be a rigging study to be prepared by a rigging specialist. And in this case, there must be a two cranes (main & tail), and the loading charts must be available to whom preparing the rigging study to find the permissible load at certain radius for each crane to assure the correct selection of each crane capacity.

• The rigging study includes selection of optimum size of wire ropes and shackles from the applicable charts. And the rigging study must include a valid certificate of calibration for each crane, wire rope and shackle. The rigging study may include a diagrammatic sketches for all steps of loading and maneuvering.

• The rigging study must be reviewed and approved by the owner or his representative before starting of the erection work.

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See this site: http://www.liftplanner.net/

What you saw was a safety measure for the equipment and protecting the load from getting damage.

During the lifting of most any piece there is a moment when the piece first clears from where it has been at rest, in this case you had a 38T object that you did not want to rotate wildly, property of steel cable going under load, nor swing out of control, a pendulum motion that could topple the crane or swing into something else.

Yes there lifting & erection plans that are taught to the crane operators in order to safely lift heavy peices. Even loades as light as 3,000 lb have caused crane accendents, due to the boom being out too far or the load swinging in to the crane, other objects,buildings or equipment.