FAQ >> Crane And Mobile Crane

Crane And Mobile Crane

Cranes and airplanes have something in common other than the airspace they share. The early history of aviation belongs to the barnstormers and bush pilots who pushed their rudimentary craft to the limits with hardly a thought for risk. Likewise, crane operation was once a seat-of-the-pants skill governed largely by the notion that lifting equipment could be used right up to the point of tipping over.

Both cranes and aircraft of early vintage were machines with modest capabilities that responded almost like extensions of the operators themselves. Machines were relatively small and inexpensive, and pilots frequently survived crashes while crane operators usually walked away. Collateral damage to persons and property was usually inconsequential. Not so today where property damage claims can be stratospheric and the public is often be in harm's way. Society today is far less tolerant of accidents.

A high-performance contemporary crane cannot be run from intuition; an operator who tries to work that way will not be warned by his gut of an approaching failure and will be blindsided when it inevitably happens. And when it does happen the cost will be intolerable. More cerebral demands on the operator reflect changes both in construction equipment and construction culture. Risk managementnot bravado-is the new order of the day in mobile crane practice. An underlying rule of this practice is that a balance must be struck between safety and economy. Success demands well-structured organization and unrelenting attentiveness to details.

A successful mobile crane operation is not simply one that has been carried out without mishap. True success has been achieved only when, in addition, the operation has been executed at the lowest possible cost consistent with tolerable risk. The measurement of risk management success is imprecise, however, and may be hard to appreciate by considering only an individual operation. But, over time, repetitive accident-free and productive crane use will show up favorably on the balance sheet.

There are proven risk management measures, such as worker training and rigorous equipment maintenance, to name but two. Another key measure for mobile-crane use is planning. The need will vary widely from operation to operation, to be sure. Sometimes an hour reviewing site conditions, loads, and equipment characteristics is sufficient. At the other extreme, some operations demand hard months of preparation.

This chapter is concerned with the details of planning. It presents steps that would be carried out in selecting a mobile crane for an assignment and putting it to work, in particular.

  • Evaluating access for the crane to reach the site and get set up for operation
  • Selection and positioning
  • Assessing working clearances
  • Determining loads imposed by the crane on the supporting surface
  • Specifying supports under the crane
  • Special arrangements such as pick-and-carry and multiple crane lifts

Knowing these elements of planning can help decide which are necessary for any one situation and how elaborate the planning process must be. Mathematical procedures are introduced and explained which may not always be required, but can be valuable resources at times. However, planning a crane installation is an art requiring extensive field experience and knowledge of cranes. The material given here can be put to good use by those who have that experience and knowledge and can be invaluable to those who wish to gain it.

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