Any construction job will be made easier with the help of a crane. But, you have to match the crane and bucket with the jobsite conditions. A crane that can only lift a half-full bucket of concrete or can't reach the entire concrete pour area kills your budget and schedule. To match the crane to the job, you must plan carefully by choosing the right crane boom length, crane size, and layout.
CHOOSING THE BOOM LENGTH
Crane booms are available in either a lattice-type structure or a telescoping cantilever. Lattice-type booms are added in 10-foot increments to obtain the overall desired boom length. Telescopic booms are made up of a series of different size hollow, rectangular or trapezoidal segments fitting into each other. Hydraulic cylinders extend and retract the section. Boom lengths range from 30 to 350 feet.
CHOOSING LIFTING CAPACITY
The rated capacity of a crane is the maximum load lifted under defined conditions. American practice is to control load rating based on stability against overturning. Rated load must not exceed a specified percentage of the tipping load. Cranes can have rated capacities of 6 to 500 tons.
CHOOSING CRANE LAYOUT
To reach all concrete placing areas, the crane may need to be moved. Hydraulic truck-mounted cranes can retract their telescoping booms and outriggers and make a move in 30 to 45 minutes. Cable-controlled crawler-mounted cranes with lattice booms can take as long as 4 hours or more to move. During the move, the concrete crew may be on an expensive break so plan for the fewest possible crane moves for the project.