Truck cranes have a high ground bearing pressure,
ranging from 75 to 100 psi due to the pneumatic tires on
which the machine travels. On a firm, dry surface, a
truck carrier can climb a 40-percent grade. Depending
on the design of the carrier, the turning radius can range
from 50 to over 90 feet. This high turning radius limits
Before any crane travels to a jobsite, the crane crew
supervisor must visually review the planned travel route
to determine if low wires, low overpasses, narrow
bridges, or other unsafe obstacles exist. The absolute
limit of approach for power lines (fig. 12-7) is the
1. 0 to 125,000 volts, 10 feet
2. 125,000 to 250,000 volts, 15 feet
3. Over 250,000 volts, 25 feet
Anytime you are traveling with a crane, stay a
minimum of 4 feet from any electrical power source.
When traveling with a truck-mounted crane
equipped with a lattice boom, do NOT rest the boom on
the cradle, as the lower cords of the boom can be dented
if the boom bounces while traveling. Position the boom
2 to 4 inches above the cradle.
Truck- and wheel-mounted cranes are rated at 85
percent of the minimum weight that can cause the crane
to tip at a specified radius with the basic boom. The
truck carrier is equipped with outriggers that provide
more stability for the crane; therefore, when you are
making crane lifts, the outriggers should always be used.
As outlined in the COMSECOND/COM-
THIRDNCBINST 11200.1, Naval Mobile Construction
Figure 12-7.Limit of approach for power lines.
Figure 12-8.Truck-mounted crane quadrants of operation.