NCCCO Ground Bearing Pressure and Outrigger Setup 2

Question 1

A crawler crane weighs 200,000 pounds and each track pad has a total ground contact area of 2,000 square inches. What is the ground bearing pressure under each track in pounds per square inch (psi)?

Accepted Answer

50 psi

Answer

100 psi

Answer

200 psi

Answer

400 psi

Question 2

Why must outrigger pads be used on outriggers even when working on concrete surfaces?

Accepted Answer

To spread the point load over a larger area and reduce pressure on the concrete and underlying soil

Answer

To protect the crane's outrigger floats from damage

Answer

Concrete does not require pads; pads are only for soil

Answer

To provide a level surface for the outrigger

Question 3

During a pre-lift check, the crane operator observes that one outrigger pad is sinking into soft ground more than the others. What is the appropriate action?

Accepted Answer

Stop the lift immediately and add more cribbing or a larger pad to distribute the load

Answer

Continue the lift but watch carefully for further sinking

Answer

Reduce boom angle to lower the load on that outrigger

Answer

Lift the load quickly before the ground fails completely

Question 4

What is the primary purpose of extending outriggers to their full width before making a lift?

Accepted Answer

To maximize the crane's tipping fulcrum distance and increase rated lifting capacity

Answer

To level the crane automatically

Answer

To provide electrical grounding for the crane

Answer

To allow the operator to see the outrigger pads more clearly

Question 5

What does the term 'soil bearing capacity' refer to in the context of crane setup?

Accepted Answer

The maximum load per unit area that a soil can safely support without excessive settlement or shear failure

Answer

The total weight of soil at the job site

Answer

The depth to which outrigger pads must be buried

Answer

The moisture content of the soil at the site

Question 6

OSHA 29 CFR 1926.1402 requires the ground to be firm, drained, and graded before crane use. What additional requirement is stated for supporting surfaces under outriggers?

Accepted Answer

Adequate blocking, cribbing, or pads must be used to prevent settling or shifting of the crane

Answer

Surfaces must be paved with asphalt or concrete

Answer

Ground must be excavated and filled with gravel to 3 feet depth

Answer

Soil tests must be performed by a licensed engineer before every lift

A crawler crane weighs 200,000 pounds and each track pad has a total ground contact area of 2,000 square inches.What is the ground bearing pressure under each track in pounds per square inch (psi)?

A crawler crane weighs 200,000 pounds and each track pad has a total ground contact area of 2,000 square inches.
What is the ground bearing pressure under each track in pounds per square inch (psi)?