FREE NCCCO Principles of Crane Stability and Structural Integrity Questions and Answers

Question 1

On a mobile crane load chart, capacities listed above a bold line or marked with an asterisk (*) are typically based on what?

Accepted Answer

The crane's structural integrity.

Answer

The crane's stability against tipping.

Answer

The wire rope's breaking strength.

Answer

The engine's hydraulic power.

Question 2

How does increasing the load radius affect a crane's rated capacity?

Accepted Answer

It decreases the capacity.

Answer

It increases the capacity.

Answer

It has no effect on the capacity.

Answer

It only affects capacity when the boom is short.

Question 3

What is the 'tipping axis' or 'fulcrum' of a crawler crane?

Accepted Answer

The edge of the crawler tracks.

Answer

The center pin of the crane.

Answer

The top of the counterweight.

Answer

The boom hinge pins.

Question 4

A crane's stability is greatest when its center of gravity is:

Accepted Answer

As low as possible and near the center of rotation.

Answer

As high as possible.

Answer

Directly over the tipping axis.

Answer

As far from the load as possible.

Question 5

What is the most critical factor for ensuring maximum stability when setting up a crane on outriggers?

Accepted Answer

Making sure the outriggers are on firm, level ground.

Answer

Ensuring the tires are inflated to the correct pressure.

Answer

Using the largest possible hook block.

Answer

Parking the crane facing downhill.

Question 6

When a crane is 'on rubber' (not on outriggers), its capacity is generally much lower because:

Accepted Answer

The tipping axis is narrower and the suspension allows movement.

Answer

The tires might go flat.

Answer

The engine provides less power when stationary.

Answer

The brakes are not strong enough to hold the load.

Question 7

Backward stability of a crane is most at risk when:

Accepted Answer

Using a long boom at a high angle with no load.

Answer

Lifting a heavy load at a short radius.

Answer

Traveling with a load.

Answer

Swinging the load over the side.