Question 1

According to OSHA, outriggers must be extended:

Accepted Answer

Outriggers must be set according to the load chart being used (e.g., fully extended) and the tires must be relieved of all weight.

Question 2

Blocking (cribbing) placed under outrigger pads must be:

Accepted Answer

Blocking must be sufficient to support the load without failure and distribute the weight over a large enough area to prevent sinking.

Question 3

When setting up a crane near an excavation, the minimum distance from the edge should be:

Accepted Answer

A general rule of thumb (and often required) is a 1:1 ratio—stay back 1 foot for every 1 foot of depth to prevent trench collapse.

Question 4

What is the maximum allowable level error for a mobile crane to maintain valid load chart ratings?

Accepted Answer

ASME B30.5 requires the crane to be level within 1%. Exceeding this drastically reduces capacity due to side loading.

Question 5

The 'Axis of Rotation' is:

Accepted Answer

The axis of rotation is the vertical center point of the turntable bearing, from which operating radius is measured.

Question 6

If a crane is set up out of level by 3 degrees, the effective capacity can be reduced by as much as:

Accepted Answer

A 3-degree slope can reduce capacity by up to 50% on long booms due to the increased radius and side-loading forces.

Question 7

Proper blocking under outrigger floats should be:

Accepted Answer

Blocking timbers must be tight together with no gaps to create a solid structural platform.

Question 8

When extending outriggers, you should always:

Accepted Answer

You must extend the horizontal beams fully (or to pinned position) before lowering the vertical jacks to lift the crane.

Question 9

Ideally, the crane should be leveled by:

Accepted Answer

Raise the low side to level. A level should be placed on the upper revolving frame (turntable) or checked via the bubble level in the cab.

Question 10

Using a 'Fifth Front Outrigger' (stabilizer) on a truck crane allows:

Accepted Answer

Without a front stabilizer, truck cranes usually have no capacity over the front. The fifth outrigger provides the necessary stability point.

Question 11

If the ground is soft, you should:

Accepted Answer

Increasing the bearing area reduces the ground pressure (PSI) to match what the soft soil can support.

Question 12

Who is responsible for ensuring the ground conditions are adequate for the crane?

Accepted Answer

OSHA 1926.1402 places the responsibility on the Controlling Entity to ensure ground conditions are firm, drained, and graded.

Question 13

The load applied to the ground by the outrigger pad is greatest when:

Accepted Answer

Lifting over the corner concentrates the crane's weight and the load onto a single outrigger, creating the maximum ground pressure.

Question 14

Timber blocking must be:

Accepted Answer

Blocking must extend beyond the edges of the outrigger pad to effectively distribute the load.

Question 15

When assembling a lattice boom on the ground, the boom sections should be supported by blocking to prevent:

Accepted Answer

Blocking prevents the boom structure (cords) from bending or damaging diagonals against the ground.

Question 16

Boom suspension system pendants should be:

Accepted Answer

Pendants must be matched pairs of equal length to ensure the boom is not twisted.

Question 17

When installing boom pins, the pin should be driven:

Accepted Answer

Pins are typically driven from the outside in so the keeper pins are accessible and safe to install.

Question 18

Extending the crawler tracks (if extendable) increases:

Accepted Answer

Widening the stance (extending tracks) increases the tipping axis distance, improving stability and capacity.

Question 19

Before lifting a load on outriggers, the tires must be:

Accepted Answer

To achieve the rated stiffness and stability of the 'On Outriggers' chart, the tires must not support any weight.

Question 20

Counterweights must be installed:

Accepted Answer

Improper installation sequence can cause the crane to tip backward or fail structurally.

Question 21

If a crane's bubble level is centered, the crane is level to within approximately:

Accepted Answer

Target bubbles typically indicate a levelness of 1% or better when centered.

Question 22

The term 'cribbing' refers to:

Accepted Answer

Cribbing is the layering of timbers to create a support base.

Question 23

When setting up near a cellar wall or basement, the pressure from the outrigger travels through the soil at a ___ angle.

Accepted Answer

Load spreads at roughly a 45-degree angle. Setup must ensure this zone of influence does not hit the basement wall.

Question 24

Span blocking (bridging) is used to:

Accepted Answer

Span blocking allows the outrigger load to be supported on solid ground on either side of a weak spot.

Question 25

A lattice boom should never be lowered below horizontal without:

Accepted Answer

Depending on the crane geometry (gantry/mast height), lowering the boom too far can cause the suspension system to go into compression or the crane to tip backward.

Question 26

Before leaving the crane unattended, the operator must:

Accepted Answer

OSHA 1926.1417 prohibits leaving a load suspended unattended. The crane must be secured.

Question 27

When determining the proper setup location, the operator must check for:

Accepted Answer

These are the three primary site hazards that dictate setup.

Question 28

On a crawler crane, 'retractable' side frames allow:

Accepted Answer

Side frames extend for stability during lifting and retract to reduce width for transport.

Question 29

The term 'Forward Stability' refers to the crane's resistance to:

Accepted Answer

Forward stability is tipping in the direction of the boom/load.

Question 30

Backward stability is most critical when:

Accepted Answer

With no load and the boom high, the center of gravity shifts rearward toward the counterweight, creating the highest risk of backward tipping.

Question 31

What is the purpose of 'Gantry' or 'Live Mast' on a lattice crane?

Accepted Answer

The gantry increases the angle of the boom hoist ropes relative to the boom, providing better mechanical advantage to lift the boom.

Question 32

Blocking mats should be bolted together to:

Accepted Answer

Bolted mats act as a single unit, preventing individual timbers from slipping out under load.

Question 33

If you must set up on a slope, you should:

Accepted Answer

The crane chassis/turntable must be level. Use blocking to build up the low side.

Question 34

When assembling a jib, the jib forestay/backstay pendants must be connected:

Accepted Answer

The pendants support the jib. If you lift the boom without them connected, the jib will hang or collapse.

Question 35

The 'Carbody' of a crawler crane refers to:

Accepted Answer

The carbody is the central lower frame.

Question 36

Rooster sheave (auxiliary boom nose) allows:

Accepted Answer

It separates the whip line from the main block to prevent tangling.

Question 37

When retracting a telescopic boom, the load block will:

Accepted Answer

Retracting the boom shortens the distance to the tip, feeding out rope relative to the tip? Wait. No. Retracting the boom shortens the boom length. The rope length stays same at the drum. The distance from tip to block decreases? No. If you retract, the tip comes closer to the drum. The rope becomes 'slack', so the block lowers. Wait. Let's visualize. Tip moves closer to the base. Rope path shortens. Block lowers.

Question 38

Anti-Two-Block devices must be:

Accepted Answer

A2B devices are critical safety aids and must be functional.

Question 39

If a level indicator is not functioning, the crane:

Accepted Answer

OSHA allows temporary operation if an alternative method (carpenter's level) is used.

Question 40

Outrigger floats (pads) should be secured to the outrigger jacks to:

Accepted Answer

Safety precaution to prevent dropping heavy pads on personnel during setup/stowing.

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