NCCCO Ground Bearing Pressure and Outrigger Setup 4

Question 1

Which soil condition would have the LOWEST allowable ground bearing capacity?

Accepted Answer

Soft wet clay

Answer

Soft wet clay has very low shear strength and allowable bearing capacity, often less than 1,000 psf compared to thousands of psf for compacted granular soils.

Question 2

What is the function of a load cell or outrigger force indicator when used during crane operations?

Accepted Answer

It provides real-time measurement of the actual load on each outrigger

Answer

Load cells at outrigger pads measure actual outrigger reaction forces, allowing comparison against the soil's allowable bearing capacity.

Question 3

A crane is operating near an excavation. How does the proximity to the excavation affect outrigger placement?

Accepted Answer

Outriggers placed too close to an excavation edge can cause slope failure or cave-in

Answer

Concentrated outrigger loads near an excavation slope can exceed the soil's shear strength and trigger a slope failure or wall collapse.

Question 4

Which document would provide the best engineering data on allowable ground bearing pressure for a specific crane setup on a construction site?

Accepted Answer

A geotechnical or soil investigation report for the site

Answer

A site-specific geotechnical report provides measured soil bearing capacity data from borings or tests, giving the most accurate and reliable values.

Question 5

What effect does increasing the size of an outrigger float pad have on ground bearing pressure?

Accepted Answer

It decreases ground bearing pressure by spreading the load over more area

Answer

A larger pad area distributes the same outrigger force over more square footage, reducing the pounds per square foot of pressure applied to the soil.

NCCCO (National Commission for the Certification of Crane Operators) Practice Test

NCCCO (National Commission for the Certification of Crane Operators) Practice Test

NCCCO Ground Bearing Pressure and Outrigger Setup 4