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

What effect does moving a crawler crane from soft ground to harder ground have on ground bearing pressure?

1. It increases

2. It decreases by a third

3. It remains the same

4. It decreases by half

The correct answer is: It increases

When a crawler crane is moved from soft ground to harder ground, the ground bearing pressure typically increases. This is because the crane's weight is distributed over a smaller area when placed on a more stable surface. Soft ground tends to deform under the weight of heavy equipment, allowing for more settling and spreading out of the load. Conversely, harder ground provides less deformation, which results in a more compacted area directly beneath the crane's tracks. As the crane's weight remains constant but is concentrated over a more solid base, the pressure exerted on that ground increases. This increase in ground bearing pressure is a critical consideration for crane operators, as it affects the stability of the crane and the risk of ground failure.