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

The ground bearing pressure is greatest over the corner of a crawler crane due to the distribution of weight and the mechanics of the crane's structure. Crawler cranes have a wide footprint that helps distribute their weight across a larger area, but the weight concentration will naturally be highest at the corners of the tracks. This is particularly evident when the crane is in operation and under load, as the load acting through the boom raises the pressure at the points where the tracks contact the ground, especially at the corners where the weight is not as effectively distributed.

In scenarios when the crane is lifting or moving loads, the center of gravity shifts towards the boom and load, amplifying the forces exerted near the edges or corners of the tracks. The design of crawler cranes, including the way they are engineered to maintain stability, means that understanding this pressure distribution is crucial for ensuring safe operations and preventing ground failure or tipping.

While the other options may seem plausible based on their descriptions, they do not accurately reflect the mechanics involved in load distribution on a crawler crane. For example, the center of the crane may have a less concentrated force due to how the weight is spread, and both the rear and midpoint of the tracks do not concentrate the bearing pressure as effectively as the corners do