Raising counterweights to lift loads beyond chart capacities can cause what?

Raising counterweights to lift loads beyond chart capacities can cause what?

• A. Decreases the risk of tipping
• B. Can increase structural loads to the point of collapse
• C. Reduces crane reach
• D. Improves operator visibility

Answer: (B)

The main idea is that lifting beyond what the crane’s capacity chart allows pushes the entire system into stresses it wasn’t designed to handle. The capacity chart is a balance of forces: the hoisted load, the boom position, and the counterweight that keeps the crane stable. When you raise counterweights beyond what the chart assumes for a given configuration, you change the force distribution and increase the base and structural member reactions. That means bending moments, axial forces, and connection stresses in the crane’s structure can exceed their design limits, potentially causing deformation, failure, or even collapse. So, increasing counterweights to try to lift heavier loads than the chart permits risks overloading the crane’s structure rather than improving stability—hence the danger of reaching the point of structural collapse. The other options don’t reflect how counterweights influence the forces within the crane (they don’t inherently reduce tipping risk, don’t change reach, and don’t improve visibility).

The main idea is that lifting beyond what the crane’s capacity chart allows pushes the entire system into stresses it wasn’t designed to handle. The capacity chart is a balance of forces: the hoisted load, the boom position, and the counterweight that keeps the crane stable. When you raise counterweights beyond what the chart assumes for a given configuration, you change the force distribution and increase the base and structural member reactions. That means bending moments, axial forces, and connection stresses in the crane’s structure can exceed their design limits, potentially causing deformation, failure, or even collapse.

So, increasing counterweights to try to lift heavier loads than the chart permits risks overloading the crane’s structure rather than improving stability—hence the danger of reaching the point of structural collapse. The other options don’t reflect how counterweights influence the forces within the crane (they don’t inherently reduce tipping risk, don’t change reach, and don’t improve visibility).