What is dynamic loading and give an example occurring during rigging?

• A. A slow, gradual increase in load to the rated capacity.
• B. A static load with no movement.
• C. A sudden peak force from movement or impact; e.g., load jerking during lift, swinging, or sudden stoppage of motion.
• D. The load resting at the hook.

Answer: (C)

Dynamic loading means forces that change rapidly due to motion or a sudden event, producing peak loads that are higher than the steady weight of the load. In rigging this shows up when the load is moved quickly or stops suddenly, causing a shock on the rigging system. For example, when you start lifting, the load has inertia and resists acceleration, so the tension in slings and the hook can spike above the static weight. Swinging or side-to-side movement adds lateral forces as the load moves, and a quick stop of motion can produce a sharp impulse that drives peak forces into the rigging components.

These situations are different from static loading, where the load is simply resting or increasing very slowly without movement. That’s why dynamic loading needs special consideration: equipment must be rated for dynamic shocks, and operators should control acceleration, use tag lines to limit sway, and avoid abrupt stops to prevent dangerous peak forces.