Dynamic Loading and Environmental Effects Flashcards
6 cards from real NCCCO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Dynamic Loading and Environmental Effects flashcards as text
What is the 'sail effect' and how does it impact lifting operations?
Answer: Large, flat loads catching wind like a sail, dramatically increasing the force on the crane
Large flat loads (steel sheets, panels, containers) present significant wind resistance. Even moderate wind can create forces that exceed the crane's capacity when lifting high-sail-area loads.
How does rain affect crane operations?
Answer: Rain reduces visibility, makes surfaces slippery, adds weight to loads, and can affect electrical systems
Rain reduces visibility, creates slippery conditions on crane surfaces and ground, adds weight to absorbent loads, and can cause electrical hazards. Operations may need to be modified.
What causes 'shock loading' on a crane?
Answer: Sudden application of force, such as jerking a stuck load free or catching a falling load
Shock loading occurs when forces are applied suddenly rather than gradually. Examples include jerking a load to break it loose, sudden braking, or catching a falling load. These forces can be many times the static load.
What precaution should be taken when operating a crane near the ocean or in coastal areas?
Answer: Account for salt air corrosion, stronger/gustier winds, and potentially unstable sandy ground conditions
Coastal operations present unique challenges: salt spray accelerates corrosion, coastal winds are typically stronger and more variable, and sandy or saturated ground may not support crane loads.
How does temperature affect the crane's load chart ratings?
Answer: Extreme heat can reduce hydraulic system efficiency and steel strength; extreme cold increases brittleness risk
Temperature extremes affect crane performance: heat reduces hydraulic fluid viscosity and steel yield strength; cold increases brittleness risk and thickens fluids. Some manufacturers provide temperature-adjusted ratings.
What is the effect of hoisting speed on dynamic loading?
Answer: Faster hoisting increases dynamic forces, especially when starting or stopping
Rapid acceleration or deceleration of the hoist creates inertial forces that add to the static load. Smooth, controlled movements minimize dynamic loading.