Tower Crane Erection, Climbing, and Dismantling 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 Tower Crane Erection, Climbing, and Dismantling flashcards as text
What is the function of internal ties (anchor ties) on a tower crane?
Answer: Internal ties anchor the crane mast to the adjacent building structure to provide lateral support above the free-standing height
Internal ties (anchor ties) are structural connections between the tower crane mast and the adjacent building frame that provide lateral support to allow the crane to be erected above its maximum free-standing height.
What is the sequence for removing internal ties during tower crane dismantling?
Answer: Ties must be removed from the top down, starting with the highest tie first as the crane is shortened
During dismantling, internal ties must be removed from the top down: the highest tie is removed first as the crane is shortened from the top, ensuring the remaining mast height never exceeds the free-standing limit.
What pre-climbing inspection must be performed before a tower crane top-climbing operation?
Answer: A comprehensive inspection of the climbing frame, hydraulic cylinders, mast section connections, and all safety devices must be completed by a qualified person
A thorough pre-climbing inspection by a qualified person must verify the climbing frame integrity, hydraulic cylinder condition, mast connection pins, and all safety locks before any climbing operation begins.
What is the purpose of the anti-fall device (or climbing frame safety lock) during tower crane climbing operations?
Answer: To prevent the climbing frame from falling if hydraulic pressure is lost during the jacking operation
The anti-fall device (safety lock or ratchet mechanism) engages with the mast to prevent the climbing frame from descending if hydraulic pressure fails during the jacking stroke, acting as a mechanical backup.
What is the maximum allowable out-of-plumb tolerance for a tower crane mast during erection?
Answer: Typically 1:500 (0.2%) of the mast height, or as specified by the manufacturer
Tower crane masts must be erected plumb within very tight tolerances, typically 1:500 (0.2% of height) as specified by the manufacturer, because out-of-plumb creates eccentricity that amplifies bending moments in the mast.
What is required before a newly erected or climbed tower crane is put into service?
Answer: A post-erection or post-climbing inspection and load test by a qualified person, with documentation, before the crane is placed in service
OSHA and ASME standards require a post-erection inspection and functional test (and often a load test) by a qualified person, with documentation, before the crane is authorized for production use.