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 anchoring system keeps a freestanding tower crane stable?
Answer: The concrete foundation/base and, for taller configurations, tie-ins (braces) to the building structure
Freestanding tower cranes rely on a massive concrete foundation. Above certain heights (determined by the manufacturer), the crane must be 'tied in' — braced to the building structure for additional stability.
During dismantling, in what order are tower crane components typically removed?
Answer: Any convenient order
Dismantling generally starts with the counter-jib and counterweights (to reduce weight at the top), then the jib, then tower sections are removed from the top down. This maintains balance at each step.
What is a 'climbing frame' on a tower crane?
Answer: A hydraulic frame that temporarily supports the crane upper structure during climbing, allowing new tower sections to be inserted
The climbing frame is a specialized hydraulic structure that jacks up the crane's upper works (slewing unit, jib, counter-jib) to create space for a new tower section to be inserted underneath.
Why must tower crane dismantling be completed before high-rise demolition begins?
Answer: The crane relies on building tie-ins for stability; removing building structure before the crane is dismantled or ties are relocated removes the crane's support
Tower crane tie-ins are anchored to the building structure. If the building is demolished before the crane is removed or ties relocated, the crane loses its lateral support and can collapse.
What communication system is essential during tower crane climbing operations?
Answer: Continuous two-way radio communication between the climbing crew, the operator, and the ground supervisor
Continuous radio communication is essential because the climbing crew, operator, and ground personnel must coordinate precisely. Any miscommunication during climbing can cause structural failure.
What is a 'top-slewing' versus a 'bottom-slewing' tower crane?
Answer: Top-slewing rotates above the tower; bottom-slewing rotates at the base
Top-slewing cranes have the slewing mechanism above the tower (the jib and counter-jib rotate at the top). Bottom-slewing cranes rotate at the base, and are typically self-erecting, smaller cranes.