NCCCO Tower Crane case studies
NCCCO Tower Crane · Put your knowledge to work in context.
The CCO Tower Crane Operator certification is a nationally recognized, internationally accredited credential administered by the National Commission for the Certification of Crane Operators (NCCCO). It is intended for operators who run tower cranes on construction, steel erection, utility, crane rental, petrochemical, pulp and paper, and related projects, and it was developed by a task force of operators, trainers, managers, supervisors, and manufacturers drawn from across the crane industry. The NCCCO Tower Crane case studies are 5 cases and about 3,715 words.
1Foundation Bearing Shortfall and an Open Excavation at the Crane Base
A 55 m jib tower crane will be erected on a fixed base on a new 6.0 m × 6.0 m × 1.4 m reinforced concrete foundation. The manual requires 200 kPa foundation bearing and the base level to 1:500.
716 words, about 4 min2Climbing Sequence Interrupted: Wind, Roller Gap and Wrong Counterweight
An internal climbing tower crane is being climbed inside a concrete core from level 8 to level 10 on its hydraulic climbing frame. The manual's climbing procedure requires the jib to be balanced per the configuration table, the guide rollers set to 3 mm ± 1 mm, and the climbing frame to carry the crane's weight at about 150 bar before the mast support is released.
702 words, about 4 min3Chart Reading, Reeving and Sling Angle on a Near-Capacity Pick
60 m jib tower crane. The cab chart page reads (capacities include the hook block and trolley, tonnes): Radius 2-fall 4-fall --- --- --- 28 m 5.6 6.9 32 m 4.8 5.4 36 m 4.1 4.4 Deduct the weight of everything below the hook.
750 words, about 4 min4Blind Landing, Lost Signal and a Shock Load on the Jib
Concrete placing on a 14-storey frame with a 1.2 m³ skip (0.35 t empty, about 3.2 t full). The operator in the cab can see the hoist path but not the landing point on level 12, which is behind a stop-log.
774 words, about 4 min5Weekly Inspection Findings: What Stops the Crane and Who Clears It
Weekly inspection of a three-year-old 60 m jib tower crane working two shifts. Findings: (a) the hoist rope, 16 mm 6×36 IWRC, has six broken wires in one lay within a 30 × d length and a birdcage about 4 m from the dead end; (b) the hoist limit switch lever is cable-tied out of the way because it 'kept tripping'; (c) two slew ring bolts below the cab have no torque stripe and rust is weeping from the joint; (d) the anemometer cups are seized and the wind readout shows 0 m/s while the site flags are stiff; (e) the third-party thorough examination certificate on file is dated 13 months ago and the crane has worked continuously since; (f) the chart in the cab is for a 55 m jib.
773 words, about 4 min