Tower Crane Inspection

A tower crane fails differently from other cranes. It stands for months or years, it is assembled and extended on site rather than delivered complete, and when it collapses it takes down whatever is beneath it. Most tower crane incidents occur during erection, climbing or dismantling — the phases when the structure is temporarily incomplete — not during routine lifting.

Foundation and base

• Verification that the foundation as constructed matches the design the crane manufacturer requires for that machine and configuration
• Anchor and holding-down bolt condition, torque and grout, and the fixing angle assemblies
• Base frame or cruciform ballast, correct mass and placement against the manufacturer's requirement
• Levelness of the base within the tolerance the manufacturer specifies, since out-of-plumb error multiplies with mast height
• Ground bearing conditions, drainage and evidence of settlement
• Rail track condition, gauge, level and end stops on travelling cranes

Pre-erection component inspection

Components are examined before they leave the ground, because a cracked mast section or a worn pin discovered at height is a far more expensive problem.

• Mast sections examined for distortion, weld cracking at the chord-to-lacing joints, corrosion and previous repair
• Pins, bushes and retention devices for wear, ovality and correct grade
• Jib and counter-jib sections, tie bars and pendant condition
• Slewing ring, bolt condition and correct grade of fasteners
• Hoist, slew, trolley and luffing mechanisms, gearboxes and brakes
• Wire ropes assessed against ISO 4309 discard criteria before installation
• Documentation review — manufacturer's manual, previous inspection records, repair history and modification approvals

Erection, climbing and dismantling

These are the highest-risk phases and they are inspected as staged operations rather than as a single event.

• ErectionVerification that assembly follows the manufacturer's sequence, that bolt torques are applied and recorded, that the mast is plumb within tolerance, and that the configuration erected matches the configuration the foundation was designed for.
• ClimbingInspection of the climbing frame and its engagement, hydraulic system condition, the balance condition required during the climb, and verification that the crane is correctly reconfigured and re-secured at each new height.
• Tie-ins and anchoragesWhere the crane is tied to the structure, verification that ties are installed at the spacing and positions the manufacturer requires, that the fixings into the structure are adequate, and that the structure itself can take the reaction.
• DismantlingInspection before and during dismantling, including confirmation that the crane is in a condition to be dismantled safely and that the sequence reverses erection correctly.

Periodic inspection of standing cranes

• Structural examination of mast, jib, counter-jib, tower head and turntable for cracking, distortion and corrosion
• Slewing ring bolt torque check and tilt or rock measurement for bearing wear
• Mast bolt torque verification at sampled connections, and full check after any climb
• Counterweight condition, correct mass and secure retention
• Hoist, trolley and slew mechanisms, brakes tested for holding capability
• Wire rope, reeving, drum spooling, dead turns and terminations
• Hook condition, throat opening, latch and swivel
• Limit switches — hoist, trolley, slew and luffing — function tested
• Load moment indicator and overload protection checked against known loads and radii
• Anemometer function and the wind speed at which operation must stop
• Access ladders, rest platforms, fall arrest systems and cage condition
• Electrical supply, earthing, lightning protection and cabling
• Cab condition, controls, emergency stop and evacuation arrangements

Out of service condition

A tower crane spends most of its life not lifting, and the out-of-service arrangements determine what happens in high wind. We verify that the crane can weathervane freely, that the slew brake is released as the manufacturer requires, that the trolley and hook are in the specified parked position, and that the procedure for securing the crane is documented and understood by the operator rather than assumed.

Standards applied

Inspection follows the standard specified by your contract or the governing authority, most commonly ASME B30.3 for tower cranes, EN 14439 where the machine is CE marked, ISO 9927-3 for tower crane inspection, ISO 4309 for wire rope, and BS 7121 Part 5 for the safe use of tower cranes where the client works to British practice. The manufacturer's erection manual and inspection schedule are applied alongside, since they set the torques, tolerances and sequences no general standard can specify.

Load testing

Proof load testing is carried out on erection, after structural repair or modification, after each climb where the specification requires it, and at the intervals set by the governing authority. Loads are applied at the radii that matter for the crane's duty, with overload protection, brakes and limit devices verified, and the structure examined after the test.

When inspection is required

• Before erection, on the foundation and the components
• On completion of erection, before the crane is released for use
• After each climb or change of configuration
• At the periodic interval set by the governing authority
• After high wind, an overload event, contact with the structure, or any incident
• Following structural or weld repair
• Before dismantling
• Before hire out, or on acceptance of a hired machine

Accreditation and approvals

ITMAD is accredited to ISO/IEC 17020 as an inspection body, is an ADNOC approved inspection contractor, and is listed on the Abu Dhabi City Municipality register of Approved Third Party Inspection Bodies — the approval Abu Dhabi clients verify before accepting a crane inspection certificate. Attendance is arranged around the erection or climbing programme rather than office hours.

What you receive

• An inspection certificate in the format the governing authority requires
• A report identifying the crane by make, model, serial number, configuration and height
• Foundation and tie-in verification records where those stages were inspected
• Bolt torque records at the connections checked
• Findings recorded component by component with photographic evidence
• Defects classified by severity, separating what stops the crane from what must be monitored
• Load test results with applied load, radius and post-test condition
• Your equipment register updated, where we hold it