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Crane Accidents and Emergencies – Causes, Repairs, and
Crane Accidents and Emergencies Causes, Repairs and Prevention Presented by Portek International Limited 15 March 2007 Larry Lam Soon Chong Tok Chairman Technical Director For enquiries, please email: [email protected] The contents of this document are copyrighted and proprietary, and may not be reproduced without the permission of Portek International Limited Definitions A Crane Accident is an unplanned and unintentional event involving a crane or cranes, or other objects that result in damage or injury of some kind and normally involves a strong human element in its causation. A Crane Emergency situation is an unexpected and sudden event in which the crane is subject to damage, and where the cause is not immediately linked to the operator. A Crane Incident is a general term for either a crane accident or emergency Crane Accidents can happen in the following ways: when a ship contacts a crane when a crane contacts a ship when cranes contact each other due to strong wind gusts during operation, often resulting in a multiple chain collision when a crane contacts another crane or an object during operation Crane Accidents Right seaside leg hit diagonally by ship's bow (ship contacts crane) Crane Accidents Crane boom struck ship’s funnel (crane contacts ship) Crane Accidents Crane (blown by wind gusts) collapsed after collision Crane emergency situations can arise from Exceptional situation such as typhoons, hurricanes, earthquakes resulting in crane collapse, derailment or severe damage Crane failure as in electrical fires in diesel generator or electrical room crane drive faults leading to free fall of load mechanical faults as in brake failure, twist-locks failures, etc resulting in uncontrolled fall of load structural damage as in fatigue failure, poor workmanship or design. Heavy weather or inadequate lashing during ocean transportation of cranes Crane emergency situations Structural failure - A-frame pylon bent and tipped forward Crane emergency situations Right tension rod broke from fatigue Frequency of Crane Incidents Crane Incidents are happening with increasing frequencies, due to: rapidly increasing population of cranes increasing crane dimensions, hence decreasing visibility and control insufficient distance between fender face and seaside rail, and increasing flare of ship’s bow, as ships get bigger standards of crane maintenance not keeping up standards of safety in crane operation and terminal operation failing to keep up insufficient understanding of risks involved, and lack of precautions taken adverse and unpredictable weather Typical Processes in a Crane Incident Recovery phase comprising Survey and Salvage and Stabilization Repairs and Re-commissioning Typical damage bending and buckling of the legs, sill beams and portal beams derailment seaside and landside bogies tearing apart of joints between equalizer beam and sill beam Typical damage Ship contacting Crane boom Damage from Ship contacting crane Typical damage Contact at seaside leg, only a nick is seen Typical damage Derailment at seaside Typical damage No derailment landside, but severe damage to leg Typical damage Severe bending of landside leg Typical damage Buckling of sill beam landside Typical damage Joint at equalizer beam separated and twisted Typical damage Total destruction of boom snagged by a departing ship Typical damage Entire portal and boom twisted by ship pulling on boom Typical damage Wind gusts causing crane collisions Damage from Collisions Repairs Design and Analysis Fatigue failure of an unloader & computer modeling of crane structure Repairs Simulation of failure & Redesign and Repairs Crane Supports for Repairs Computer simulation of crane support Crane Supports for Repairs Robust support in place before cutting Repair Methodology Damaged plate removed and replaced Repair Methodology Damaged sill beam cut away Repair Methodology Replaced with new sill beam Repair Methodology Heavy damage due to constraints to side way displacement Repair Methodology Derailment allows displacement, therefore little or no damage Repair Methodology Structural bolts may be weakened and need replacement Repair Methodology Floating crane removing boom for repairs Repair Methodology Re-installing repaired boom Repair Methodology Boom hinge inspection and NDT checks Repair Methodology Line boring of boom hinge Repair Methodology Dimensional checks using theodolite equipment Prevention Prevention of crane incidents at different levels: at crane design and engineering level, at crane operating level, at terminal operation level Prevention at crane design level Double brake machinery Prevention at crane design level Caliper brakes on flanges of boom hoist drums Prevention at crane design level Thruster disc brake for gantry instead of motor-mounted multi-disk brake Prevention at crane design level Caliper brakes on gantry wheel – To provide even more braking power Prevention at the crane operating level Safety training of operator cannot be overemphasized. Emergency drills “Boom down” is an open invitation to trouble Prevention at the terminal operating level Berthing and un-berthing - Vessels should come alongside quay as parallel as possible. Equipment maintenance not to be compromised in favour of operational expediency Risk Management Plan • Terminate the risks – not likely. Inherently risky. • Transfer the risks - Insurance Policy. Consequential losses not covered • Tolerate the risks – Accepting the risks. Self insurance • Treating the risks involves prevention, reducing the likelihood of occurrence and severity of loss Conclusion Risks associated with container cranes will increase, due to Increasing probability of occurrence Greater severity of loss. Modern container quay cranes quantum leap in size, and complexity, not yet fully understood as to risk factors Thank You
