Crane Accidents and Emergencies Causes, Repairs and Prevention
Presented by
Larry Lam ChairmanSoon Chong Tok Technical Director
Portek International Limited 15 March 2007
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DefinitionsA 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 shipwhen 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
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 Accidents
Exceptional situation such as typhoons, hurricanes, earthquakes resulting in crane collapse, derailment or severe damageCrane failure as in
electrical fires in diesel generator or electrical roomcrane drive faults leading to free fall of loadmechanical faults as in brake failure, twist-locks failures, etc resulting in uncontrolled fall of loadstructural damage as in fatigue failure, poor workmanship or design.
Heavy weather or inadequate lashing during ocean transportation of cranes
Crane emergency situations can arise from
Structural failure - A-frame pylon bent and tipped forward
Crane emergency situations
Right tension rod broke from fatigue
Crane emergency situations
Frequency of Crane IncidentsCrane Incidents are happening with increasing frequencies, due to:rapidly increasing population of cranesincreasing crane dimensions, hence decreasing visibility and controlinsufficient distance between fender face and seaside rail, and increasing flare of ship’s bow, as ships get biggerstandards of crane maintenance not keeping up standards of safety in crane operation and terminal operation failing to keep upinsufficient 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 StabilizationRepairs and Re-commissioning
Typical damage
bending and buckling of the legs, sill beams and portal beamsderailment seaside and landside bogies tearing apart of joints between equalizer beam and sill beam
Ship contacting Crane boom
Typical damage
Damage from Ship contacting crane
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
Typical damage
Damage from Collisions
RepairsDesign and Analysis
Fatigue failure of an unloader & computer modeling of crane structure
Simulation of failure & Redesign and Repairs
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
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
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 over-emphasized. 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