Crane Accidents and Emergencies Causes, Repairs and Prevention

Presented by

Larry Lam ChairmanSoon Chong Tok Technical Director

Portek International Limited 15 March 2007

For enquiries, please email: enquiry@portek.comThe contents of this document are copyrighted and proprietary, and may not be reproduced without the permission of Portek International Limited

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