A Review of Recent Tower Crane
Accidents and the Lessons
Learned
Tim Watson
Tim Watson Consulting Limited
TWC
Tower Crane Accidents
130 Accidents Worldwide 1989 2012
Only Major Accidents Considered
Significant structural damage
Collapse of the crane
Top Slew Tower Cranes
Some Self-erecting Tower Cranes
Not: Mobile Cranes
Tracked Crawler Cranes
Dockyard Cranes Gantry Cranes & Container
Cranes
TWC
Tower Crane Accidents
Sources: Internet
o Trade press websites such as International
Cranes
o Private websites such as craneaccidents.com
o Local news websites
HSE Report -Tower Crane Incidents
Worldwide
Personal knowledge
TWC
Limitations
No single source of accurate information
Not all incidents reported on all sites
Trade press websites good for initial reports and follow
up where they can
Private websites can be inconsistent with trade websites
and often speculate on causes
Not all the websites have knowledge of all the incidents.
Some incidents are given on one website but not another.
Local media usually reports in the immediate aftermath of
the incident and details can be vague & inaccurate
Geographic locations. Remote countries with less
developed health & safety cultures tend not to be as well
reported as in the U.S.A. & Europe
TWC
2012
14
2011
15
2010
21
2009
20
2008
2007
2006
10
2005
2004
2003
2002
2001
2000
1999
1989
Number of Accidents
Accidents by Year
25
21
18
13
(10)
9
7
Year
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Numbers of Accidents by Country
Country
No.
Deaths Deaths/
Accident
Country
No.
Deaths
Deaths/
Accident
China
23
55
2.4
Australia
USA
13
15
1.2
UAE
UK
10
0.8
Bahrain
1.3
Singapore
0.71
Vietnam
1.3
Malaysia
Israel
Russia
11
2.2
South Africa
Germany
Canada
0.3
Netherlands
0.8
Malta
India
1.75
Switzerland
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Numbers of Accidents by Country
Country
No.
Deaths
Deaths/
Accident
Taiwan
3.5
Poland
Spain
Ireland
Country
No.
Deaths
Deaths/
Accident
Indonesia
0.5
Japan
0.5
South Korea
Argentina
Philippines
Brazil
Thailand
Czechoslova
kia
Romania
Jordan
Syria
New Zealand
Norway
Saudi Arabia
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Service Condition
22
46
In Service (35%)
Out of Service (11%)
Erection (10%)
17
Dismantling (14%)
Climbing (17%)
Unknown (17)
18
14
13
TWC
Failure Area
22
23
Jib Collapse (17%)
Luffing Jib Collapse (8)
10
Crane Collapse (19%)
14
Crane top collapse (6%)
Slew Ring Failure (5%)
Base Failure (16%)
25
21
Mast Failure (11%)
Unknown (18%)
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Identified Cause
19
Mechanical, Electrical
or Structural (15%)
19
Environmental (15%)
Human Factors (17%)
70
Unknown (54%)
22
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Examples of Accidents
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Environment
Liverpool - January 2007
Luffing tower crane
3 years old
CE marked
DOC to EN 14439
Crane was in use
Light load
Close to minimum radius
Wind near maximum inservice limit
Jib fell backwards across
the site during a lifting
operation
1 Construction worker
killed
TWC
Liverpool Investigation Findings
Jib at small angle to the vertical
Wind from the front held the jib up and caused the luffing
rope to go slack
Luffing rope jammed in the sheaves
Operator tried to lower off and paid out rope from the luffing
winch, which looped down the back of the crane
Luffing rope became free allowing the jib to drop until the
slack rope arrested its fall
Large dynamic load caused the jib to fail and the slewing
section and counter jib became detached from the top of the
tower at the slew ring
One of the counterweights fell on a construction worker
causing fatal injuries
Issues:
Crane design standard
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Liverpool Animation
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Human Factors
Worthing February 2005
Two men killed
One seriously injured
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Worthing February 2005
De-rigging prior to
dismantling
The two erectors fatally
injured working on the jib
removing hoist and trolley
ropes
Third Erector had de-torqued
tower bolts on one side of the
mast
Jib was slewed
Slackened bolts failed and
crane collapsed
Crane owner prosecuted and
fined 389,000
for not managing the
dismantling process
effectively
Issues
Training
Planning
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Mechanical Issues
Battersea September 2006
Saddle jib tower crane
Twenty seven years old
Crane had been in use for a
number of weeks after
erection
Bolts in the joint below slew
ring failed through fatigue
Jib fell across site into an
adjacent road
Crane Driver + Member of
public killed
Slew ring bolts had been
replaced in the air, shortly
after erection
Crane had been erected with
too much counterweight
Issues:
Information and Planning
Maintenance
Thorough Examination
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Human Factors and Structural
Seattle November 2006
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Human Factors
Seattle November 2006
Official enquiry
blamed inadequate
design of foundation
Fatigue failure
Lack of maintenance
and inspection
Issues:
Planning
Base design
Maintenance
Thorough examination
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Human Factors
Croydon June 2007
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Croydon June 2007
Climbing team had not
used the equipment before
and had not had any
specific training on its use
Crane owner fined
100,000 + 33,196 costs
Issues
Training
Planning
Not following
manufacturers
instructions
TWC
Structural
New York March 2008
Luffing Jib Tower Crane
7 Fatalities
Tie collar being attached
Fabric lifting sling failed,
causing tie to fall
Top of crane demolished
building two blocks away
Issues
Planning
Selection of equipment
TWC
New York March 2008
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Human Factors
Miami March 2008
Libeherr luffing jib
crane
Climbing operation
Tower section fell
2 Fatalities
Issues: Planning
Selection of equipment
TWC
Miami March 2008
TWC
Human Factors/Structural
New York May 2008
24 years old Kodiak luffing
tower crane
In-service but not lifting
2 Fatalities
Slew ring support failed
Had been repaired in China
Issues: Maintenance
Thorough examination
TWC
Human Factors/Structural
Liverpool July 2009
Luffing jib crane
Lifting a light load at a
small radius
Witnesses reported
hearing two loud bangs
Tower crane collapsed
onto an adjacent apartment
building
Counterweights fell
through roof
Operator fell out of cab and
through hole in roof
TWC
Liverpool July 2009
TWC
Liverpool July 2009
Base Designer had no
previous experience of
designing this type of
foundation
Principal Contractors
employees had no previous
experience of building this
type of foundation
Contractor fined 280,000
($450,000) (350,000)
Designer went into
administration
Issues:
Poor design
Poor construction
Lack of experience
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Human Factors/Electrical
Rotterdam July 2008
Lifting a heavy load (balcony
slab) within its rated
capacity close to the mast.
Slewed and trolleyed to near
maximum radius for the load
Trolley stationary and held
on mechanical brake
The jib and mast had
deflected under load
Trolley control operated to
bring trolley in before final
positioning
Instead of moving towards
the mast the load ran away
to the outer end of the jib
Crane was overloaded and
the mast failed just above
the a transition section
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Rotterdam July 2008
Trolley winch travel motor
control system was a
PLC/Inverter electronic
system
The incident was attributed
to settings of the control
system
When the trolley control was
operated the trolley motor
mechanical brake was
released before the motor
had built up sufficient torque
to hold the load against the
downward slope of the crane
jib
Issues:-
Poor design
Inadequate hazard analysis
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Guidance on Dealing with the Issues
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EN14439
CEN TC147/WG12
working on a
revision: Use of EN 13001
Use of EN 13849
Requirements for
luffing jib cranes
Interfaces for anticollision systems
Consideration of
powered access to the
operators cab
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Guidance
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Guidance
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Guidance
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Guidance
TWC
Guidance
TWC
All Construction Plant-hire Association
(CPA) Guidance Documents can be
downloaded free at
http://www.cpa.uk.net/p/Safety-Leaflets
TWC
Thank You
TWC
