Uncovering the Root Causes of Crane Accidents

Klaus MeissnerDirector Product Strategy, Terex Cranes

Root Causes of Accidents with Mobile Cranes

• Why talking about Root Causes?

• Technical Topics vs Behavioral Issues

• More Sensors = higher Level of Safety?

• Is “Hope” really a Business Principle?

1st Accident by overload, 2nd Accident (this picture) due to improper repair

Underestimating the wind load on “light loads with large sail areas”

Austria – crane out of service, wind from the front, excessive damage, insurance (?)

Sweden, broken Slings, damages only

Norway, unknown load, outrigger forces exceed ground bearing capacity

USA, 4 Cranes lifting one load, CoG unclear, overloading one crane

Traveling at night on soft ground, Derrick Ballast grounded, crane pulled over, damages

Sweden, incorrect maintenance of hoist rope, no test lift during man basket use, 2 fatalities

The Netherlands, wind on load, boom pushed back, damages

Crane Accidents – Root Causes

Crane Accidents – Root Causes

Crane Accidents – Root Causes

Crane Accidents – Root Causes

Proper Repair and Maintenance

Mexico, insufficient inspection and maintenance, 1 fatality

/IKEA instruction manual/

Crane Accidents – Correct Assembly

… is such incident avoidable by advanced controls systems?

More Sensors =

higher Level of Safety?

… how much control do we want/accept?

Risk =

Likelihood of Occurrencemultiplied by

Amount of Exposure/Cost

… this is where human behavior

comes into the picture

Men Machine Interface – The human factor

Crane Accidents – Root Causes

UK, RCL setting wrong, damage only

Italy, RCL setting wrong, 1 fatality

Failure to Plan is

Planning for Failure

Spain, change of plan, grounded SL-CWT pulls mast over, 1 fatality

PLAN: Develop a Plan DO: Act according to PlanCHECK: Are Conditions as per Plan?ACT: …Take Action if needed

3.18 mobile crane• self powered jib crane capable of traveling loaded or

unloaded without the need for fixed runways and relying on gravity for stability. /…/

• NOTE 1Mobile cranes can operate on tires, crawlers or with other mobile arrangements. In fixed positions they can be supported by outriggers or other accessories increasing their stability. /…/

Gravity for Safety

Ground & Center of Gravity

Angle of ReposeLET`S MAKE SOME

EXPERIMENTS

Symmetrical Loading Symmetrical Loading to the Front

Non-Symmetrical Loading

Top View on Crawler car Body, Crawlers turned to better indicate Shape

Symbol indicates Centre of Gravity

Symbols indicate Ground Pressure under Crawler

Traveling on site, unsymmetrical setup of crawlers, damages

Traveling onto mats, shifting load distribution, moving CoG, damages

Traveling on site, high loading, ground gives way, 5 fatalities

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