CRANEACCIDENTS
assumptions takenwhen the load
chartwas calculated, or reduce thevalue
of thepermissiblewind speed for the lift.
This important information isneeded
before lifting lightweight loadswith large
sail areas.
The reasonbehindmost turbine
erectionaccidents is insufficient planning
and/or a lackof knowledge, especiallywhen
lifting rotor assemblies. There
have alsobeena lot of accidentswhen
semi-assembled cranes aremoved from
one erection site to thenext.Cranes
can topplewhiledrivingbecauseof an
insufficient loadbearing capabilityof the
road.Most, or at leastmany, roads leading
to turbine erection sites aredesigned for
anaxle loadof 16 tonnesbut,whena large
crane ismoved in the semi-assembled
configuration, axlepressure canbewell
beyond25 tonnes.
Inaddition, toooften it is forgotten
that besides thehigh loads imposedunder
thewheels, the centreof gravity is at a
significant height. Thisheightmight be the
sameor evenmore in comparison to the
support baseof thewheels, or the support
base at the suspension cylinders, in case the
suspensiongivesway.A centreof gravity
severalmetresup in the air for apartially
erected crane isnot unusual. Thehigher
the centreof gravity, themore the crane
reacts to imperfections in the road.When
the centreof gravitymovesover the tipping
line, for example, due tounevenground,
the cranewill tipand there is absolutely
nothingkeeping it from tipping, unless the
outriggers areout and theoutriggerpads
are sliding just above theground.
Manyaccidentshappenduring routine
jobs and,moreoften thannot, noplanning
isdoneprior to the crane arrivingon the
site. Theoperatorhasdone similar jobs
over andover again, and it isherewhere
wehave themajorityof crane accidents.
Wevery seldom see accidentshappening in
well planned jobs.
Precisedetails
Planning isnot always easyand, especially
duringdemolition jobs, it canbe extremely
difficult to calculate the correctweight
of the load that youwill endupwithonce
it’s cut loose.
Careful planning isneededprior to each
and every jobandall knowledge from
prior accidentsornearmisses shouldalso
be included.
Planning is important, and failing to
plan isplanning for failure. Thewhole
process shouldbewhat is calleda
A telescopic boom that bent after it hadbeen
repaired. The customer acknowledged that the
previous repairmight havebeen insufficient and
yet refused for it tobe repairedby theOEM
Figure 1: Howa load is distributed strongly
depends on thepositionof the centreof
gravity in relation to the crawler tracks
>
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