7/23/2019 Tower Crane Slew Brakes Salman
1/2
Tower crane slew brakes
Key Issues:
Preventing catastrophic failure of tower cranes essential slew
brake release
mechanism maintenance
Introduction:
HSE investigations into the collapse of two tower crane ibs has
identi!ed that
there were problems with ade"uate maintenance of the slew brake
release
mechanisms#
$he purpose of this safety alert is to advise owners and users
of steps to be taken
to ensure that tower crane slew brake release mechanisms are
maintained in ane%cient state& in e%cient working order and in
good repair# $he emerging
!ndings from the HSE investigations indicate that the
operational e%ciency was
compromised by lack of maintenance& in particular&
insu%cient lubrication of the
slew brake release mechanism# $his alert provides supplementary
information to
HSE Health and safety bulletin '() *+*,-. Preventing
catastrophic failure of
lu%ng ib tower cranes in high winds#
/ackground:
$ower crane ibs are designed to free slew when out of service to
avoid high
loadings being placed on the crane structure and foundations
with risk of failure
or collapse# In order that a tower crane can be placed in the
out of service
condition it is essential that the slew brake release mechanism
is maintained in
an e%cient state#
'ailure to maintain the release mechanism can result in the
operator being
unable to fully release the slew brake when placing the crane in
the out of service
condition or the operator thinking that the slew brake is fully
released when it is
still partially engaged# If the brake is not fully released the
upper slewing
structure will not be able to slew freely in response to
changing wind directions#
$his could result in the ib or whole crane collapsing in strong
winds#
0ction re"uired:
(wners and users of tower cranes should ensure that tower crane
slew brake
release mechanisms are inspected and maintained in line with
instructions issued
by the manufacturer# 1here crane manuals do not stipulate
release mechanism
maintenance instructions the manufacturers should be asked to
provide details#
Instruction should be provided to operators and maintenance
personnel as to howslew brake release mechanisms should be
checked& inspected and maintained#
