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Cranes' Chains Change on Thames
01 Sep 2004
West Midlands UK crane manufacturer J Barnsley Cranes (JBC) has won a rollover contract to service, refurbish or replace all the cranes, hoists and jibs it supplied for the Thames Barrier when London's flood defence system was first constructed over 30 years ago.
The original order, placed by Davy Cleveland Barrier Consortium, the contractor for the steel gates and operating machinery, was for the supply of more than 40 cranes and jibs for the seven offshore piers which control the barrier. After commissioning, responsibility for operating the barrier passed to the UK Environment Agency, which asked JBC to carry out an appraisal of the equipment it had originally supplied.
Each of the seven offshore piers is equipped with five cranes, ranging in size from 5 to 12 tonne capacity. One is above the waterline on top of each pier and two are in each of the upper and lower machine rooms which are situated below the waterline in the base of the piers. The cranes are installed over the hydraulic mechanisms and are used to help with maintenance of the hydraulic cylinders, power packs and motors which raise and lower the barrier.
An inspection by JBC staff revealed that over the 30 year period, many of the crane parts had become obsolete. For example, the chains were based on Imperial measurements whereas today all work is in metric. As a result, the sizes of chain originally used on the barrier are no longer available and JBC was asked to replace them with the modern metric equivalent. This involved changing all the hoists whilst retaining the existing trolleys.
MJ Information No: 19818
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