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January 2013
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ELEVATOR WORLD
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The system has a traction sheave and return pulley/di-
verter sheave, which is tensioned in a similar fashion to an
escalator step chain. Once the cable had been tensioned to
the correct height, the next step was to carry out the rigor-
ous testing and commissioning process for the whole sys-
tem. Another engineering challenge faced was that of the
flight path into the nearby London City Airport. The lower
end of the emergency approach into the airport is 110 m,
only 23 m above the top of the south tower.
Designers also had to be aware of the possibility of a
vessel striking a tower. Though the risk was assessed as
low, a ship-impact system was employed to divert any
risk away from the towers. The south tower has been
constructed in the main river itself, which, again, pre-
sented challenges along with the limited construction
timeline. The project began in July 2011 and was handed
over on June 28, 2012. Completing the project in a little
over 10 months is quite an achievement, given the design
and construction challenges.
After the design stage, construction issues were also
abundant. The U.K. had its worst recorded period of in-
clement weather during construction, when the region saw
heavy rain on most days, as well as a period of snow.
The bed of the Thames River was found to be unstable,
which was no surprise given an earlier discovery of this
kind in the 1800s after similar weather. However, it wasn’t
anticipated that the problem would be some 30 m deeper
than expected.
Another challenging issue was designing the system in
such a way that all passengers could be retrieved in a timely
manner in the event of equipment failure. The design is
such that there is redundancy and system support including
an innovative emergency bearing system, incorporated in
case of a bearing failure on the main traction and tension-
ing sheaves. The bearing design was developed specifically
for this project, which marks its first use; however, the suc-
cess of the design means it will likely be adopted for future
projects around the world.
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A demonstration of the cabins’ accessibility
