Quality Wins Project of the Year

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. c

A demonstration of the cabins’ accessibility

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