2 July 2018
There is something special about megaprojects that brings out the best in engineering design and construction. It could be that the longer-term durations for the planning, design and build phases allow more measured and thoughtful decision making; it could be that the weight of public exposure and expectation creates an added incentive to succeed; it could be that the prestige of being part of the programme attracts the best teams in the best organisations; it could be that the extended schedule nurtures a team spirit and a collaborative way of working that is difficult to achieve in a typical shorter-term project.
The Elizabeth line will use above-ground sections of existing Great Eastern and Great Western tracks between Stratford and Maidenhead where new overhead line equipment (OLE) and traction power supply will be installed. The OLE is supported by gantries of various types and configurations. In the case of the Great Eastern, the gantries date from the electrification of UK railways in the 1940s. Initial structural assessment carried out had shown that existing gantries on the route were inadequate to carry increased loading from the upgraded OLE. However, a rigorous procedure incorporating detailed non-linear structural analysis was developed that eliminated some of the inherent conservatism in traditional codified approaches. Particular benefit was found in the case of the many types of slender structure where buckling was a governing factor. Using non-linear techniques, it was possible to demonstrate that families of structures were suitable for incorporation in the Crossrail (Elizabeth line) scheme. This paper describes the approach that was used. The project is remarkable for significant programme and cost savings that were accomplished using sophisticated engineering analysis. It is also noteworthy from a sustainability point of view, as it allowed the existing infrastructure to be reused.
Simon Pitchers enjoys this account of the creation of the London Olympic Stadium, both for its lessons on running successful projects and the fascinating facts that will enrich a dinner-party conversation.