Winner 2021

Award for
Minimal Structural Intervention

Project Description

A sophisticated piece of engineering analysis allowed the reuse of vast amounts of existing infrastructure. The new Elizabeth Line includes existing above ground sections installed with new overhead line equipment supported by gantries of up to 70 years old. Engineering analysis led to most of the existing structures being safely retained. This resulted in significant programme and cost savings.

Judge’s comments

Conventional analysis had determined that the majority of the existing structures could not be retained due to the new higher loadings, but the engineering team here took on the project and used structural engineering excellence to maximise the number of structures retained. Through the use of detailed non-linear structural analysis, they demonstrated that a vast amount of existing infrastructure was suitable to be incorporated into the new Elizabeth Line with minimal or even no intervention. The consequential cost and environmental savings were significant. The judges were impressed by the rigorous assessment procedure developed and how sophisticated structural analysis methods were utilised to justify many of the existing structures and to design simple strengthening measures on others.

Project overview

Structural Designer

  • Buro Happold

Client Name

  • Network Rail2


  • London, UK

Principal Contractor

  • Costain

Key Contractors

  • Keltbray – Sub-contractor to Costain 

Year Submitted

  • 2020