Crossrail: Construction of The New Western Ticket Hall

ShapeArray measured retaining wall deflection, reduced construction time and costs

Measurement data allowed engineers to execute a value engineering proposal

As part of the massive Crossrail project, construction on a new £1 billion station on Tottenham Court Road Station began in London’s West End. Construction on the news station’s Western Ticket Hall started in 2012. Engineers planned five levels of temporary props to bolster and stabilize the temporary retaining walls.

Nine ShapeArrays were installed vertically into the retaining walls to measure deflection. These ShapeArrays were installed alongside inclinometer casings to compare the resulting data. Engineers set a number of different alarms to notify staff when movement exceeded their thresholds. The data produced by the ShapeArrays allowed engineers to draft a Value Engineering (VE) proposal to omit a planned propping level. The data showed that forces acting on the retaining walls were within allowable tolerances without the additional prop. Crossrail accepted the VE proposal, saving the project £715,000 and 26 days of construction.

 

Outcomes

  • Saved project £715,000 and 26 days of construction
  • Data proved planned wall prop could be omitted
  • Measured deflection in retaining walls
  • Produced data with better resolution