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 a massive construction project on a new £1 billion station on Tottenham Court Road Station in London’s West End, 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. 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. The client accepted the VE proposal, which resulted in significant savings to the project and eliminated 26 days of scheduled construction.

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Reference:
Thurlow, P., & Lipscombe, R. (2014). The Use of Shape Accel Arrays (SAAs) for Measuring Retaining Wall Deflection. In J. Wolosick, A. Marinucci, S. Ballenger. Proceedings of the 39th Annual Conference on Deep Foundations. Atlanta, GA: DFI.

Outcomes

  • Eliminated 26 days of construction
  • Data proved planned wall prop could be omitted
  • Measured deflection in retaining walls
  • Produced data with better resolution