Bouygues Travaux Publics: Structural Monitoring

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the project

The future 33km-long Line 15 – South of the Grand Paris Express will comprise 16 stations and 38 ancillary structures.

The line will link the Noisy-Champs and Pont-de-Sèvres stations in just thirty-five minutes, thanks to an automatic network.

The Fort d’Issy – Vanves – Clamart (FIVC) station will be located partially beneath the existing Clamart station, providing an interconnection with Transilien Line N, thus ensuring that the Grand Paris Express connects with existing transport networks.

Nearly 50,000 passengers will use the station every day. The works are divided into 2 construction sites, covering an area of over 6,000 m².


Located in the municipality of Clamart, the FIVC station site is at the junction of three other towns in the Hauts-de-Seine department: Issy-les-Moulineaux, Vanves and Malakoff. Located in a highly urban context, controlling structural risks is a major challenge for the successful completion of the works.
What’s more, as this new service will be built close to the existing Transilien SNCF line N, the existing tracks must not be affected by the ongoing works.

For this project, the instrumentation will cover :

  • 500m of SNCF track,
  • SNCF buildings and premises,
  • Cast walls and secant piles,
  • Temporary bollards for the station box,
  • TBM arrival shaft.

Duration of project: August 2019 - October 2023

uby solution

To meet the instrumentation needs of the FIVC station site, we have set up a series of measurements to cover the monitoring of surrounding structures as well as retaining structures.

Measurements of surrounding structures

We use topographic prisms to measure deformations (in 3D), and façade clinometers to measure tilts on buildings within the site’s Zone of Geotechnical Influence.

Measurements taken on support structures

For the secant piles alongside the SNCF tracks: installation of inclinometers in boreholes (to measure vertical deformations), with automatic and manual readings depending on the construction phase.
For the wall of the SNCF technical premises: monitoring of tilting using automatic clinometers and installation of a set of topographic prisms inside the underground structure of the future station to monitor convergences.

We installed automatic theodolites to obtain continuous measurements of all the prisms on the surface (buildings, SNCF tracks, SNCF surroundings) and in the station box.

All measurements collected are available on our UBY platform. Our data visualization tool enables us to monitor the site environment in real time, and to keep a constant eye on any impacts. It also enables frequent, up-to-date reporting. An alert system is also available.

Benefits for the worksite

Data collected and real-time alerts in case of any abnormal movement of the tracks allowed for the normal operation of the suburban train line under which the construction operations were being executed. 

Our UBY Structure case studies