Instrumentation and monitoring of the construction site during the works
December 17th 2020
Project : Chartres and Gallardon’s grade seperation replacement
Client : Demathieu&Bard
Location: Massy
Type of monitoring: Railway instrumentation, temporary retaining walls and frames.
The project objectives:
Real-time displacement monitoring of all structures during the works for the replacement of the two grade separators.
Stakes:
Guaranteeing a precise monitoring to ensure the safety of the RER C, B and TGV users.

Our solutions:
Cementys is working in close collaboration with Demathieu&Bard, to carry out the instrumentation and monitoring of the construction site during the works.
We will be installing Robotic Total Stations, In-place inclinometers and TiltLOGs (tiltmeter) spanning on a 24 months period.
The goal of an automatic monitoring is to possess in real-time the following data:
- Railways alignments and levelling
- Catenary posts displacements
- Displacements of diaphragm walls, masonry supports of railway bridges and sound screens in x,y,z.
- Temporary retaining walls tilt
- Neighboring buildings tilt
The mechanisms will be installed on:
- The railways and catenary posts of the C, B and TGV lines.
- Lagging and retaining walls
- Sound screens, gantries and masonry supports.
Because the project includes multiple steps, our engineering team will have to work closely with Demathieu&Bard and make available their know-how and expertise, depending on the works progress.
All the different installations, removals and reinstallations are set. The first installations for the monitoring of the lines B and C railways began in November.
The data is added to our visualization platform THM Insight, and the different alarm thresholds are set.
