Charles de Gaulle Express Project

The Charles De Gaulle Express project is part of  Le Grand Paris Express which revolves around a public transportation network plan consisting of four metro lines around Paris, along with the expansion of two existing lines. The goal of this railroad project in the Ile-de-France region is to connect the Paris-Est train station to the Paris-Charles-de-Gaulle airport in less than 20 minutes. With a budget of more than 1.7 billion euros, the CDG Express is a major project that will shape Parisian mobility in the near future.


Once again, Cementys has been recognized for our reliability, responsiveness and technological solutions by providing a high-precision automatic topographical monitoring for one of the largest Parisian railway projects dating back to the beginning of the century while accompanying Eiffage and SNCF Réseau on one of the first works of the CDG express in Tremblay, Seine-Saint-Denis.


Cementys monitors, in real time, the impact of work on the RER line B. We do this through our 6 fully automated theodolites, 500 prisms located on the rails and our innovative data processing softwares.

Over the course of 3 months, Cementys will accompany SCNF Réseau on monitoring the impact of the sewage clean-up operation on the RER B North line.


New Monitoring project : Grand Paris Express Line 16 Work Package 2

We are pleased to collaborate with Salini ImpregiloNGE consortium on the construction of the new line 16 of Grand Paris Express Project.

The monitoring job of Line 16 Work Package 2 deals with the Tunnel portion between the connection structure at the Aulnay operation center and the Bel-Air in Chelles (Seine Saint Denis), that will be commissioned by 2024.

The construction of a 11.1 km tunnel and four railstations – Aulnay, Sevran-Beaudottes, Sevran-Livry, Clichy-Montfermeil will be monitored in real time through our latest technologies (DeltaLOG robotized total stations, Vibrating Wire Sensors, LoraLOG data loggers, Fiber Optic Sensors, InSAR and GNSS remote sensing, THMInsight real time database)

Monitoring tasks are numerous :

  • Existing Building subsidience monitoring in the geotechnical influence area during construction works
  • Existing Building subsidience in the geotechnical influence area during tunelling (TBM)
  • Railroad geometry monitoring in the geotechnical influence area during tunneling
  • Existing underground Network monitoring in the geotechnical influence area during tunneling
  • Geotechnical Monitoring with the our GEOTYS subsidiary (In place Inclinometers, Extensometers, Piezometers)
  • Data Visualization and Interpretation though our THM-Insight database with 24/7 alarm systems (data managers in France and Vietnam)

Combined with other Grand Paris Express & EOLE projects, Cementys will monitor 11 TBM (13 drives) and the construction of more than 40 railway stations or ventilation shafts around Paris in the next couple of years.


Offshore Riser Tension Monitoring

Late 2018, Cementys engineering team finalized its first deepwater riser real-time monitoring project.

The instrumentation operation took place in the Gulf of Mexico, on an existing Tendon Leg Platform (TLP), exposed to frequent Loop Current events.

Vortex Induced Vibrations (VIV) of a riser in severe loop currents can decrease the riser fatigue life and thus may have significant cost impacts.

VIV suppression devices are essential to minimize those events, eventhough VIV behavior presents one of the biggest simulation uncertainties facing the riser engineers.

This shows that full scale monitoring is essential to improve our understanding of VIV response of risers equipped with VIV suppression devices.

Cementys designed and set up a system to measure the strain variation of Top Tension Risers (TTRs), focusing on one of the regions where fatigue damage is expected to be greatest : the top of the riser, around 20 meters above sea level. The objective is to compare efficiency of the different currently installed VIV suppression devices and estimate the induced fatigue damage during a single Loop Current event.

The system is based on the ExtensoVib vibrating wire strain sensors, allowing for accurate strain measurements, with a resolution below 0.1 microstrain.

Each riser is equipped with six ExtensoVib extensometers with a 60° separation: 3 sensors for one monitoring system, 3 others for redundancy.

Sensors are connected to two dynamic data loggers, making a high frequency measurement (20Hz) for high frequency riser oscillations.


ExtensoVib risers are bonded directly on the riser metal surface, without the coating, to measure directly the surface strain, without drift or recalibration for a period of several years.

Cementys has a remote access to check the incoming data. The real-time axial loads and bending moments are analyzed in correlation with loop current conditions to follow the fatigue damage accumulation.

ExtensoVib sensors represent a cost-effective solution for riser monitoring projects.


Professional Training : Monitoring of Specific Defence Infrastructure

Since November 2018, Cementys organised new military training sessions every month, at Palaiseau’s Campus for the French Army Corps of Engineers (SID departement of French Army).

Hundreds of Military Engineers will attend this 2 day training program to inspect and monitor specific military assets (harbours, dams, reservoirs, railways, bridges, nuclear facilities, airport runways).

Based on numerous case studies, Cementys Experts explain how to identify, characterise and prevent/repair ageing phenomena or degradations for those specific military facilities.

Picture of the first Promotion :

These Trainings deal with infrastructures :


  • High-rise Building, Semaphore And Historic Monument
  • Water Tower
  • Transmission mast, antenna, Radar dome
  • Cliff and Quarry
  • Retaining Wall


  • Building
  • Structural art
  • Underground works 
  • Marine structures
  • Aeronautical pavements

GEOTYS _ Geotechnical Monitoring

GEOTYS offers a wide variety of automatic monitored geotechnical instrumentations :

Piezometers (groundwater level and pore-water pressure)

Inclinometers (vertical and horizontal)

Extensometers (in-place or manual measurements)

Crack monitoring and Tilt Meters for surface buildings

Settlement gauges

Ground Vibration Monitoring

Direct and Inverted Pendulums

Typical Applications :

Ground Movement Monitoring

Landslip Monitoring

Foundation Monitoring

Tunnel Monitoring

Dam Monitoring

Pile Testing

Soil Investigation

Our up to date equipment :

GEO205 COMACCHIO drilling rig (2,7t – 44 HP – 480 daNm)

GEO305 COMACCHIO drilling rig (5,1t – 75 HP – 1100 daNm)

Injection Pumps

Cement-Bentonite Mixers


Drilling parameter loggers (Lutz)

Ground Penetrating Radars (GSSI, USRadar)

MicroGravimeter (Scintrex)

BoreHole Cameras




Thanks to the new wireless telecommunication technologies, data access and visualization through Internet allow us to follow in real time the evolution of instrumented structures. This monitoring is essential during critical phases such as installation, production, maintenance or even when civil engineering works happens nearby.

For several years, Cementys uses and improves its supervisor software, called THMinsight, to display these indicators. These are necessary to control, monitor and alert about all the events which could damage an infrastructure. See below two new functionalities.


Geographical Information System

Our database server, set in Palaiseau (France), now integrates a GIS database, which is adapted to fit with a high demand of sensors, in urban projects. For example, thanks to this method, settled zones can be calculated and easily visualized.


Monitoring of railway infrastructures

This new functionality is adapted to the monitoring of railway structure geometry. In real time, it provides information about: levelling, pitching, the “gauche” and the slope of railways. These indicators are useful regarding the monitoring of the deformation of structures and ensure security of trains and their users.


CNEA has relied on Cementys’ fiber optic measurement technical expertise and know-how

Anticipating future energy challenges, Argentina asserts its will to increase its atomic energy industry. Argentina’s government has entrusted CNEA (Comisión Nacional de Energía Atómica) with the development of a new type of nuclear reactor, from low to medium electrical capacity, completely engineered and designed in Argentina.

The project, called CAREM 25, began in early 2014 at the Atucha nuclear site in the province of Buenos Aires.


CAREM 25 project

This new generation reactor, of reduced dimensions, will produce 25 MW which corresponds to the power supply of a 100 000 inhabitants city.

Cementys provides technical expertise to CNEA for the design and the implementation of a structural instrumentation and monitoring meeting the project’s requirements.

For this CAREM 25, Cementys favored to set-up a “long-term” instrumentation based on robust and viable Vibrating Wire sensors. These technology based sensors have been installed on French and worldwide nuclear power plants for more than 40 years and their reliability is no longer to be demonstrated.


MicroVib® Sensors

In addition to so-called “traditional” sensors in the nuclear industry, CNEA has relied on Cementys’ fiber optic measurement technical expertise and know-how, to integrate optical fiber cable into several parts of the reactor’s slab and concrete walls.

“For such an ambitious project that is the CAREM 25, we desired to ensure a traditional structural monitoring (Vibrating Wire sensors), and improve it with an advanced technology that is optical fiber distributed measurement in order to better understand the behavior of the structure”, commented Vincent LAMOUR, technical director and civil engineering expert at Cementys.

Distributed measurement with optical fiber gives added-value data since temperature and strain perceived by the fiber optic cable is collected each meter over its entire length.

Slab’s instrumentation was installed during summer 2016, and allowed to verify the good behavior of the concrete during its pouring in October 2016. Optical fiber measurements emphasize the same temperatures and strains as recorded by the Vibrating Wire sensors, and moreover, provide many additional measuring data.

A dedicated web interface allows the CNEA Civil Engineering and Instrumentation engineers to visualize real time data from the various installed sensors.

Cementys’ engineering teams will continue to contribute to the coming phases of the project with their expertise, until the site’s commissioning in the first half of 2019.



Cementys instrumentation map


CAREM 25 nuclear reactor












Pipeline leak detection

Optical fiber: a revolution for pipeline leak detection

Pipeline leak detection is so important… Even though pipelines are still the safest way to transport oil and gas products, spills and leaks may occur. These incidents can have an important environmental impact, incur cleaning costs, and deteriorate the company’s image.

Several technologies have been developed to monitor the pipelines to detect or prevent leaks (ultrasounds, flow monitoring, smart pigs…). Optical fiber recently brought a revolution to the sector: we can now have a distributed measurement all along the line using telecommunication fibers, giving us every foot the temperature, strain and vibrations of the pipe.

Most optical leak detection systems today use Distributed Temperature Sensor (DTS) monitoring. When the product is at a different temperature than the exterior environment, a passive monitoring system will be able to rapidly detect leaks by looking for hot or cold spots along the line. This type of measurement has an extremely low false alarm level, especially if there is a big difference of temperature (LNG, heated oil, pressured gas with Joule Thomson effect…).

But when the product is at the same temperature than the exterior environment, a passive DTS monitoring will not work. This is why Cementys developed an Active DTS monitoring system: in this case, we use a metallic cable to heat the line, in order to analyze both the temperature and the temperature variation. This real time analysis gives out the thermal capacity of the environment, directly linked to the presence of oil.

For long lines, Cementys developed the Transient Monitoring System. To use an active DTS system, one will need power to heat the line (around 1W per meter). We can see that this solution is hard to implement for lines longer than a mile. Our Transient Monitoring System analyzes the temperature variations due to daily and seasonal changes. After a learning period, the system is capable to detect a change in behavior therefore a leak.

Thanks to those technologies, Cementys can help you to monitor all of your lines.


Voids detection in Marine docks by Ground Penetrating Radar (GPR)

The GPR method uses radar propagation and reflection of electromagnetic waves of different frequencies.

A microwave antenna transmits pulses of very short duration in the soil or the structure, generally at frequencies ranging from 16MHz to 2.6 GHz (according to depth and resolution objectives). When the waves encounter a contact between two different dielectric permittivities environments, part of their energy is reflected, while the other goes deeper.

The acquisition system measures the travel time of the radar wave between its transmission and its reception. The depth is calculated using the travel time and the relative dielectric permittivity εr of the soil (v = c /√εr where c: speed of light and v: soil velocity).

However, this depth may be lower or even 0 if there is the presence of natural or artificial screens (clay soils, rebar mesh, metal plate, etc.).

During this GPR campaign, we used a 270MHz antenna that allows auscultation close to 6m deep.

Picture missing 

The above radargram highlights anomalies, between 32 and 48 abscises, linked to voids extended between 3.5m and beyond 5.6m deep. GPR measures detect also geometric targets regularly spaced that appear to be related to wooden beams. 


Distributed strain monitoring of tunnels

Distributed strain monitoring of tunnels

Distributed strain monitoring of structures using optical fiber sensing is a brand new technique which has opened new possibilities in tunnel survey. Cementys was mandated to install its SensoluxTM® sensor for two different structures: the brand new extension of the Parisian metro line 12 and the 35 years old Fréjus tunnel, the longest road tunnel in Europe, between France and Italy. The cable-sensor was set up on sensitive areas during important operations: a fire-access during tunnelling for RATP and underneath a fresh air gallery before the excavation for the SFTRF. The optical sensor is based on Raman (respectively Brillouin) backscattering to measure temperature (respectively deformation).


The cable-sensor detects the deformation over its whole length, without any blind spot, with a spatial resolution of 0.5m, a precision of ±5µdef and a range of several dozens of kilometres.

The small diameter of the sensor (2mm) makes it easy to integrate in tunnels by gluing the optical cable in grooves carved on the concrete. The optical cable is thus protected for long-term monitoring, without any maintenance of the measure system and with no deviation of the sensor. Moreover, the installation presents a low level of intrusiveness due to the fact that the cable is integrated into the concrete.

Any circumferential deformation of the structure is transmitted to the cable rings, cohesive to the concrete, and detected by the interrogators.

The first measure is considered as the baseline and the following measures are compared with the first one to track relative motions. Consequently, the initial stress of the cable due to gluing does not impact the measures.

The sensor measures the deformation (compression or expansion) of the concrete to detect local damages as cracks or global motion such as convergence phenomenon. Data is retrieved from a long distance with the optical fiber for real-time monitoring of the tunnel thanks to optical technologies.