Instrumentation of Grenoble’s Perret Tower

Instrumentation of Grenoble's Perret Tower

Objective of the instrumentation: Measurement of the evolution of the Tower’s tilt and its direction.

A true landmark in Grenoble, the Perret Tower, is an observation tower and the first concrete tower in Europe, and is currently undergoing rehabilitation work. After being closed to the public for over 60 years, it will reopen in 2023.


Aging of the tower occurs due to the corrosion of the metal frame, and the concrete cracks and ruptures weaken the structure. Construction has started on a section of the building.

The instrumentation carried out by Cementys includes the installation of the following sensors:

  • 3 INCLINOMETERS BI-AXE on three levels of the tower


These wireless inclinometers communicate with the Cementys servers via a modem installed on the ground floor of the Tower. Since the tower is under restoration, the installation of wireless inclinometers will minimize the impact on future work.

Cementys auscultation tour perret
Cementys instrumentation tour perret grenoble


The measurement consists of a series of sensors hydraulically connected to a reference tank positioned in a stable area. Each sensor contains a high-resolution pressure sensor that measures the difference in liquid level between the sensor and the reference tank. Thus, the location of the tower outside the structure was chosen as a solution for installation of the support position. For this purpose the reference was installed on a stable concrete block outside and the hydraulic line connected to the water sensors via an aerial path.

The sensors will work for 3 years and will monitor the behavior of this historical monument as well as the safety of its operators.

France 3 Rhône-Alpes report highlighting the work carried out by Cementys engineers

Misa Rakotomavo, Monitoring Manager at Cementys for this project, explained the stakes of this surveillance for the cameras of France 3.

Discover the replay (french) presented by France 3 Rhône Alpes dedicated to the tests on the concrete of the Perret Tower in Grenoble.