Connected monitoring of a historical monument: auscultation of a church bell tower

Since the start of the school year, the church has been subject to a continuous structural monitoring following a diagnosis that highlighted a tipping phenomenon of the bell tower, taking part of the structure with it.

The objective of this connected instrumentation is clear: observe, understand and act.

It involves auscultating the movements, analysing the periodicity, and detecting any acceleration, in order to size the necessary repairs — or confirm their unnecessary — to sustainably preserve this historical heritage.

A complete movement monitoring system

For this mission, five connected FEELBAT sensors have been deployed:

• Four crack opening sensors DELTA L+, installed in the nave and attic to measure the movements of the through fractures ;
• An inclination sensor DELTA R+, positioned in the bell tower, measuring the angle variations according to two axes.
• One FEELBOX 4G to transmit data remotely

The measurement data is correlated to the ambient temperature, which allows distinguishing the natural thermal expansion movements (the building's “breathings”) from the actual structural evolutions.

Understand before acting 

Like the Leaning Tower of Pisa, whose decades of monitoring have allowed for interventions to be adapted without altering the structure, the DELTA R+ inclinometer system allows here to disassociate normal environmental variations from an abnormal structural drift.

Combined, the angle and crack opening measurements provide a robust and precise analysis of the building's behaviour, a true aid to technical decision-making for engineers and structural diagnostic experts.

Data transmission and real-time monitoring

The entire system relies on a continuous and secure transmission of data to the FEELBAT Cloud platform.

This centralisation allows for a real-time monitoring, a instantaneous visualisation of measurement curves, and automatic alerts in case of exceeding critical thresholds.

The energy autonomy of the sensors and their communication via Bluetooth, Sigfox or 4G ensure a reliable and continuous monitoring, even in isolated or hard-to-access sites.

The FEELBOX: the 4G gateway for monitoring continuity

For this project, a FEELBOX gateway has been installed to ensure the data transmission from all sensors, even through the thick walls of the bell tower and the attic.

Autonomous, compact and easy to deploy, the FEELBOX 4G allows for maintaining the connection between the sensors and the FEELBAT platform, when the Sigfox coverage is limited.

A decisive asset to ensure the reliability of monitoring and the continuity of the monitoring of the monument.

FEELBAT, the French reference for structural and geotechnical monitoring

FEELBAT designs and manufactures in France a complete range of connected sensors for structural and geotechnical monitoring : inclinometers, crack meters, extensometers, moisture sensors and piezometric level sensors.

Thanks to its web & mobile platform, FEELBAT allows design offices, local authorities and project managers to monitor in real time the evolution of their structures, to prevent risks and to preserve the built heritage.

🔗 Learn more : www.feelbat.fr

📍 Project partners : KIMSE Diagnostic – SID Expertise