Structural monitoring of the Normandy Bridge

The Normandy Bridge, a major structure that stands up to the elements

Since 1995, the Normandy Bridge is crossing the Seine estuary and connects Le Havre and Honfleur by a 2,141-meter long prestressed concrete and steel structure. It has a cable-stayed span of 856 meters. The deck of the structure accommodates 4 vehicular traffic lanes as well as bicycle and pedestrian paths. Its 184 stays, with up to 53 strands for the largest cables, ensure that the central steel deck is maintained for no less than 654 m above the navigation channel.

The durability of this structure, a symbol of French know-how in terms of Civil Engineering but subject to the winds and tides at the Seine estuary, is ensured by regular and rigorous maintenance. This maintenace is backed by the monitoring of the structure with a set of specific sensors but also by the periodic control of the structure’s and particularily the ageing of the stay cables

 

Increased surveillance of the structure to ensure its durability

Between 2011 and 2018, Sixense installed and maintained a monitoring system composed of about a hundred sensors: displacement, inclination, force in the stay cables, temperature, vibration of the structure, weather station and even breakage of stay cable wires. This system, which measures both the external stresses and the structural responses of the structure, enables a better understanding of the structure and anticipation of maintenance operations.

Since 2011, Sixense has also carried out periodic testing of the stay cables to determine their level of aging and check their residual structural strength. The Uscan process, patented jointly with the Gustave Eiffel University, works on the principle of ultrasonic guided waves to check the health of the strand wires in the areas where the stay wires are anchored.

 

Thanks to these continuous and periodic measurements on the sensitive componentss of the structure, the CCISE* can anticipate and schedule maintenance operations that will keep this masterpiece of French Civil Engineering intact for many years to come.

 

CCISE*: Seine-Estuaire Chamber of Commerce and Industry