Load testing on the Clémenceau Bridge in Brest

Brest Metropole, in France, plans on operating a second tramway line as well as a High Level of Service Bus line (also called Busway or Trambus) in 2026. Their route includes the Clémenceau Bridge, an infrastructure built 30 years ago. However, this one has not been designed to support the weight of tramway and High Level of Service lines in addition to the road traffic. 

The contracting authority entrusted Sixense to perform the investigations and checks needed on site to refine the sizing of the reinforcement work planned on the structure, in anticipation of the new tramway crossing and the bus line. To do so, our teams carried out load testing during the night of the 25th to the 26th of February 2021.  

In order to successfully complete the operation, the traffic was stopped to make room for several loaded trucks of a total weight of 120 tons. The bridge has been equipped with targets on the beams supporting the bridge, all aimed by a theodolite which was itself connected to computers with our Geoscope software, recording in real time the least oscillation of the loaded structure.  

Nicolas Sanchez, our team leader in charge of this operation explains:  

“An infrastructure is designed for a certain traffic. It is very likely that it will need to be reinforced. It is already more or less what is expected. We have installed a prism under each 17 beams. We target each beam with a laser equipment. The aim is to see, when loaded, the infrastructure’s deformation. We immediately receive the raw results, but we will still have to process all the information in order to provide results for the Brest Metropole Organisation”