In France, 3,000 municipal bridges have “major structural flaws”

An audit by the Center for Studies and Expertise on Risks, Environment, Mobility and Development (Cerema) analyzed the state of nearly 60,000 structures across the country. Around 400 bridges were urgently closed.

In Ménesqueville, in Eure, the mayor examines the condition of a bridge almost two centuries old. “There has been a lack of maintenance for decades, the last major work was done around sixty years ago,” laments Dominique Cahagne.

This aging heritage is the subject of particular attention, particularly since the collapse of the Italian bridge in Genoa in 2018, which caused more than forty deaths. The Center for Studies and Expertise on Risks, Environment, Mobility and Development (Cerema) shares with BFMTV the conclusions of a private audit carried out on the state of municipal road bridges in France.

Only a quarter of these nearly 60,000 structures, which include bridges and retaining walls, are judged to be in good condition.

400 bridges closed

Around 10,000 (25%) municipal bridges need short-term work, either repair or complete replacement, of which more than 3,000 (nearly 8% of the bridges analyzed) require emergency measures because they present “structural faults major”.

This study led to the immediate closure of 400 bridges across the country while 1,500 saw their tonnage lowered, that is to say that vehicles above a certain weight are now prohibited from driving there.

This state of deterioration which concerns nearly 10,000 municipal bridges in France “is linked to lack of maintenance and aging”, explains David Zambon, director of transport infrastructure and materials at Cerema.

“The first type of damage occurs when water infiltrates inside with growing vegetation: this makes it fragile over time and requires waterproofing and repair work,” he explains.

“There are then other types of damage such as concrete which ages poorly or iron systems which will rust,” adds the specialist.

The structures most affected are those which are subject to road traffic or which may be damaged by a river flowing underneath.

750 million euros

According to David Zambon, the cost of repairing the 3,000 bridges requiring emergency work is estimated at 750 million euros, a “high amount, which must be compared to the number of works”.

There is, in fact, a question about small municipalities, which do not necessarily have a qualified agent to maintain this heritage. In Eure, three bridges require major work at a cost of 640,000 euros. “We made requests for subsidies from state and departmental services,” explains François Baldari, vice-president of the Lyons Andelle community of communes.

David Zambon also indicates that a first wave of repair work programming has been launched for an amount of 50 million euros.

Extreme weather events

Due to the unprecedented bad weather which affected the Var department at the end of October, a bridge in Le Muy collapsed. “Torrential rains and exceptional phenomena can demolish a structure even if it has been properly maintained,” observes David Zambon.

The intensification and multiplication of extreme events linked to climate change accelerate the wear and tear of bridges. “The bridges which span the rivers are weakened by floods and droughts,” indicates David Zambon to Libération.

“There are also movements of the ground, shrinkage-swelling of clays in places. All these phenomena are accelerating and are not helping matters,” he adds, specifying that future work will take into account the issues related to changes in climatic conditions.

This Tuesday, November 26, the trial opens in Toulouse into the collapse of the Mirepoix-sur-Tarn bridge in November 2019, which left two people dead after a truck passed over this bridge built in 1935.