The heavy trucks that do not meet the weight limits cause very significant damage to the bridges of quebec’s road network. The lack of oversight is decried by the experts.
The Newspaper revealed Saturday that some 400 bridges in Quebec must be replaced due to their unsafe condition. One of the causes of degradation is the presence of heavy trucks on those structures, even when this is forbidden. In October 2018, when the inspection of a bridge in Mascouche, located on the Chemin Saint-Pierre over the creek from the Cabin round, the engineers of the ministry of Transport (MTQ), have registered that the “traffic is very busy heavy vehicle, even if the bridge is displayed in the restriction of expenses.”
The MTQ notes that there was a quarry in the vicinity of this bridge.
“It is necessary to discipline the trucking industry. It is very damaging,” said Mario Fafard, professor of civil engineering specializing in structures at the University of Laval.
In order to enhance the service life of a bridge, the MTQ may limit the tonnage.
“You can’t put a police on every bridge. This is not obvious”, adds the expert.
Heavy weight cause
These are not the cars that put the most pressure on the structures, even if they are more numerous, ” said Mr. Fafard.
“The worst are the heavy trucks, he said. Mainly the vehicles that drive badly the weight. Truck drivers must be aware of the signaling. Is it that there are offenders? Yes, they are everywhere.”
He also pointed out that some of the bridges do not meet the reality of today.
“The bridge of Arvida [Saguenay], it is solid enough to support trucks of the era in which it was built. The expenses of 1950 were much smaller than our costs today,” illustrates the expert structures. The president of the Fraternité des constables of the traffic control Quebec, Éric Labonté, critical of the lack of surveillance near the bridges that are at risk.
“What I deplore is that there are bridges with weight limited to 5 or 10 tonnes, and there is little to no monitoring, does it. When infrastructure is made of 5 tonnes, it must be said, the bridge is finished.”
Five times too big
Mr. Labonté reports that in 2016, he has intercepted a truck on the pont des Grandes-Fourches, in Sherbrooke, who came to pass over a bridge in tonnage limited to 10 tonnes. This last weighed in at 55.
“He was lucky not to be picking up in the Saint-François river,” he said.
Always the specter of the viaduct of the Concorde
The collapse of the de la Concorde overpass, in Laval, still has a major impact on the way in which one reconstructs and inspects the bridges today.
The tragedy that occurred on September 30, 2006 claimed the lives of five people.
“On the bridge of the Concorde, it was a way to design the bridges in the 1970s that we are not doing today,” says the engineer, Mario Fafard.
Nowadays, when designing a structure, said Mr. Fafard, we want it to be deformed without breaking, such as with metal or aluminum. This phenomenon is called the ductility.
“What happened to the Concorde, it was sudden. There was no evidence that warned that the bridge was not going well. It is often the case with concrete bridges”, he explains.
After the events, all of the bridges that were similar have been strengthened, ” said Mr. Fafard.
“We know that the way in which they have been made at the time was perhaps not correct,” he said.
Most of the 400 bridges to rebuild in Quebec are made with concrete, believes the expert.
“There is a certain improvement to the MTQ. Since that we are giving contracts to the private sector, it brings reinforcements for the inspections,” said Mr. Farfard.
The billions of corruption
“The collapse revealed the consequences of the lack of maintenance of the different road infrastructure,” says Marc-André Martin, president of the Association of professional engineers of the government.
In the reaction, and the result of the report of the commission Johnson in 2007 that followed the tragedy, the government has injected several billions of dollars to repair or rebuild the works, whose maintenance had been neglected, ” explains Marc-André Martin.
“These billions have led to corruption, because the MTQ has relied on the firms of geniuses-tips, he says. It threw open the door to schemes of malfeasance and collusion in the construction industry”, said Mr. Martin.
WHAT IS The STATE OF the BRIDGE OF YOUR REGION?
Our interactive map shows more than 2000 structures throughout the province. Learn more about their condition and check out the inspection reports.
WHAT do THE INDICES OF The STATE OF the BRIDGES
Combined index (ICS)
The combined index, included between 0 and 100, gives a good idea of the general condition of the bridge. It is composed of three indices, or the seismic vulnerability, the state of the structure and its ability to play its role. The lower the index, the more the bridge is vulnerable.
Index of material of the structure (IMS)
It allows to follow the evolution of the state of the materials of the bridge. Defects such as the disintegration of the concrete, steel corrosion or wood decay, shall be taken into consideration. The results are expressed on a scale of 0 to 100. The number 100 corresponds to the best condition.