Bruno Massicotte, professor of civil engineering at Polytechnique Montréal, is surprised that Tuesday’s collision caused the loss of the Francis Scott Key bridge in Baltimore. The Press spoke to him.
Q. How do you explain that the Francis Scott Key Bridge collapsed so quickly?
A. The problem was not at the bridge level. The bridge was designed to withstand hurricanes, traffic, and the load of the bridge. The bridge was in service for over 45 years, and all indications were that it was adequate.
But what is surprising is that the bridge was so vulnerable to a shock from maritime traffic. It appears that there were no protective elements to protect the bridge pillars, or that they were very small or ineffective.
Q. What kind of protection are you referring to?
A. It would often be too expensive to ensure that the pillars of a bridge could withstand an impact from maritime traffic. So the solution is to put protection that prevents collisions. For example, we can put islands which form large structures at water level around the pillars of the bridge. These islands will act like shock absorbers that we see on the road network near motorway exits. They are there to absorb energy during an impact. The energy has to go somewhere. Often the boat will break. It stops dead.
In this case, it seems to have been non-existent, even though we are talking about a bridge located in the United States, in an important shipping lane. For an engineer, whether a bridge is small or large makes no difference. We have to protect it, we have to think about all the scenarios.
Q. Do you believe that other similar bridges are vulnerable to this type of accident?
A. If I were the owner of a structure, I would ask my engineers this morning if we have bridges like that. The Quebec Bridge was also hit several years ago by a boat which had a rudder problem. But the damage was more significant for the boat than for the bridge (the St. Lawrence Seaway Management Corporation [CGVMSL] said Tuesday that the St. Lawrence bridges were “safe and efficient”).
Sometimes it could be a pleasure boat that hits a smaller bridge. It’s not impossible to have an impact. We have to ask ourselves the question. Engineers, normally, have thought about it. I think the Baltimore video is going to be seen all over the world and people are going to draw important conclusions from it.