Articles

Thoughts of the Minnesota Bridge Incident

By Anthony M. Davis 

It’s far too early to determine the cause of this tragic incident. At the time of this writing there are still the missing and the dead to be found or recovered. After the search and recovery phase, the investigation will proceed for many months ahead. Inspection and initial construction records (if they exist) will be pored over to identify potential roads to travel in the search for causal factors. Of those questions will be:  

• What was the expected life of the bridge given this specific design?

 

• Was it built to specifications?

 

• Where did the steel come from? What was the purity of the steel, the tensile strength and hardness of the materials?

 

• Was it the appropriate material for this construction?

 

• Who were the welders? Did they use mild steel welding rods or low hydrogen?

 

• Was the welding rods’ tensile strength appropriate for the project?

 

• Where did the rods come from? What was their quality?

 

• Were the welders certified? If so, by what standards? Were the welds inspected on site?

 

• What was the weather during construction and was the base metal properly prepared for welding?

 

• What are the preventative maintenance and inspection requirements on the bridge, starting from the time it was built until today?

 

• Were there any preventive maintenance or inspection periods missed? If so, why? Were they eventually conducted?

 

• What are the qualifications of those that inspect this bridge? There are eleven separate types of corrosion. Can the inspectors identify each of these and do they know the appropriate corrosion control measures needed?

 

• When structural issues were identified, what plans were in place to repair the bridge?

These are just a few of the many hundreds to be asked in the days ahead. As the weight and motion of vehicles pass over the bridge, the structure develops a certain harmonic effect of bending and twisting. In fact, looking at the metallurgic properties of the steel structure, there is a constant particle compression and expansion. The harmonic resonance of the steel spreads outward to main supporting structures, just as a pebble in the water transfers its force away from the center. The constant flexing of the steel then increases the potential for structural failure. In a (sort of obscure) representation, if a coat hanger were constantly exposed to a repeated flexing motion, it would eventually break. Fortunately bridges are built with better materials, but you get the idea.  

Ok, why I am going down this path? Because as we now know, there are many bridges within our nation that are structurally at risk. These same questions can easily translate over to those as well. Ironically, right after 9/11 there was a big push to identify and secure our critical infrastructure. I remember that well because I was engaged in many of those projects. Yet today, not much has changed.  

One area that surprisingly has not been discussed much in the past few days is the impact of this event and how it in effect, shut down the maritime transportation route. The area of the Mississippi River between mile markers 848 to 857 are closed. Cargo is not being moved and there is a direct affect of the nation’s commerce. Bridges are a vital part of our maritime transportation system. If they fail, waterways are closed and cargo movement stops. This is one of many areas I am covering in my upcoming book, “Terrorism and the Maritime Transportation System”. I’m not saying this was a case of terrorism, but our infrastructure certainly is a potential target.  

I’m not ignoring the human impact of this tragic incident. Family and loved ones are lost and I don’t want to think of those last frightening moments for some. But we have to look at this incident and identify and prioritize vital infrastructure in need of repair so this doesn’t happen again. I am completely in awe of those brave men and women who as first responders saw a need and ran to the call. It appears that law enforcement, fire and first responders are working well together and they are working smart. Afterwards there needs to be a detailed internal look at what worked and what didn’t - not to criticize, but to build, train and prepare our folks for the next one. 

Even so, this type of incident now needs to be a greater part of critical incident training. What alternative avenues of approach are available in each city should another incident like this happen? Are proper staging areas preset into an incident plan? Will those responding have a communications system that allows effective coordination and delegation from the Incident Commander? Is the Incident Command Structure a part of training? If so, are regular drills conducted? If so, do you kill off the leadership (during the drill) to identify knowledge and leadership issues? 

Now that this incident has been televised across the worldwide airwaves, our adversaries now know we have additional weak spots. This incident is truly a tragedy in lost and injured lives. It is also an opportunity for us to prepare and repair.