Memphis bridge’s unusual design puts it at risk for future problems

I'm an engineer who was part of the team that worked from 2015 to 2017 on developing a system to monitor the seismic performance of the Hernando de Soto Bridge that carries Interstate 40 across the Mississippi River at Memphis. When I first learned from the media last week that the six-lane bridge was closed due to a crack, my initial thought was that it was likely a minor fatigue crack in its initial stages. I assumed it was like most of the cracks I have seen in many of the bridges/steel structures at inspections I conducted in the past.