This is a classic example of why AASHTO does not allow teenagers in motorcycles with subwoofers to have parties on public structures. Deplorable, just deplorable... Very poor enforcement by the party police here.
I don't like things moving, especially when those things are bridges, overpasses, buildings or other structures which I have designed.
The Red River floods every year. The entire area is flooded each and every spring. In the Winnipeg area, extreme caution is required to prevent this type of failure. It is not an easy problem to contend with. But it would be interesting to learn what type of foundation was used for this particular bridge.
Looks to be more of a slope failure issue to me. From the newspaper picture I think I see a crack up slope from the distressed pier. After this springs flooding, I'm sure alot of soil may have been moved. I live 220 miles up stream from there.
Most foundations in this area are supported on end bearing caissons or friction piles. Likely with the loads anticipated, the bridge is supported on end bearing caissons... but judging from the movement, I'm not sure.
The unofficial story is that there was a lack of maintenance in replacing stone riprap at the base of the failed pier. The soil scoured away and a bank failure ensued. The lateral force from the bank failure caused a shearing failure of the piers.
In California we have this tongue in cheek saying that CalTrans builds all there brides with "buried treasure".
Meaning that they put so much effort and expense into the design of the foundations that no one ever sees.
I used to think of that as something of a derogatory term, but whenever I see foundation failures like this I learn to appreciate the value of the buried treasure.
