I think most of the connections were bolted, though your point that concrete construction tends too be cheaper seems accurate to me.

I also think that the maintenance that was going on was more invasive than is being let on – that is from my vantage of riding under it for the last couple of months. I could regularly see daylight through the deck, and it looks like they were making concrete and rebar repairs.

This is not to say that the maintenance was necessarily at fault – the collapse was so symmetrical and catastrophic that many factors likely led up to the failure.

Tragic all around.

On my way home I parked at West River/Franklin and grabbed my camera and tried to get closer but at that point the area was under lockdown.

I may be wrong, but I think not using that construction technique has more to do with the labor costs of welding up all that steel rather than the integrity of the design.

Time will tell.

It is too early to draw conclusions. However, based on the way the Star Tribune depicts the sequence of failure and the fact that recent inspections indicated no significant metal fatigue, it all seems to point to an initial design flaw or erroneous engineering calculation of some sort. It would seem to take a fundemental failure to bring the whole bridge down.

In 1967 there were no computers to perform the mathematics. There was no computer-aided design or modeling.

Channel 4 made the statement that a transportation official commented that a bridge would not be built this way any more.

I wonder if this disaster was only a matter of time?