Interesting article about inspection findings:
http://www.startribune.com/10204/story/1350090.html
Comments?
Well, the reporter seems intent on hyping the crack reports as much as possible, but then, the bridge did fail, and maybe that’s not such a bad thing. Maybe it’s time to tighten up our bridge maintenence standards.
It bothers me that nobody seems to be looking at how the cracks seem to group, and why that might be so. Most of the cracks by far are tack welds on stiffeners, inside box beams and reinforcing webs. I always prefer bolts over welds, but even so, you have to look at whether these members are getting twisted, pulled or squeezed beyond design limits.
If so, why?
The frozen expansion joints and roller bearings might be a good place to start. They’re there for a reason.
Which brings up the second most numerous grouping of cracked members, direct damage resulting from frozen expansion joints and roller bearings.
Right there, you have all the reason you need to spend whatever it takes to keep those joints and bearings moving freely.