In defense of this and all bridges, no doubt what they are calling "structurally deficient" is based on a number that all state DOTs, per federal mandate, assign to all their bridges, called the "sufficiency rating". Sufficiency rating is based on several factors, and condition is only one of those. Others include:
- Geometrics (sight distance, shoulder width, approach and departure alignment, adequacy of guardrail)
- Load-carrying capacity relative to when new
- Load-carrying capacity relative to current design standards - this one always kills because design loads keep getting heavier
A low SR doesn't necessarily mean the bridge is weak, or about to collapse. In Albuquerque, we have a bridge about 2 years old whose SR is low enough to be considered "deficient" - but it's because the urban location forced it to have poor geometrics (that's the new Pennsylvania over I-40 for those playing at home).
Here's another trap: once a bridge's SR gets down to a certain level, it qualifies for federal rehab funds. However, once federal rehab money is spent on it, it's ineligible for more, for 10 years.
So, the point of all that is, don't take the news' claims of "deficient" at face value (of course, the fact that it collapsed seems to suggest that something was wrong).