Infrastructure collapse fits two broad causes:
- Old infrastructure, in service for a long time, many times for several decades, whose maintenance has been neglected for a while.
- New infrastructure, in service for only a few years at most, which were designed and/or built incorrectly.
In my opinion, these are two very distinct failure mechanisms which cannot be compared one vs. the other.
In Mexico City we have just had a couple of weeks ago the failure of a span on the subway’s line 12, which is the newest by far.
Several other lines are close to 45 years older and yet have successfully withstood several large earthquakes without major damage. To me, the line 12 failure is a clear example of the latter cause.
I ignore the details of the building failures mentioned on the posts above, to determine to which group they belong.