>In short the system of inspections is working. Actually no, it isn't working because it cannot possibly work, at least not with decades old structures (that h

>In short the system of inspections is working. Actually no, it isn't working because it cannot possibly work, at least not with decades old structures (that however do not collapse because they were often over-engineered, because after all they weren't built so shoddily and for a thousand other possible reasons). A bridge inspection more often than not amounts to a visual inspection, to detect cracks, check bearings, but while some elements of the structure are visible (as said bearings and concrete surface) the state of internal cables is hard or impossible to check, though there are some new techniques that look promising (though they are not yet AFAIK properly documented/standardized), as an example, JFYI: https://www.youtube.com/watch?v=pKWxpHsLBRk https://www.youtube.com/watch?v=pKWxpHsLBRk And there is another key point, norms have obviously changed a lot in the several decades since the construction, original calculations and drawings may have been lost, and there is the need to re-do the calculations with the new standards of loads and check whether the current loads/frequency of traffic is compatible with those the original project took into account.