Engineering
Designing Resilient Bridge Decks Against Fatigue Cracking
Quick fact
In steel bridge decks, fatigue cracks often initiate at weld toes or other stress concentrations, and the stress range (the difference between minimum and maximum stress) is far more influential on fatigue life than the peak stress itself—meaning a truck that causes small but repeated stress swings can be more damaging than a rare overload.
Why this is interesting
You might think a bridge fails from a single heavy truck, but most bridge decks are actually worn out by millions of ordinary ones. Why do structures that easily hold a truck's weight still crack over time?