“…Over time, they are exposed to many degradation processes due to 3 environmental factors and changing loading conditions. It is found in recent studies 4 that more than half of the Europe's 1 million bridges were built before 1965 and so 5 they are nearing the end of their 50-year design lives [1]. Their replacement cost is 6 equal to 30% of gross domestic product so it is not feasible to replace them.…”