TTCI recently developed fatigue screening tools for steel deck plate girder (DPG) bridge spans.1 A survey of rail industry bridge engineers revealed that for the steel DPG, the most common span type, about 70% of them are more than 80 years old, about 50% are more than 100 years old, and about 2% are more than 120 years old As steel bridge spans continue to age, fatigue becomes a factor for deciding whether to change inspection frequency or plan for eventual capital replacement of spans of certain lengths or designs. Fortunately, most of the older steel DPG spans were designed for steam locomotives with generous allowances for impact and lower allowable stresses than are used today.2 TTCI's fatigue screening tools like the fatigue screening charts can assist bridge engineers in identifying the spans for which maintenance or replacement efforts should be a priority.
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