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Increasing design load for bridges saves thousands of hours

Approximately 2,000 hours of staff time will be saved during the lifetime of a single corrugated metal pipe or precast concrete structure simply by increasing the design load of the structures. “Potentially, we could be talking about hundreds of structures,” explained Bridge Asset Engineer Dan Gorley.

ITD is responsible for analyzing bridges for overweight truck permits, but that can prove to be a time-consuming task if a heavier load has to cross a variety of bridges. So the ITD Bridge Asset group has increased the loads designed into the new bridges, so essentially they are solving the problem on the front end, rather than having to spend time worrying about overweight permit analysis during the life of the bridge structure.

“This allows us to eliminate some restrictions on commerce associated with permitted loads traversing these bridges,” explained Gorley.

Gorley said they have been working with the industry on the problem for quite some time, and just recently began using the new guidelines on some buried structures.

The hours saved are estimated at approximately 40 hours per year for a 50-year design life. Bridge Asset Management staff hours were estimated at 30 hours of time saved for in-house load rating, and analysis time for overweight permitting of the structure.