Bridges constructed in the 1950s and 1960s are at an age where rehabilitation is necessary to extend the useful service life. When additional dead load is added by the project or deterioration is observed, MnDOT requires pier caps be rated using the current design code; it should be noted that the live load used in previous design codes is different than current design codes. Analysis often results in low load ratings, but much of the expected distress that would result from such low ratings is not being observed.
This project would identify a bridge that could be used for measuring live load reactions under known loads. The bearings at a pier would be removed (temporarily) and replaced with load cells. The load cells would capture reactions as a known weight vehicle (possibly MnDOT plow trucks loaded with sand and weighed) as it moves slowly across the bridge deck. The measured results would be compared against the design analysis to better understand the load distribution from the superstructure to the bearings.