The Federal Highway Administration is advising state transportation departments that oversee fracture-critical bridges constructed of T1 steel to inspect butt welds, just in case they have cracks similar to those recently discovered on the Interstate 64 Sherman Minton Bridge between Kentucky and Indiana. On Sept. 9, the Indiana Dept. of Transportation closed the 49-year-old bridge—a double-deck structure spanning the Ohio River with two 800-ft main spans—after an inspection revealed a 2.5-in. crack in the butt weld of a tension tie—a lateral component crucial to reinforcing tied-arch structures.
T-1 steel is a high-strength material that was commonly used to construct bridges in the 1950s and 1960s. The September advisory specifies tension components constructed of T-1 steel prior to adoption of the so-called fracture control plan of welding codes recommended by the American Association of State Highway and Transportation Officials. Bridges constructed prior to adoption of the 1995 code may develop cracks due to a lack of hydrogen control during welding, according to FHWA.