What began as a routine overnight construction closure of southbound I-59/20 in downtown Birmingham, Ala., turned into a weeklong outage when an incomplete steel girder system shifted atop its temporary support structures.
On April 4, workers from Granite Construction Co. were installing 9.5-ft-tall, 65-ton girders for a new bridge at the I-65 interchange, part of the Alabama Dept. of Transportation’s three-phase, $750-million upgrade of I-59/20’s 45-year-old infrastructure. According to a Granite spokesperson, four girders being readied for splicing in the middle of the interchange were supported by two standard 100-kip shoring towers with 100 kip-per-leg capacity. The towers were erected on crane mats with welded steel stringer beams on the top and bottom. ALDOT says an apparent partial failure in one of the supports caused the girders to shift approximately 1 ft laterally and between 6 in. and 12 in. vertically.