Corven Engineering, a Hardesty & Hanover company, created the final design of the precast segmental superstructure for new bridges on the heavily traveled Interstate 59 and Interstate 20 through downtown Birmingham, AL. The new bridges replace steel plate girder bridges built in the early 1970s and carried up to five travel lanes and shoulders in both the eastbound and westbound directions.
Precast segmental concrete bridges were the only option that could be erected within the 14-month closure time mandated by ALDOT. It allowed for offsite precasting of the bridges prior to the Interstate closures with fast erection times. The precast segmental concrete option also offered other benefits to ALDOT: increase span lengths, improved durability, and aesthetics.
Additionally, the new bridges were placed in the same footprint as the original bridges. New columns were strategically located during design to avoid the original columns. This allowed work to begin on the substructure of the new bridges prior to the closure of the Interstates.