Cracking Damage/Deterioration and Rehabilitation Considerations of Some Birmingham, Alabama, Interstate Bridge Decks

The Alabama Department of Transportation (ALDOT) has more than 4830 m of major Interstate bridges (three to five lanes wide) near downtown Birmingham, Alabama, that have significant levels of deck cracking and deterioration. The bridges are part of the Interstate 65 and Interstate 59 highway system through the city and are approximately 27 years old. It appears that deck cracking is primarily the result of (a) early drying and thermal shrinkage, (b) early concrete obstructed settlement, (c) thin and flexible decks, (d) light and flexible superstructures, and (e) heavy traffic volume and loadings. The deck condition versus age and the crack classification/width versus age curves are presented for three typical bridge decks, along with a photographic portrayal of the state of deck cracking and deterioration. Comparisons of experimental and theoretical load deflection behavior of two of the bridges are presented. The rehabilitation or replacement of the bridge decks that are approximately 55 740 M² is a matter of great concern to ALDOT. Actions the agency is currently taking and actions it plans to take are also presented.