Metallurgical analysis, including oxidation testing, indicated the crack dates from the early 1960s, when the bridge was constructed. Prior to the repairs, the crack was concealed by a connection plate.
Following the closure, non-destructive testing, including ultrasound and radiography, led to the discovery of six additional cracks in similar locations. INDOT closed the bridge until repairs were completed. According to the FHWA advisory, “several cracks were found in the butt welds or heat-affected zones of the tension ties of both spans.”
A planned six-month, $20-million repair program involves bolting steel plates along the entire length of the ties, an approach that calls for 2 million lb of new steel and 71,000 new bolts, according to bidding documents issued by INDOT.
“Short of a complete replacement, this is about as forceful a response as what was [available] on the menu,” Indiana Gov. Mitch Daniels (R) stated during a Sept. 30 press conference in New Albany, Ind. FHWA will contribute $5 million for repairs, with the remaining costs to be split between Indiana and Kentucky.
Bids, which must be submitted by Oct. 18, will be evaluated on the basis of cost and how quickly repairs can be implemented, according to INDOT spokesman Will Wingfield. “An incentive of $100,000 will be available for each day the winning bidder finishes early, with a cap of $5 million,” he says.
Sherman Minton, one of three spans connecting southern Indiana with Louisville, carries up to 80,000 vehicles per day. The bridge gained national attention in September when Transportation Secretary Ray LaHood toured the structure and used his appearance to tout President Obama's American Jobs Act, which calls for creating jobs with transportation and infrastructure projects.