The I-64 Sherman Minton Bridge was closed to traffic on Sept. 9 after inspectors discovered a crack in the bridge’s superstructure. The bridge consists of two 800-ft tied arch truss main spans that carry six lanes across the Ohio River between Louisville, Ky., and New Albany, Ind. It was constructed in 1960-61 using T-1 steel, before the material and fabrication requirements of the AASHTO/AWS Fracture Control Plan for this type of bridge were adopted.
Several cracks were found during routine inspections of the fracture-critical bridge earlier this year in the butt welds or their associated heat-affected zones of the tension ties of both spans. It was subsequently determined that the cracking was very likely caused by hydrogen that was introduced into the weld as the result of improper fabrication procedures. T-1 steel is known to be very susceptible to this type of cracking.
Retrofit and repair work began earlier this year.
Inspectors discovered an additional critical crack on Sept. 8 in the tension tie that previously could not be seen through visual inspection because of the removal of a connection plate detail as part of the ongoing retrofit process. Authorities determined that an unacceptable level of risk to the traveling public was associated with the continued operation of the bridge.
The Federal Highway Administration issued a technical advisory on Sept. 12 strongly recommending that “state DOTs and other bridge owners review the inspection records of their inventory of fracture-critical bridges to ensure any components fabricated with T-1 steel have been regularly and appropriately inspected and that any critical findings have been properly identified and addressed.”
Transportation and law enforcement officials from Kentucky, Indiana and local governments worked quickly to shepherd an extraordinary volume of detoured traffic on Monday, Sept. 12, the first work day following closure of the I-64 Sherman Minton Bridge.
Officials used a variety of tools to keep traffic flowing, including:
- Ramp and lane restrictions at critical junctions of I-64, I-65 and I-71;
- Reversible lanes on Clark Memorial Bridge;
- Altered timing for traffic signals on local streets;
- Extra police officers, traffic-management crews and emergency responders; and
- Electronic message boards to inform motorists of traffic changes and restrictions.
“The key to success is cooperation of the driving public to spread out the traffic flow,” said Kentucky Transportation Secretary Mike Hancock. “But we will continuously monitor traffic and make adjustments as necessary.”
A centerpiece of the traffic plan is the use of reversible lanes on Clark Memorial Bridge, providing three lanes for southbound traffic during the morning rush and three lanes of northbound traffic during afternoon rush.
The Kentucky Transportation Cabinet is advising motorists to “leave home or the workplace earlier or later than usual. They should carpool or telecommute or avoid interstate routes when possible. And above all, they should be patient.”