Hernando de Soto Bridge

On May 11, 2021, a partial fracture of a tie girder on the arch span of the Hernando de Soto Bridge over the Mississippi River between Memphis and West Memphis, Ark., was discovered during a fracture-critical inspection, requiring immediate closure of highway and river traffic.

The challenge was to stabilize the bridge and have construction crews safely repair it to allow traffic to resume. The team used a three-phase approach and conducted nondestructive testing on all tie girder welds to determine other locations for retrofit while the first two phases were ongoing. The three phases were stabilization, member repair, and overall tie girder repair, with the design and construction of each overlapping. This required the collaboration of two owners, two engineers, a contractor, and multiple fabricators. All parties adjusted the approach to meet daily needs and changing conditions. Activities progressed 24 hours a day, supported by extended shifts, for several weeks, and the bridge reopened in just 83 days.

Design, fabrication, and construction were all-day efforts. The design of stabilization repairs was completed within days of testing, then fabrication and construction commenced immediately. The project included three fabricators providing steel, all synced to the contractor’s schedule, and the design was tailored for materials available “on the floor” from shops that had advised on the best materials to aid with efficiency. There were no significant RFIs, a testament to design quality and fabricated structural steel.

To reduce the costly closure time, repair plans were designed around available materials. Michael Baker worked with NSBA and the fabricators to locate the HPS70 steel to replace 100-ksi material for Phase 1 and Phase 2 repairs. Simplifying the bolted splice details and the use of high-performance steel led to efficient fabrication and erection, resulting in the shortened closure, and similar details were repeated during Phase 3 repairs to other identified locations in the bridge.

Project Team

• Steel Fabricators and Detailers:

  • W&W | AFCO Steel, Little Rock *AISC CERTIFIED*

  • Stupp Bridge Company, Bowling Green, Ky *AISC CERTIFIED*

• Owners:

  • Tennessee Department of Transportation

  • Arkansas Department of Transportation

• General Contractor: Kiewit Infrastructure South Co.

• Structural Engineer: Michael Baker International, Inc.