Interstate 40 Hernando DeSoto BridgeShelby County
*The I-40 Mississippi River Bridge is open. The eastbound lanes reopened on July 31. The westbound lanes reopened on August 2.*
On May 11, 2021, a mechanical fracture was discovered during a routine inspection of the I-40 Mississippi River Bridge, also known as the Hernando DeSoto Bridge. The fracture, or crack, is in a steel support beam that is critical to the structure of the bridge.
Upon discovery of the fracture, the bridge was shut down to all traffic above and below the structure to ensure the safety of the motoring public along the interstate, as well as vessels traveling along the Mississippi River. The closure will allow for an extensive investigation into the cause, extent, and repair of the bridge.
At this time, it is unclear how long the bridge will remain closed to traffic. Detours are in place in Tennessee and Arkansas. To help you plan ahead, estimated average travel delays for the week will be posted here every Monday so you can see which days and times to avoid. You can also view real-time digital message signs.
Real-time I-55 Southbound Message Board in Arkansas prior to the I-40/I-55 interchange
Real-time I-40 Eastbound Message Board in Arkansas prior to the I-40/I-55 interchange
Real-time I-55 Northbound Message Board in Tennessee prior to South Parkway (Exit 10)
Originally built in the late 1960s to early 1970s, the Interstate 40 Mississippi River Bridge, also known as the Hernando DeSoto Bridge, is a steel-tied arch structure carrying interstate traffic across the Mississippi River between West Memphis, Arkansas, and Memphis, Tennessee. This bridge is a vital transportation, commerce, and defense link, being one of only two crossings of the Mississippi River in the Memphis area. It carries approximately 60,000 vehicles daily.
The bridge has a total length of 3.3 miles, including the main channel spans, approaches, and ramps. It’s comprised of 164 spans, 160 piers, and 10 abutments. The main channel spans consist of five steel-box girder spans (2 @ 330’ and 3 @ 400’) and two steel-tied arch truss spans (2 @ 900’). The west approach to the channel spans is primarily precast prestressed concrete I-girder spans and steel plate girder spans, while the east approach and connecting ramps are entirely welded steel-plate girder spans.
The arch truss spans are above the roadway and connected with steel box beams. A steel box beam is comprised of two side plates, measuring 32” x 1-3/8” (inboard and outboard), and tow cover plates, measuring 25” x 1/2” (top and bottom). A mechanical fracture, or crack, was discovered within the elements of a steel box beam on May 11, 2021. The fracture impacts 100% of the outboard plate, 100% of the top plate, and approximately 20% of the bottom plate.
The bridge is undergoing intense analysis, including bridge modeling, to determine the extent of the damage. As of May 14, 2021, there is no indication that the bridge is continuing to deteriorate. Additional modeling and analytical tools will be used to ensure quality control before making a final determination on structural stability. Design teams are working on short- and long-term solutions that would allow traffic to safely resume on the bridge.
Following the completion of repairs, the damaged steel will be preserved for detailed forensic investigation.
Diagram of I-40 Hernando DeSoto Bridge Identifying Location of Fracture
Video: Animated rendering of the planned repairs for the I-40 Hernando DeSoto Bridge
The Tennessee Department of Transportation (TDOT) and the Arkansas Department of Transportation (ARDOT) share responsibility for the Hernando DeSoto Bridge. ARDOT is responsible for routine and special inspections. TDOT is responsible for maintenance and repairs.
An ARDOT-hired contractor with Michael Baker International discovered a mechanical fracture in a steel support beam during a routine inspection on Tuesday, May 11, 2021. Local law enforcement agencies were immediately notified to shut down the bridge to all traffic above and below the structure.
TDOT and ARDOT are working together to evaluate the damage and determine the best solution. The bridge reopened to river traffic on Friday, May 14, 2021. The bridge will remain closed to interstate traffic until the bridge is deemed safe for travel.
Alternate Mississippi River Crossings
I-40 is a major artery through the center of America with one of the highest truck traffic percentages in the United States. I-40 runs through Memphis and crosses the Mississippi River, making Memphis a major transportation and economic center. The I-40 Hernando DeSoto Bridge is one of only two river crossings in the Memphis area. The other is the I-55 Mississippi River Bridge, which was built in the mid-1940s. I-40 provides for much of the nation’s east-west interstate trucking traffic and I-55 accommodates north-south traffic.
The next closest crossings over the Mississippi River are located approximately 85 miles away on I-155 between Missouri and Dyer County, Tennessee, north of Memphis, and on U.S. 49 between Helena, Arkansas, and Mississippi, south of Memphis.
Currently, all interstate traffic in the Memphis area is being diverted to I-55 until the Hernando DeSoto Bridge can be reopened safely to traffic.
The Hernando DeSoto Bridge is situated at the southeastern edge of the New Madrid Seismic Zone, where three of the largest earthquakes in the Central United States occurred in the early 1800s. Considering the potential for another major earthquake, TDOT partnered with ARDOT in the early 1990s to begin the seismic retrofit of the bridge.
Construction began in 2000 and continued through 2015, at a cost of $268.4 million. As part of the nine phases of construction, the deteriorated west approach was completely replaced with a new steel plate girder structure. All construction work was done while maintaining traffic.
This seismic retrofit project addressed areas vulnerable to seismic events by strengthening foundations and other elements. The work will allow the bridge to be able to withstand a 7.7 magnitude earthquake and provide a "post-earthquake" lifeline link for emergency vehicles and the general public.
No modifications were made to the area where the fracture was found on May 11, 2021.