The newest of the bridges that span the lower Mississippi
River at Memphis, the Hernando de Soto Bridge was completed in 1973 and carries
Interstate 40 between downtown Memphis and West Memphis, AR. The bridge’s
signature M-shaped superstructure makes it an instantly recognizable landmark
in the city and one of the most visually unique bridges on the Mississippi
River.
As early as 1953, Memphis city
planners recommended the construction of a second highway bridge across the
Mississippi River to connect the city with West Memphis, AR. The Memphis &
Arkansas Bridge had been completed only four years earlier a couple miles downriver
from downtown, however it was expected that long-term growth in the metro area
would warrant the construction of an additional bridge, the fourth crossing of
the Mississippi River to be built at Memphis, in the not-too-distant future. Unlike
the previous three Mississippi River bridges to be built the city, the location
chosen for this bridge was about two miles upriver from the
Frisco/Harahan/Memphis & Arkansas trio of bridges, at an outcropping known
as Mud Island, across from downtown Memphis. The project received a critical
boost when in 1956, the Federal Aid Highway Act created the national system of
interstate highways and the newly-formed Interstate 40 freeway was designated
to run east-west across greater Memphis, utilizing the planned bridge at Mud
Island.
With federal funding assured due to the proposed bridge’s location on the interstate system, construction began in 1967. There were initial disagreements between the states of Tennessee and Arkansas as to how the project’s state-level funding would be split between them. Tennessee argued for a 50-50 share of responsibility, however Arkansas argued that Tennessee would see far greater benefit from the project economically and advocated for a 67-33 split in favor of Tennessee. In the end, a compromise agreement was reached where Tennessee agreed to a majority 60-40 stake in its construction in exchange for Arkansas assuming primary responsibility for the bridge’s maintenance post-construction.
Spanish explorer and conquistador Hernando de Soto (c.1500-1542) is known as the first European to lead an expedition through the region known today as the Mississippi Delta.
After multiple years of delays and cost overruns, the new I-40 Bridge opened to traffic on August 2, 1973 after nearly six years of construction. The bridge was named in honor of Spanish conquistador Hernando de Soto, who led the first European expedition in an exploration of the American southeast and the Mississippi Delta in the early 1540s. The bridge’s overall length is nearly two miles, as the elevated structure crosses the Mississippi River and its adjacent flood plains on both sides. The centerpiece of the bridge is it’s M-shaped arch design, which gives the bridge its distinctive appearance. The two main arch spans are 900 ft apiece and the structure supports a six-lane freeway that serves as one of the most important highways in the American south. A large interchange is located at the east end of the main span above Mud Island, where unfinished ramp stubs exist that were intended to connect the bridge with a never-completed ”Mud Island Expressway”, a freeway that would have run from Riverside Drive in downtown northward to the US Highway 51 corridor in North Memphis before ending at the northwest corner of the Memphis Loop (Interstate 40). This freeway proposal was quietly shelved in the 1980s and the short freeway spur that connects I-40 with US 51 at Exit 2A (and part of the future I-69 corridor across western Tennessee) was the lone fragment of this highway that was ever built.
The Hernando de Soto Bridge was emptied of all traffic in this May 2021 photo. The long-term closure of the bridge and adjacent Interstate 40 received national attention at a time when the condition of the nation's infrastructure was under greater scrutiny.
Due to the bridge’s unique M-shaped superstructure, this
bridge is sometimes known as the Memphis Bridge or the “M-Bridge” by locals. With
the recent realization of the potential of the New Madrid Seismic Zone, federal
and state officials secured funding for sweeping upgrades to the structure’s
support system that are aimed at making the bridge more resilient to powerful
earthquake events. The most substantial of these upgrades to date has been the
replacement of the bridge support bearings with pendulum isolation bearings.
These newer bearings isolate the road deck from the support structure below,
enabling it to shake independently of the substructure, reducing the risk of
catastrophic failure of the support system. About $70 million has been invested
since the 1990s for this seismic retrofit program, as of 2023. It is estimated
that the de Soto Bridge is now engineered to withstand earthquake shaking of
about M7.0 on the Richter Scale. It is hoped that we will never need to find
out the accuracy of this statement.
The bridge gained national attention in May 2021 when a routine inspection discovered a complete fracture of a longitudinal edge girder beneath the roadway at the bridge’s main span. The bridge was immediately closed to all traffic as the situation was assessed and repairs were made to shore up the structure. The de Soto Bridge’s superstructure was designed with multiple redundancies built into its support system, so this local failure thankfully did not translate into a catastrophic collapse. Temporary repairs were completed in August and the bridge reopened to traffic that month, however the traffic nightmare that played out in the Memphis area that summer received national attention due to the high visibility of the corridor in question. The inspection team affiliated with the Arkansas Department of Transportation (ARDOT) came under intense scrutiny in the aftermath of the discovered fracture when it was revealed that the damaged girder had gone unnoticed by prior inspections as far back as 2019. The systemic breakdown in the maintenance & inspection procedures at this bridge is disturbing to say the least and it has hopefully led to the reassessment of procedures nationwide and the implementation of improved methods that will keep our bridge inspectors vigilant and our bridges safe for the public’s use.
Bridges, Crossings, and Structures of the Lower Mississippi River
Next Crossing upriver: Caruthersville Bridge (Caruthersville, MO)
Next Crossing downriver: Harahan Bridge/"Big River Crossing" (Memphis, TN)
Visit the Mississippi River Bridges of Memphis Overview Page
Return to the Bridges of the Lower Mississippi River Home Page
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