The Hernando de Soto Bridge is a

tied-arch bridge A tied-arch bridge is an arch bridge in which the outward horizontal forces of the arch(es) caused by tension at the arch ends to a foundation are countered by equal tension of its own gravity plus any element of the total deck structure such grea ...

carrying

Interstate 40 Interstate 40 (I-40) is a major east–west Interstate Highway running through the south-central portion of the United States. At a length of , it is the third-longest Interstate Highway in the country, after I-90 and I-80. From west to ea ...

across the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it fl ...

between

West Memphis, Arkansas West Memphis is the largest city in Crittenden County, Arkansas, United States. The population was 26,245 at the 2010 census, ranking it as the state's 18th largest city, behind Bella Vista. It is part of the Memphis metropolitan area, and is ...

, and

Memphis Memphis most commonly refers to: * Memphis, Egypt, a former capital of ancient Egypt * Memphis, Tennessee, a major American city Memphis may also refer to: Places United States * Memphis, Alabama * Memphis, Florida * Memphis, Indiana * Memp ...

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

. The design is a continuous cantilevered cable-stayed steel through arch, with bedstead endposts. Memphians also call the bridge the "New Bridge", as it is newer than the

Memphis & Arkansas Bridge The Memphis & Arkansas Bridge, also known as the Memphis–Arkansas Bridge or inaccurately as the Memphis–Arkansas Memorial Bridge, is a cantilevered through truss bridge carrying Interstate 55 across the Mississippi River between West Memphis ...

(carrying

Interstate 55 Interstate 55 (I-55) is a major Interstate Highway in the central United States. As with most primary Interstates that end in a five, it is a major cross-country, north–south route, connecting the Gulf of Mexico to the Great Lakes. The h ...

) downstream, and the "M Bridge", due to its distinctive shape. It is of similar construction to the

Sherman Minton Bridge The Sherman Minton Bridge is a double-deck through arch bridge spanning the Ohio River, carrying I-64 and US 150 over the river between Kentucky and Indiana. The bridge connects the west side of Louisville, Kentucky to downtown New Albany, In ...

between

Louisville, Kentucky Louisville ( , , ) is the largest city in the Commonwealth of Kentucky and the 28th most-populous city in the United States. Louisville is the historical seat and, since 2003, the nominal seat of Jefferson County, on the Indiana border ...

, and New Albany, Indiana.

History

Preliminary planning for the river crossing began in 1960 as part of

alignment studies for the Memphis - Little Rock corridor, which was constructed in segments between 1963 and 1968. Before the Hernando de Soto Bridge was completed, traffic going across the river was carried across the Mississippi River by the Interstate 55/US Highway 64/70/79/61

crossing, located southwest. The two states initially feuded over the cost of paying for the bridge. Tennessee officials believed that both states should equally pay for the bridge, while Arkansas officials wanted Tennessee to shoulder a larger share of the cost due to its larger population. Both states eventually agreed to a compromise where Tennessee funded 60% of the cost and Arkansas the remaining 40%. Both states also initially disagreed on the design of the bridge; the original design called for longer through arches and a lower vertical clearance. Construction of the Hernando de Soto Bridge began on May 2, 1967. Initially planned for completion in 1971, the project experienced multiple delays. The double-arch bridge was opened to automobile traffic on August 2, 1973. A dedication ceremony for the bridge occurred on August 17, 1973. Initially expected to be only $12 million (equivalent to $ in ), the final price tag was approximately $57 million (equivalent to $ in ). The bridge is named for 16th century Spanish explorer Hernando de Soto, who explored this stretch of the Mississippi River and died south of Memphis.

Bridge illumination

At night, the bridge was illuminated by 200 sodium vapor lights along its "M" structure. The bridge was first illuminated on September 5, 1986, after $373,000 of private funds had been raised to fund the cost and installation of the lights. Due to some river traffic having issues with the lights at night reflecting on the water, the city installed a remote switch to toggle the lights on and off briefly while the vessel passes under the bridge. During the

2011 Mississippi River floods Major floods along the Mississippi River in April and May 2011 were among the largest and most damaging recorded along the U.S. waterway in the past century, comparable in extent to the Great Mississippi Flood of 1927 and Great Flood of 1993. ...

, the bridge became dark for about 2 months because the transformers that supply the electricity for the lights were removed to prevent damage to them by flood waters. The bridge was re-lit in a ceremony which occurred on June 21, 2011. It was announced after the opening of the Big River Crossing along the

Harahan Bridge The Harahan Bridge is a cantilevered through truss bridge that carries two rail lines and a pedestrian bridge across the Mississippi River between West Memphis, Arkansas, and Memphis, Tennessee. The bridge is owned and operated by Union Pacific ...

to the south that the existing sodium vapor lights along the Hernando Desoto Bridge would be replaced with a new LED lighting display, thus making the Hernando de Soto Bridge the second bridge over the Mississippi River to be lit as such after the Harahan. The new display can be lit in sync with the Harahan Bridge and display various color patterns dependent upon special occasions or requests. Both displays have been created under an initiative called "Mighty Lights." The $14 million privately funded project was completed in 2018.

Seismic retrofit project

Between 2000 and 2015, the bridge underwent a seismic retrofitting project, allowing it to withstand a 7.7 magnitude earthquake, the similar magnitude of earthquakes during the 1811–12 New Madrid earthquakes. The retrofit project is also a means to protect the bridge as it is located within of the

New Madrid Seismic Zone The New Madrid Seismic Zone (), sometimes called the New Madrid Fault Line, is a major seismic zone and a prolific source of intraplate earthquakes (earthquakes within a tectonic plate) in the Southern and Midwestern United States, stretching t ...

and serves as a major cargo route and traffic thoroughfare across the river. As part of this project, the main span, approaches, and ramps for the downtown exit were retrofitted. A bridge about west of the main span was rebuilt with earthquake considerations in mind. The federal government covered 80% of the cost, with Tennessee contributing 12% and Arkansas 8%.

Incidents

On August 23, 2007, an inspector discovered that a bridge pier on the approach bridge west of the river had settled overnight, and the bridge was subsequently closed to perform a precautionary inspection. The bridge was reopened later that day. On May 11, 2021, an inspection discovered a partially fractured tie girder on the Span A North truss. Two of the four plates comprising the box-shaped tension tie member were completely fractured and the bottom plate was partially fractured, leaving only the inside-facing plate intact. Since the severely compromised girder was one of a pair of load-bearing tension members that were critical to the structural integrity of the bridge's tied-arch design, the bridge was structurally unsound and at risk of collapse. The inspecting engineer called 9-1-1 and told authorities to shut down the bridge immediately. Traffic across and under the bridge was halted indefinitely while engineers inspected the rest of the bridge for other issues, and analyzed the structure. River traffic under the bridge resumed on May 14. Initial repairs that affixed steel plates on both sides of the affected girder were completed on May 25. The second phase consisted of the installation of additional steel plating and removal of part of the damaged beam. A new inspection of the bridge found "nothing of concern". The eastbound lanes reopened on July 31, 2021, the westbound lanes on August 2, 2021. During the closure, vehicle traffic utilized the nearby

(

I-55 Interstate 55 (I-55) is a major Interstate Highway in the central United States. As with most primary Interstates that end in a five, it is a major cross-country, north–south route, connecting the Gulf of Mexico to the Great Lakes. The h ...

) as an alternate route in the Memphis area, as well as the

Caruthersville Bridge The Caruthersville Bridge is a single tower cantilever bridge carrying Interstate 155 and U.S. Route 412 across the Mississippi River between Caruthersville, Missouri and Dyersburg, Tennessee. It is the only bridge that connects Missouri and T ...

( I-155) to the north and the

Helena Bridge The Helena Bridge is a cantilever bridge carrying U.S. Route 49 across the Mississippi River between Helena, Arkansas and Lula, Mississippi. The main cantilever span was modeled on the similar Benjamin G. Humphreys Bridge which had been bui ...

( US 49) to the south as alternates elsewhere in the Mid-South. Investigators received amateur photos taken from the river below as early as 2016 that already showed damage at the same site. And according to the

Arkansas Department of Transportation The Arkansas Department of Transportation (ArDOT), formerly the Arkansas Highway and Transportation Department, is a government department in the U.S. state of Arkansas. Its mission is to provide a safe, efficient, aesthetically pleasing and e ...

, review of archived drone footage taken during a May 2019 bridge inspection, two years before the damage was discovered, also showed the fracture. The department further found that the mandated hands-on—that is, within arm's length—inspections that should have occurred every two years had not been undertaken. The responsible inspector was subsequently fired. An engineering analysis revealed the fracture was the result of two particularly wide and poorly done weld repairs in the same spot during "fabrication" (construction) that, along with other poor welds elsewhere on the bridge, had been identified and repaired; there were consequently no further concerns.Arkansas Department of Transportation. "I-40 Hernando deSoto Bridge – Fracture Investigation"
PDF
Key findings of the report included the following four points:

Gallery

File:HernandoDeSoto Bridge from Martyr's Park.JPG, Hernando de Soto Bridge from Martyr's Park in Memphis File:HernandoDeSotoBridge_at_Night.jpg, Hernando de Soto Bridge illuminated at night File:Hernando De Soto Bridge Memphis TN 018.jpg, Crossing into Memphis on the Hernando de Soto Bridge

References

External links

* {{Memphis, Tennessee Through arch bridges in the United States Landmarks in Tennessee Bridges over the Mississippi River Bridges in Memphis, Tennessee Bridges completed in 1973 Buildings and structures in West Memphis, Arkansas Transportation in Crittenden County, Arkansas Road bridges in Tennessee Road bridges in Arkansas Interstate 40 Bridges on the Interstate Highway System Interstate vehicle bridges in the United States 1973 establishments in Arkansas 1973 establishments in Tennessee Tied arch bridges in the United States