Hernando de Soto Bridge
Hernando de Soto Bridge
|Carries||6 lanes of I-40|
|Locale||West Memphis, Arkansas, and Memphis, Tennessee|
|Other name(s)||The M Bridge, Memphis Bridge, Mississippi Bridge, New Bridge|
|Maintained by||TDOT and ARDOT|
|Design||tied arch, through arch|
|Total length||9,432.6 feet (2,875 m)|
|Width||90 feet (27 m)|
|Longest span||900 feet (274 m)|
|Clearance below||109 feet (33 m)|
|Construction start||May 2, 1968|
|Opened||August 2, 1973|
|Daily traffic||37,308 (2018)|
The Hernando de Soto Bridge is a through arch bridge carrying Interstate 40 across the Mississippi River between West Memphis, Arkansas, and Memphis, Tennessee. 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 (carrying Interstate 55) downstream, and the "M Bridge", due to its distinctive shape. It is of similar construction to the Sherman Minton Bridge between Louisville, Kentucky, and New Albany, Indiana.
On May 11, 2021, traffic across the bridge was halted indefinitely after a crack had been found on part of the bridge's load carrying structure.
Preliminary planning for the river crossing began in 1960 as part of Interstate 40 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 Memphis & Arkansas Bridge crossing, located 2 miles (3.2 km) 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, 1968. 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 only cost $12 million (equivalent to $68.7 million in 2021), the final price tag was approximately $57 million (equivalent to $256 million in 2021).
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.
At night, the bridge was illuminated by 200 sodium vapor lights along its "M" shape 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, 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 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 100 miles (161 km) of the New Madrid Seismic Zone, serves as a major cargo route, and traffic thoroughfare across the river. Work is being completed as funds are available. As part of this project, the main span, approaches, and ramps for the downtown exit are being retrofitted. A bridge about 1 mile (1.6 km) west of the main span was rebuilt with earthquake considerations. As the main span (the "M" portion) is located entirely within Tennessee, the funding formula was split 60%/40% between TDOT and AHTD. To date, $175 million has been spent with another $80 million expected.
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 led by Michael Baker International revealed that a crack had formed on the bottom of the tie girder at Span A North truss. According to ArDOT, review of a May 2019 bridge inspection using drone footage showed visible damage at the area near the crack. The responsible inspector was subsequently fired by ArDOT. Amateur footage from 2016 also showed damage in the same area. Traffic across and under the bridge has been halted indefinitely while engineers inspect the rest of the bridge for other issues, analyze the structure and fix the issue. According to TDOT and ARDOT officials, it is unclear as to when the structure can reopen to traffic. Vehicle traffic is utilizing the Memphis & Arkansas Bridge (I-55) as an alternate route in the Memphis area, as well as the Caruthersville Bridge (I-155) and Helena Bridge (US 49) as alternates elsewhere in the Mid South. River traffic was initially halted but resumed on May 14.
Repairs involving affixing steel plates on both sides of the affected girder were completed on May 25, 2021 with additional repairs still under way. A new inspection of the bridge found "nothing of concern".
- Transport portal
- Engineering portal
- United States portal
- List of crossings of the Lower Mississippi River
- Tennessee Department of Transportation. "Traffic History". ArcGIS. Esri. Retrieved July 18, 2020.
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- "I-40 bridge closed indefinitely after crack discovered in structure". WMC Action News 5. May 11, 2021.
- "Drone footage from 2019 reveals I-40 bridge damage, officials confirm". thv11.com. Retrieved June 15, 2021.
- Staff, WMC Action News 5. "Inspector who overlooked crack in 2019 bridge inspection terminated, ArDOT says". www.wmcactionnews5.com. Retrieved June 15, 2021.
- Peterson, Joyce. "Photos show I-40 bridge damage in 2016". www.wmcactionnews5.com. Retrieved June 15, 2021.
- "I-40 Hernando de Soto bridge over the Mississippi River is closed because of a crack in the bridge". Local 24. May 11, 2021.
- "Potential 'catastrophic event' avoided by routine I-40 bridge inspection, officials say. Reopening timeline unclear". Memphis Commercial Appeal. May 12, 2021.
- "Cracked Memphis Bridge Remains Indefinitely Closed, Disrupting Supply Chain". NPR.org. May 12, 2021. Retrieved May 13, 2021.
- "Closure of the I-40 Mississippi River Bridge". Arkansas Department of Transportation. Retrieved June 15, 2021.