Rating:
4 votes

Hernando DeSoto Bridge

Photos 

Overview at dark

Photo taken by Jeremy Clevenger

BH Photo #108921

Map 

Street Views 

Facts 

Overview
Two-span steel through arch bridge over the Mississippi River on I-40 at Memphis
Location
Memphis, Shelby County, Tennessee, and Crittenden County, Arkansas
Status
Closed due to a crack being found.
History
Built 1973
Builder
- Bethlehem Steel Co. of Bethlehem, Pennsylvania
Design
Two 900' tied steel arch spans and five continuous steel box girder spans
Dimensions
Length of largest span: 899.7 ft.
Total length: 9,432.6 ft. (1.8 mi.)
Deck width: 85.6 ft.
Vertical clearance above deck: 18.6 ft.
Also called
The New Bridge (common name)
"m" Bridge
Approximate latitude, longitude
+35.15307, -90.06403   (decimal degrees)
35°09'11" N, 90°03'51" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/767451/3893966 (zone/easting/northing)
Quadrangle map:
Northwest Memphis
Average daily traffic (as of 2018)
36,940
Inventory numbers
TN 79I00400001 (Tennessee bridge number)
BH 32700 (Bridgehunter.com ID)
Inspection report (as of September 2017)
Overall condition: Fair
Superstructure condition rating: Fair (5 out of 9)
Substructure condition rating: Good (7 out of 9)
Deck condition rating: Satisfactory (6 out of 9)
Sufficiency rating: 58 (out of 100)
View more at BridgeReports.com

Update Log 

  • May 12, 2021: New photo from Jeremy Ruble
  • May 11, 2021: Updated by J.P.: Crack found.
  • July 10, 2019: New Street View added by Dana and Kay Klein
  • December 20, 2016: New photos from Nathan Holth
  • July 8, 2016: New photos from Royce and Bobette Haley
  • February 28, 2014: New photo from Jack Schmidt
  • November 12, 2013: New photo from Shane Passmore
  • November 8, 2013: New photos from Shane Passmore
  • March 4, 2011: New Street View added by J.P.
  • April 1, 2009: New photos from Channin Rosenthal
  • June 3, 2008: New photos from David B. Haun
  • May 22, 2006: Posted additional photo from Jonathan Maxwell

Sources 

  • Jeremy Clevenger - j_s_clevenger [at] yahoo [dot] com
  • Jonathan Maxwell - themaxwellshouse [at] roadrunner [dot] com
  • Wikipedia
  • David B. Haun
  • Channin Rosenthal
  • J.P. - wildcatjon2000 [at] gmail [dot] com
  • Dana and Kay Klein
  • Shane Passmore - aa5te [dot] kb5ehr [at] gmail [dot] com
  • Jack Schmidt - jjturtle [at] earthlink [dot] net
  • Royce and Bobette Haley - roycehaley111 [at] yahoo [dot] com
  • Nathan Holth
  • Jeremy Ruble - jaruble1982 [at] gmail [dot] com

Comments 

Hernando DeSoto Bridge
Posted May 15, 2021, by Roger Deschner (rogerdeschner [at] gmail [dot] com)

News reports this morning say that Arkansas Department of Transportation officials knew about this developing crack as early as 2019, and they had drone footage showing the crack. There is also a civilian on a boat underneath the bridge who snapped photos of the developing crack in July 2019.

https://www.fox13memphis.com/news/local/confirmed-2019-video...

Keep in mind that in any tied arch bridge, the bottom chord, or tie, is under considerable tension. This good-looking bridge may ultimately be doomed, and its beloved "m" design may be part of its problem. There's another tied-arch bridge over the Mississippi at Davenport IA on I-280, built in the same era in 1970, that is now rated "serious" in its latest inspection. It too, should be subject to much closer inspection.

Art S. mentioned the possible role of extreme cold weather, in February 2021. Extreme cold has been cited in several other bridge failures, such as the Hoan Bridge in Milwaukee and the Lake Shore Drive Drawbridge approach span in Chicago.

Hernando DeSoto Bridge
Posted May 14, 2021, by Art S. (Asuckewer [at] knite [dot] com)

Nathan,

Interesting speculation from an engineering professor local to and familiar with the bridge

Something is odd with the explanation given by the professor in the link. The arch itself is trussed and the tie, which supports the deck, is supported by the arch through cables, not a truss web, while keeping the ends of the arch together.

The loading through the cables is purely tensile (pulling along their length). The uneven loading of the cables due to varying length is an obvious design characteristic, similar to that of suspension bridges. In fact the cable stayed suspension bridges (Roebling designs having both radiating stays and vertical suspenders - e.g. Brooklyn Bridge) have a similar indeterminate nature that couldn't be calculated without computers. The difference is the Roebling design has greater elasticity and is more tolerant of improper adjustment. This bridge's bow and tie are more rigid by comparison.

Even though there is an indeterminate element to the loading its not black magic and engineers that designed it would have understood this. To adjust for the uneven cable length they would set the pre-tension differently for each cable along the bridge, making assumptions for the dead and live loads and other variables.

I still say the break resulted from improper maintenance. If the cables had not been checked to determine if the tensioning adjustment was still correct and within design spec. there may have been an imbalance. That would have created a localized stress issue that could be an order of magnitude greater than what the professor is talking about.

I froze video and read the section of report shown. It indicated that the metal was largely fine but it seemed to point to a bit of sloppiness with maintenance - the drains were perpetually clogged.

They seemed to be keeping an eye on the condition of things (spalling, deck cracking, rust, etc.) and would fix things only after they deteriorated past a certain point.

The newscast mentioned the professor put seismic instrumentation on the bridge for a 2015 study. It would be interesting to learn what that study showed and if the instrumentation was left in place for continuous monitoring. With adequate instrumentation and correct placement, the data from the sensors could reveal the tensioning across the cables and possibly show actual stress concentrations from improper tensioning. Frankly, if the instrumentation was in place and recording, it should have detected the moment the tie broke.

The other thing that caught my attention was that the last inspection was done 9 months ago and it showed the metal was fine. It got me thinking: was there anything in the past 9 months that would have exacerbated whatever was going on? I realized there was a significant event! This past winter's southern deep freeze. Remember the frozen windmills in Texas? I'll bet the bridge got unusually cold too! If so, and the stresses were not correctly distributed due to poor adjustment, or the bearings were seized, the thermal shrinkage would have had a significant effect on the resulting stress concentration.

I wonder if the tie snapped during the winter freeze - due to my theory or because the cold did something else.

Regards,

Art S.

Hernando DeSoto Bridge
Posted May 14, 2021, by Mike Goff (michael [dot] goff [at] hotmail [dot] com)

That is an interesting theory for sure. Unequal cable elongation creating uneven stresses in the tie bars, maybe it cable stretch and not bearing movement... thanks for sharing.

No matter what the cause is, it will be interesting looking at these comments years from now and laughing at how wrong I was...

Hernando DeSoto Bridge
Posted May 14, 2021, by Nathan Holth (webmaster [at] historicbridges [dot] org)

I appreciate the speculation as I had been playing "guess the cause" myself but with a lot less experience. I found this article interesting too, another engineer just speculating too.

https://www.kait8.com/2021/05/13/engineer-examines-i-bridge-...

Hernando DeSoto Bridge
Posted May 14, 2021, by Mike Goff (michael [dot] goff [at] hotmail [dot] com)

Here is massive speculation based in real life experience with steel fractures in bridge members.

That crack is very likely the result of steel fatigue and expanded from very small cracks if not microscopic into full fracture in a relatively short amount of time. The short amount of time being between inspections. Though I would guess once it started growing visually it was a matter days or hours to full fracture.

The welded box design played significantly into the cracks rapid growth. A built up riveted section typically will not transfer a crack from one individual piece of steel into the next. Where a weld can transfer that crack from piece to piece in addition to being the root cause of many cracks.

If I really want to speculate, I will guess that the root cause will be one of or a combination of three sources of stress in no particular order. Fatigue from traffic loading, vibrations from lateral wind loads and/or some odd stresses steming from lack of proper movement at the bearings. These combined with some material defect in the welds or plates.

Well, that's a bunch of guesses that mean nothing to anyone. Sometimes it's fun to play bridge detective with nothing to go on but a picture.

Hernando DeSoto Bridge
Posted May 13, 2021, by Nathan Holth (webmaster [at] historicbridges [dot] org)

Keep in mind that the further you go into the 20th century, the more "advanced" engineering became. Especially by the time this bridge was built, computers began to play a role in design. Result: Engineering calculations could be completed with greater accuracy. These bridges tended to be less overbuilt than earlier bridges. While we may view bridges from this era as historic or attractive, they do in my opinion lack the durability that we see with earlier bridges such as the masterpiece works of Ralph Modjeski and George Morison located immediately south of this bridge.

Hernando DeSoto Bridge
Posted May 13, 2021, by Clark Vance (cvance [at] dogmail [dot] com)

Without interviewing the beam personally, I believe this did not happen suddenly. I'd be curious as to when it was last inspected and photos of how it looked at that time.

Hernando DeSoto Bridge
Posted May 12, 2021, by Art S. (Asuckewer [at] knite [dot] com)

Best reason to fix rather than replace - The Unibrow:

Hernando DeSoto Bridge
Posted May 12, 2021, by Art S. (Asuckewer [at] knite [dot] com)

never mind, all better:

Hernando DeSoto Bridge
Posted May 12, 2021, by Art S. (Asuckewer [at] knite [dot] com)

I dislike poor upkeep; it is waste. Excessive bureaucracy resulted in poor practices which led to inadequate monitoring/upkeep. This resulted in premature failure and tens of thousands of hours wasted by travelers and will probably trigger tens of millions of dollars of cost due to early replacement.

It will take two weeks to get through the red tape and about two days to fix. They are flying drones to look at it because they are scared to go out there but it was holding lots of 40 ton trucks in that condition...

In my opinion, for the bridge to actually collapse, the failure mode would be an uneven loading of the concrete piers in the center. This uneven load would be caused by the broken tie (the piece with the crack). The uneven load would then act on the concrete pier, causing the pier to crack and fail under a twisting force. The rest of the bridge should resist this from happening. This bridge is a Siamesed, tied arch design, the stresses on the bridge should pull the broken piece apart. That isn't happening in the pictures, so the immediate problem is probably not that bad. Actually, you might be able to realign the broken pieces by strategically placing heavily loaded trucks on the two spans on either side of the central pier.

The real issue is: what caused the break, why wasn't the problem identified earlier and are there other problems that have been missed. This bridge was opened in 1973 (Biden was in his first term in the Senate) it is a relatively modern design made of relatively modern materials. By comparison the Eads Bridge across the Mississippi in St. Louis opened in 1874 (U.S. Grant was President) and it was also recently temporarily closed - not due to structural issues but because of illegal street racing!

Unfortunately, the system is set up to build new, not maintain existing. The take away will not be: 'our monitoring and maintenance program needs to be improved, lets figure this out, then make sure the bridge remains like new going forward.' It will be: 'old bridge bad - need money for new bridge!'

Regards,

Art S.

Hernando DeSoto Bridge
Posted May 12, 2021, by Nathan Holth (webmaster [at] historicbridges [dot] org)
Hernando DeSoto Bridge
Posted May 12, 2021, by Brad Smith (gaberdine [at] hotmail [dot] com)

The bridge has a crack and is closed until further notice.

https://www.wmcactionnews5.com/2021/05/11/emergency-roadwork...

Hernando DeSoto Bridge
Posted October 27, 2015, by William Alford (wjalford [at] comcast [dot] net)

The bridge has 6 lanes 3-3 not 4, 2-2 with no brake down lanes

Hernando DeSoto Bridge
Posted August 13, 2015, by Cassie (greydelislefan [at] gmail [dot] com)

Eh, it probably isn't the best bridge in the world, but I like it myself. Upgrades or a twin span could be built to alleviate its issues, certainly.

Mississippi River I-40 Bridge
Posted April 1, 2009, by Channin Rosenthal

It does have 4 lanes even though there is no emergency lane. The bridges in Cairo, Illinois are WAY scarier!! I love this bridge, mostly because I live in Memphis and I remember when they put the lights on the bridge. Sentimental reasons I guess.

Mississippi River I-40 Bridge
Posted September 4, 2007, by tom

This bridge is almost as bad as the Brent Spence Bridge in Cincinnati but not that old. A Twin Structure ought to be built parallel to this one.

Mississippi River I-40 Bridge
Posted August 22, 2007, by Frank Sellke (franksellke [at] brueckenweb [dot] de)

a photo

Mississippi River I-40 Bridge
Posted August 3, 2007, by James (adorno423 [at] aol [dot] com)

67.30 Sufficirncy rating

Mississippi River I-40 Bridge
Posted August 3, 2007, by Beverly Hanna (bhanna [at] appliedfiber [dot] com)

What is the rating of this bridge as of August, 2007. I have always been afraid on this one and the collapse in Minnesota has not helped.

Mississippi River I-40 Bridge
Posted March 22, 2007, by jeff (gainesjt [at] gmail [dot] com)

There are no emergency pull-off lanes on this bridge. If a car stalls or stops for any reason, it stalls or stops in a traffic lane. There have been numerous crashes as a result of this deficiency. Many have resulted in fatalities. One crash, involving a DUI driver, sent a small child over the side of the bridge. He fell ~80' to his death.

Mississippi River I-40 Bridge-Appraisal: Functionally obsolete
Posted March 21, 2007, by Doug Force (dougforce [at] gmail [dot] com)

What does this mean?

Appraisal: Functionally obsolete

??

Thx