8 votes

Walnut Street Bridge


View from southeast

Photo taken by James Baughn

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BH Photo #108843

Street View 


Flyover from North to South

Video by Mark Boettcher

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Flyover from East to West

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Pardon the jerky flyaround

Video by Mark Boettcher

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Six-span Pennsylvania through truss bridge over the Tennessee River on Walnut Street in Chattanooga
Chattanooga, Hamilton County, Tennessee
Open to pedestrians only
Built 1889-91 by the Smith Bridge Company
- Edwin Thacher of New York City, New York (Chief Engineer)
- Neely Smith & Co. of Chattanooga, Tennessee (Substructure)
- Smith Bridge Co. of Toledo, Ohio (Fabricator and Contractor)
From south to north:
Two pin-connected, 10-panel Pennsylvania through trusses, each 210 feet long
Three pin-connected, 16-panel Pennsylvania through trusses, each 320 feet long
One pin-connected, 10-panel Pennsylvania through truss, 210 feet long
Wrought-iron curved viaduct, 780 feet long
(All trusses are 5-slope Camelback format)
Length of largest span: 320.0 ft.
Total length: 2,370.0 ft. (0.4 mi.)
Posted to the National Register of Historic Places on February 23, 1990
Also called
Hamilton County Bridge
Approximate latitude, longitude
+35.05817, -85.30729   (decimal degrees)
35°03'29" N, 85°18'26" W   (degrees°minutes'seconds")
Approximate UTM coordinates
16/654360/3880803 (zone/easting/northing)
Quadrangle map:
Inventory numbers
NRHP 90000300 (National Register of Historic Places reference number)
BH 32555 (Bridgehunter.com ID)

Update Log 

  • June 7, 2022: New video from Mark Boettcher
  • April 22, 2021: New photos from Geoff Hubbs
  • September 20, 2020: New photo from Glenn Celerier
  • July 12, 2017: New photos from Matt Dunmore
  • May 4, 2017: New photos from Chris Simmons
  • May 3, 2017: New photos from Chris Simmons
  • November 30, 2016: New photo from Andrew Penik
  • November 27, 2016: Updated by Christopher Finigan: Added category "Wrought Iron"
  • April 8, 2015: Photo imported by Dave King
  • March 2, 2014: New photo from Jack Schmidt
  • March 10, 2010: Updated by Eddie Douthitt: Added Google Street View
  • August 21, 2006: Posted all new photos


  • James Adorno
  • HAER TN-11 - Walnut Street Bridge
  • Wikipedia
  • Eddie Douthitt - dalton1861 [at] yahoo [dot] com
  • HAER TN-11 - Walnut Street Bridge, Spanning Tennessee River at Market Street, Chattanooga, Hamilton, TN
  • Historicbridges.org - by Nathan Holth
  • Jack Schmidt - jjturtle [at] earthlink [dot] net
  • Chris Simmons - atlanta_bulldog_red [at] yahoo [dot] com
  • Matt Dunmore
  • Calvin Sneed - us43137415 [at] yahoo [dot] com
  • Glenn Celerier - celerier [dot] bridgehunter [at] gmail [dot] com
  • Geoff Hubbs
  • Mark Boettcher


Walnut Street Bridge
Posted November 12, 2021, by Calvin Sneed (us43137415 [at] yahoo [dot] com)

I like the designation of Pennsylvania truss with a camelback format. Even Warren's have subtypes, too.

Walnut Street Bridge
Posted July 20, 2020, by Art S. (asuckewer [at] knite [dot] com)


Sorry for the delayed response. Apparently my initial response didn't load.

I have no problems with disagreements and welcome discussions. Writing my response cleared out some cobwebs in my memory banks :^)

I look forward to seeing your other photos and your input/insight.


There are many errors that can be perpetuated by being written down. The issue is: What was the basis of that chart. Its not wrong but was it industry standard terminology or is it what the guy who made the chart knew? The trick is getting general agreement on terminology for this site with the an aim of adopting the most commonly used terms. While I'm OK tying the truss types to that chart, I personally don't think its necessary.

To me, the original list is fine and correct for our purposes. If we start renaming the configurations, things will get confusing e.g. a Baltimore can also be called a subdivided Pratt or, according the same chart, a Petit.


Of course you'd find the oddball :^)

My understanding of the subdivided panel rigging is that it increases stability especially under a dynamic load.

One of the problems with a Pratt is how parts of the bridge take and release strain as the load travels across it. If the load (vehicle/horse/etc.) travels too fast, the strains can go negative in some panels causing instability and failure. Which is why the old bridges had signs that all said 'cross at a walk' or similar.

By subdividing the panels, the elements are stabilized and stay aligned even at increased length allowing higher static and dynamic loads. (think wheelie bars or axle straps on a hot rod).

I agree with you that a bridge with any panels that are subdivided should be in the Petit family (Baltimore/Pennsylvania).

Regards to all,

Art S.

Walnut Street Bridge
Posted July 18, 2020, by Tony Dillon (spansaver [at] hotmail [dot] com)

And certainly no disrespect meant to you Calvin!

Walnut Street Bridge
Posted July 18, 2020, by Tony Dillon (spansaver [at] hotmail [dot] com)

I have seen these dubbed as "Pennsylvania Truss-Camelback format". This is to differentiate them from the much more common Parker style (more than 5 slope) endpost/upper chord format. But slopes are not trusses, and it's just muddying the waters to say this is a Camelback... but yet it's a Pennsylvania. Throw Pratt together with either of those two and it makes sense.

The Black River Bridge in Posey County, IN is a Camelback with a sub-divided center panel: http://bridgehunter.com/in/posey/griffin-road/. All of the other panels are traditionally composed.

So I guess from a terminology standpoint there will always a level of dissension here. To me it is, and always will be, a Pennsylvania Truss.

Walnut Street Bridge
Posted July 18, 2020, by Calvin Sneed (us43137415 [at] yahoo [dot] com)

No problem, Art. I'm not trying to get into a disagreement. I've photographed hundreds of bridges that I have yet to post on Bridgehunter, several of them gone now.

I enjoy a healthy discussion with fellow bridge lovers.

Walnut Street Bridge
Posted July 18, 2020, by James Baughn (webmaster [at] bridgehunter [dot] com)

Stirring the pot some more...

According to the HAER poster of truss types, this is a "Camelback with subdivided panels". It's defined as "a Pennsylvania truss with a polygonal top chord of exactly five slopes." It's shown separately from the regular Pennsylvania truss.

I've never noticed that distinction before:


Walnut Street Bridge
Posted July 18, 2020, by Art S. (asuckewer [at] knite [dot] com)


I appreciate your desire for accuracy to the extent of checking with experts before posting. One of the interesting things you will encounter is that most engineers involved with bridges today deal in cable stays and pre-stressed concrete. They are true experts in these areas. Few of these engineers also have a deep knowledge of trusses.

An equivalent scenario is the engineers and crews that design, build and maintain modern railroads may not have the same knowledge of steam locomotive design and operation as they do about diesel-electric locomotives.

This is also why bridge enthusiasts are a bit of a thorn in DOTs' & DPWs' sides. We spout on poetically about these wonderful old structures in a similar manner to foamers going on about old engines. They want to get on with the business of transportation and are not necessarily knowledgeable about, or set up to maintain, these obsolete elements.

Its also the reason most of these old trusses are a genuine headache for these agencies.


Art S.

PS. I am in no way trying to pour cold water on your enthusiasm nor was what I wrote intended as any sort of attack. Why not google these designs yourself? The basic engineering of most trusses is quite straightforward. You can figure out the strains without an engineering degree.

PPS. I'd be curious to know what your friend/acquaintance at T-DOT would say if you shared this and my prior post with them.

Walnut Street Bridge
Posted July 18, 2020, by Calvin Sneed (us43137415 [at] yahoo [dot] com)

The note I received verbatim from the Regional Bridge Inspector with the Tennessee Department of Transportation, who confirmed the information with his supervisors at T-DOT, Nashville:

Calvin: Walnut Street is a pratt camelback. The approaches are just “riveted cross frame supports” or sometimes called a “rigid frame support”.

Let me know if you need any more information.

Art, I appreciate your descriptions. I will go with what the people who build and repair them tell me they are, and I withdraw anything I have put on this particular bridge. You all are free to call them whatever you feel is correct.

Walnut Street Bridge
Posted July 18, 2020, by Art S. (asuckewer [at] knite [dot] com)


Your understanding of truss types is incorrect, Tony is correct. This is a Pennsylvania.

A Pratt is a truss that has a simple web with diagonals in tension (being stretched) and verticals in compression (being squeezed).

A Parker is a Pratt (same loading characteristics + simple web) with a polygonal top chord (not flat between endposts).

A Camelback is a specific Parker configuration where the top chord is limited to three slopes (five including the endposts) thus each slope extends over multiple panels.

A Pennsylvania is any configuration of Parker, including Camelback, where the web is complex or subdivided in the manner of a Baltimore truss (connections also occur away from the panel points).

One way to think about it is a Pennsylvania is a Parker that is rigged like a Baltimore truss rather than like a Pratt truss.

Since the rigging defines the Pennsylvania truss, there really isn't anything to debate. There may be a sub variety / call-out specifying a five slope Pennsylvnia as a 'Camelback' Pennsylvania - as far as I know this is not universally regarded as its own sub variety/type.


Art S.

Walnut Street Bridge
Posted July 18, 2020, by Tony Dillon (spansaver [at] hotmail [dot] com)

They look like Pennsylvania trusses to me Calvin. Yes, they do have the 5-slope endpost/upper chord configuration of a Camelback, but the trusses themselves are sub-divided Pennsylvania trusses.

Walnut Street Bridge
Posted December 18, 2014, by Alan Walker (awalker1829 [at] yahoo [dot] com)

This bridge was found unsafe for vehicular traffic and stood abandoned and unused for more than twenty years, despite repeated petitions by the Coast Guard to either repair it or remove it. Community interest in preserving this bridge led the City of Chattanooga to include the restoration of the bridge as a key part of the Tennessee Riverpark. Most folks today do not realize how close we came to losing this bridge.

Walnut Street Bridge
Posted April 5, 2007, by Anonymous

This bridge is a popular spot for college students from UTC as well as Lee University who are looking for a romantic setting for a walk with a date.