Editing Truss bridge

{{short description|Bridge whose load-bearing superstructure is composed of a truss}}
{{distinguish|trestle bridge}}
{{BridgeTypePix|
|type_name        = Truss bridge
|image            = RRTrussBridgeSideView.jpg
|image_title      = A [[truss]] bridge operated by [[Southern Pacific Railroad]] in [[Contra Costa County, California]], converted to pedestrian use and pipeline support
|sibling_names    = None
|descendent_names = [[Cantilever bridge]], [[truss arch bridge]], [[transporter bridge]], [[lattice bridge]]{{Citation needed|reason=Provide reference for descendent bridge types. Who said these bridge types descended from the truss bridge type?|date=May 2010}}
|ancestor_names   = [[Beam bridge]]{{Citation needed|reason=Provide reference which states that the truss bridge type "descended" from the beam bridge.|date=May 2010}}
|carries          = [[Pedestrian]]s, [[Pipeline transport|pipelines]], [[automobile]]s, [[truck]]s, [[light rail]], [[heavy rail]]|span_range=Short to medium – not very long unless it is continuous
|material         = [[Timber]], [[iron]], [[steel]], [[reinforced concrete]], [[prestressed concrete]]
|movable          = May be movable – see [[movable bridge]]
|design           = Medium
|falsework        = Depends upon length, materials, and degree of prefabrication
}}
A '''truss bridge''' is a [[bridge]] whose load-bearing [[superstructure]] is composed of a [[truss]], a structure of connected elements, usually forming triangular units. The connected elements, typically straight, may be stressed from [[tension (mechanics)|tension]], [[compression (physical)|compression]], or sometimes both in response to dynamic loads. There are several types of truss bridges, including some with simple designs that were among the first bridges designed in the 19th and early 20th centuries. A truss bridge is economical to construct primarily because it uses materials efficiently.

== Design ==
[[File:Parts of a truss bridge.svg|thumb|The components of a typical truss bridge<ref>[https://books.google.com/books?id=A3oSAAAAYAAJ Science and Industry] {{Webarchive|url=https://web.archive.org/web/20170215092202/https://books.google.com/books?id=A3oSAAAAYAAJ |date=2017-02-15 }}, Members of a Truss Bridge by Benj. F. La Rue, Home Study Magazine, Published by the Colliery Engineer Company, Vol 3, No. 2, March 1898, pages 67-68.</ref>]]

The nature of a [[truss]] allows the [[analysis]] of its structure using a few assumptions and the application of [[Newton's laws of motion]] according to the branch of [[physics]] known as [[statics]]. For purposes of analysis, trusses are assumed to be [[Pin joint|pin-jointed]] where the straight components meet, meaning that taken alone, every joint on the structure is functionally considered to be a flexible joint as opposed to a rigid joint with the strength to maintain its shape, and the resulting shape and strength of the structure are only maintained by the interlocking of the components. This assumption means that members of the truss (chords, verticals, and diagonals) will act only in tension or compression. A more complex analysis is required where rigid joints impose significant [[bending]] loads upon the elements, as in a [[Vierendeel bridge|Vierendeel truss]].

In the bridge illustrated in the [[infobox]] at the top, vertical members are in tension, lower horizontal members in tension, [[Shear stress|shear]], and bending, outer diagonal and top members are in compression, while the inner diagonals are in tension. The central vertical member stabilizes the upper compression member, preventing it from [[buckling]]. If the top member is sufficiently stiff then this vertical element may be eliminated. If the lower chord (a horizontal member of a truss) is sufficiently resistant to bending and shear, the outer vertical elements may be eliminated, but with additional strength added to other members in compensation. The ability to distribute the forces in various ways has led to a large variety of truss bridge types. Some types may be more advantageous when the wood is employed for compression elements while other types may be easier to erect in particular site conditions, or when the balance between labor, machinery, and material costs has certain favorable proportions.

The inclusion of the elements shown is largely an engineering decision based upon economics, being a balance between the costs of raw materials, off-site fabrication, component transportation, on-site erection, the availability of machinery, and the cost of labor. In other cases, the appearance of the structure may take on greater importance and so influence the design decisions beyond mere matters of economics. Modern materials such as [[prestressed concrete]] and fabrication methods, such as automated [[welding]], and the changing price of steel relative to that of labor have significantly influenced the design of modern bridges.

=== Model bridges ===
A pure truss can be represented as a pin-jointed structure, one where the only forces on the truss members are tension or compression, not bending. This is used in the teaching of statics, by the building of [[spaghetti bridge|model bridges from spaghetti]]. Spaghetti is brittle and although it can carry a modest tension force, it breaks easily if bent. A model spaghetti bridge thus demonstrates the use of a truss structure to produce a usefully strong complete structure from individually weak elements.

==United States==
In the [[United States]], because wood was in abundance, early truss bridges would typically use carefully fitted timbers for members taking compression and iron rods for [[tension member]]s, usually constructed as a [[covered bridge]] to protect the structure. In 1820, a simple form of truss, [[Lattice truss bridge|Town's lattice truss]], was patented, and had the advantage of requiring neither high labor skills nor much metal. Few iron truss bridges were built in the United States before 1850.

Truss bridges became a common type of bridge built from the 1870s through the 1930s. Examples of these bridges still remain across the US, but their numbers are dropping rapidly as they are demolished and replaced with new structures. As metal slowly started to replace timber, [[wrought iron]] bridges in the US started being built on a large scale in the 1870s. Bowstring truss bridges were a common truss design during this time, with their arched top chords. Companies like the [[Massillon Bridge Company]] of [[Massillon, Ohio]], and the [[King Bridge Company]] of [[Cleveland]], became well-known, as they marketed their designs to cities and townships.

The bowstring truss design fell out of favor due to a lack of durability, and gave way to the Pratt truss design, which was stronger. Again, the bridge companies marketed their designs, with the Wrought Iron Bridge Company in the lead. As the 1880s and 1890s progressed, [[steel]] began to replace wrought iron as the preferred material. Other truss designs were used during this time, including the camel-back. By the 1910s, many states developed standard plan truss bridges, including steel Warren [[half-through|pony]] truss bridges.

In the 1920s and 1930s, [[Pennsylvania]] and several states continued to build steel truss bridges, using massive steel through-truss bridges for long spans. Other states, such as [[Michigan]], used standard plan concrete girder and beam bridges, and only a limited number of truss bridges were built.

==Roadbed types==
The truss may carry its [[Deck (bridge)|roadbed]] on top, in the middle, or at the bottom of the truss. Bridges with the roadbed at the top or the bottom are the most common as this allows both the top and bottom to be stiffened, forming a [[box truss]]. When the roadbed is atop the truss, it is a deck truss; an example of this was the [[I-35W Mississippi River bridge]]. When the truss members are both above and below the roadbed it is called a through truss; an example of this is the [[Pulaski Skyway]], and where the sides extend above the roadbed but are not connected, a pony truss or [[half-through]] truss.

Sometimes both the upper and lower chords support roadbeds, forming a [[Double-deck bridge|double-decked truss]]. This can be used to separate rail from road traffic or to separate the two directions of road traffic.

Since through truss bridges have supports located over the bridge deck, they are susceptible to being hit by [[oversize load|overheight loads]] when used on highways. The [[I-5 Skagit River bridge collapse]]d after such a strike; before the collapse, similar incidents had been common and had necessitated frequent repairs.<ref name="King5 20130526">{{cite web |title=Temporary Skagit River bridge may be open in weeks |date=May 26, 2013 |work=King 5 television |url=http://www.king5.com/news/NTSB-Skagit-River-bridge-had-history-of-hits-209001771.html |access-date=March 27, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130607221909/http://www.king5.com/news/NTSB-Skagit-River-bridge-had-history-of-hits-209001771.html |archive-date=June 7, 2013 }}</ref>

===Gallery===
<gallery widths="150px" class="center">
Image:LittleManateeRiver.jpg|Pratt '''through truss''' of the former [[Seaboard Air Line Railway]], located near [[Willow, Florida]]; abandoned since the mid-1980s
Image:ErieCanalRRBridge04 1A.jpg|'''Deck truss''' railroad bridge over the [[Erie Canal]] in [[Lockport (city), New York|Lockport, New York]]
Image:General Hertzog Bridge over Orange River at Aliwal North.jpg|The four span through truss [[James Barry Munnik Hertzog|General Hertzog Bridge]] over the [[Orange River]] at [[Aliwal North]] carries vehicular traffic
File:05-23-13 Skagit Bridge Collapse.jpg|The through truss Skagit River bridge on Interstate 5 [[I-5 Skagit River Bridge collapse|collapsed]] after an overhead support was hit by a passing truck
File:Old San Jacinto River Truss Bridge -- Humble, Texas.jpg|Old [[San Jacinto River (Texas)|San Jacinto River]] truss bridge in [[Humble, Texas]]
Image:Puente Tacuarembó 02.jpg|'''Pony truss''' bridge of reinforced concrete
Image:Sky gate bridge01s3200.jpg|Sky Gate Bridge R at [[Kansai International Airport]], [[Osaka]], Japan, is the longest double-decked truss bridge in the world. It carries three lanes of automobile traffic on top and two of rail below over nine truss spans.
File:Railroad Truss bridge over trinity river near Goodrich, Texas.jpg|Railroad Truss bridge over Trinity River near [[Goodrich, Texas]]
Image:HartBridgeJax.jpg|The [[Hart Bridge]] spanning the [[St. Johns River]] in [[Jacksonville, Florida]], is a continuous, cantilevered truss bridge which combines a suspended road deck on the {{convert|1088|ft|order=flip|adj=on}} main span and through truss decks on the adjacent approach spans
File:Columbus and Greenville Railway bridge over Yazoo River.jpg|A [[railway bridge]] with a [[Track (rail transport)|rail track]] in [[Leflore County, Mississippi]]
File:Chevelon Creek Bridge.jpg|Chevelon Creek Warren Pony Truss Bridge,Chevelon Creek, Navajo County Arizona built 1913
File:Željeznički most, Mursko Središće.3.jpg|Side view of the iron truss railway bridge over [[Mura (Drava)|Mura River]] in [[Mursko Središće]], [[Croatia]]
File:Railroad Truss Drawbridge across Buffalo Bayou -- Houston.jpg|Railroad Truss Drawbridge across Buffalo Bayou—Houston
<!-- Image:Hampden bridge-wagga.jpg|Hampden Bridge showing the Allan truss design -->
</gallery>

==Multiple spans==
Truss bridges consisting of more than one [[Span (engineering)|span]] may be either a [[Continuous truss bridge|continuous truss]] or a series of simple trusses. In the simple truss design, each span is supported only at the ends and is fully independent of any adjacent spans. Each span must fully support the weight of any vehicles traveling over it (the [[Structural load#Live load|live load]]).

In contrast, a continuous truss functions as a single rigid structure over multiple supports. This means that the live load on one span is partially supported by the other spans, and consequently it is possible to use less material in the truss.<ref name=adams1909>{{cite book |editor1-last=Adams |editor1-first=Charles Kendall |title=Universal Cyclopædia and Atlas |date=1909 |publisher=D. Appleton and Company |location=New York |pages=161–174 |url=https://books.google.com/books?id=TttTAAAAYAAJ |access-date=September 1, 2022 |language=en |chapter=Bridges}}</ref>{{rp|168}} Continuous truss bridges were not very common before the mid-20th century because they are [[statically indeterminate]], which makes them difficult to design without the [[Computer-aided engineering|use of computers]].

A multi-span truss bridge may also be constructed using [[Cantilever bridge|cantilever]] spans, which are supported at only one end rather than both ends like other types of trusses. Unlike a continuous truss, a cantilever truss does not need to be connected rigidly, or indeed at all, at the center.<ref name=adams1909/>{{rp|169–170}} Many cantilever bridges, like the [[Quebec Bridge]] shown below, have two cantilever spans supporting a simple truss in the center. The bridge would remain standing if the simple truss section were removed.

<gallery widths="150px" class="center">
File:Bally Bridge.jpg|A multi-span '''simple truss''' bridge, [[Vivekananda Setu]] over the [[Hooghly River]] in [[Kolkata]], India
File:Kingston-Rhinecliff Bridge2.JPG|A '''continuous truss''' bridge, [[Kingston–Rhinecliff Bridge]] over the [[Hudson River]] in [[New York (state)|New York]], United States
File:Le pont de Québec, de l'embouchure de la rivière Chaudière.jpg|A '''cantilever truss''' bridge, [[Quebec Bridge]] over the [[Saint Lawrence River]] in [[Quebec]], Canada
</gallery>

==Truss types used in bridges==

{{Split section|date=February 2023}}

Bridges are the most widely known examples of truss use. There are many types,<ref>{{cite book|last=Kirsanov|first=M.|year=2019|title=Planar Trusses: Schemes and Formulas|publisher=Cambridge Scholars Publishing|location=GB|isbn=978-1-5275-3531-2|page=206}}</ref> some of them dating back hundreds of years. Below are some of the more common designs.

=== Allan truss ===
[[Image:Hampden Bridge Wagga design.jpg|thumb|An Allan truss]]
The '''Allan truss''', designed by [[Percy Allan]], is partly based on the [[Howe truss]]. The first Allan truss was completed on 13 August 1894 over Glennies Creek at Camberwell, New South Wales and the last Allan truss bridge was built over Mill Creek near [[Wisemans Ferry, New South Wales|Wisemans Ferry]] in 1929.<ref>{{cite web|title=Timber Truss Bridges|url=http://www.rta.nsw.gov.au/environment/downloads/heritage/bridge-types_historical-overviews_2006-timbertruss.pdf|work=McMillan Britton & Kell Pty Limited|publisher=Roads and Traffic Authority|access-date=23 November 2010|date=December 1998|archive-date=19 March 2011|archive-url=https://web.archive.org/web/20110319232920/http://www.rta.nsw.gov.au/environment/downloads/heritage/bridge-types_historical-overviews_2006-timbertruss.pdf|url-status=live}}</ref><ref>{{cite web|title=Tharwa Bridge Conservation Management Plan|url=http://www.cmd.act.gov.au/__data/assets/pdf_file/0009/148509/Tharwa_Bridge_CMP_reduced.pdf|work=Philip Leeson Architects|publisher=Roads ACT|access-date=23 November 2010|pages=42, 45|date=5 March 2009|archive-date=21 February 2011|archive-url=https://web.archive.org/web/20110221182535/http://www.cmd.act.gov.au/__data/assets/pdf_file/0009/148509/Tharwa_Bridge_CMP_reduced.pdf|url-status=live}}</ref> Completed in March 1895, the [[Tharwa Bridge]] located at [[Tharwa, Australian Capital Territory]], was the second Allan truss bridge to be built, the oldest surviving bridge in the [[Australian Capital Territory]] and the oldest, longest continuously used Allan truss bridge.<ref>{{cite web|title=1307.8 – Australian Capital Territory in Focus, 2007|url=http://www.abs.gov.au/ausstats/abs@.nsf/Products/80BD523C6BA53B02CA2573A1007B2DA5?opendocument|work=[[Australian Bureau of Statistics]]|access-date=23 November 2010|date=27 November 2007|archive-date=14 October 2012|archive-url=https://web.archive.org/web/20121014225551/http://www.abs.gov.au/ausstats/abs@.nsf/Products/80BD523C6BA53B02CA2573A1007B2DA5?opendocument|url-status=live}}</ref><ref>{{cite web|title=Tharwa Bridge|url=http://www.engineer.org.au/tharwa_bridge.html|url-status=dead|archive-url=https://web.archive.org/web/20110219064151/http://www.engineer.org.au/tharwa_bridge.html|archive-date=2011-02-19|access-date=23 November 2010|work=[[Engineers Australia]]|publisher=Canberra's Engineering Heritage}}</ref><ref>{{Cite web|title=July 2010 Newsletter {{!}} Engineers Australia|url=https://www.engineersaustralia.org.au/resource-centre/resource/july-2010-newsletter-0|access-date=2021-03-24|website=www.engineersaustralia.org.au|archive-date=2021-10-01|archive-url=https://web.archive.org/web/20211001045013/https://www.engineersaustralia.org.au/resource-centre/resource/july-2010-newsletter-0|url-status=live}}</ref> Completed in November 1895, the [[Hampden Bridge (Wagga Wagga)|Hampden Bridge]] in [[Wagga Wagga, New South Wales]], Australia, the first of the Allan truss bridges with overhead bracing, was originally designed as a steel bridge but was constructed with timber to reduce cost.<ref>{{cite web|title=Minutes of State Heritage Register Committee meeting|url=http://www.heritage.nsw.gov.au/docs/heritagecouncil/shrNovember_2008.pdf|archive-url=https://web.archive.org/web/20110317131142/http://www.heritage.nsw.gov.au/docs/heritagecouncil/shrNovember_2008.pdf|url-status=dead|archive-date=17 March 2011|work=State Heritage Register Committee|publisher=Heritage Council of New South Wales|access-date=23 November 2010|page=5|date=5 November 2008}}</ref> In his design, Allan used Australian [[ironbark]] for its strength.<ref>{{cite web | title = Hampden Bridge, Wagga Wagga, NSW | publisher = Timber Building in Australia | url = http://oak.arch.utas.edu.au/projects/view_projectinfo.asp?projID=21 | access-date = 2008-06-05 | url-status = dead | archive-url = https://web.archive.org/web/20130512053920/http://oak.arch.utas.edu.au/projects/view_projectinfo.asp?projID=21 | archive-date = 2013-05-12 }}</ref> A similar bridge also designed by Percy Allen is the [[Victoria Bridge, Picton|Victoria Bridge]] on Prince Street, [[Picton, New South Wales]]. Also constructed of ironbark, the bridge is still in use today for pedestrian and light traffic.<ref>Google-maps "-34.180255,150.610654" clearly shows bridge with traffic</ref>

=== Bailey truss ===
[[File:Bailey-truss.svg|thumb]]
[[Image:PontBailey.jpg|thumb|Bailey truss over the [[Meurthe River]] in France]]
{{Main|Bailey bridge}}
The '''Bailey truss''' was designed by the British in 1940–1941 for military uses during World War II. A short selection of prefabricated modular components could be easily and speedily combined on land in various configurations to adapt to the needs at the site and allow rapid deployment of completed trusses. In the image, note the use of pairs of doubled trusses to adapt to the span and load requirements. In other applications the trusses may be stacked vertically, and doubled as necessary.

=== Baltimore truss ===
[[File:Baltimore-truss.svg|thumb]]
The '''Baltimore truss''' is a subclass of the Pratt truss. A Baltimore truss has additional bracing in the lower section of the truss to prevent buckling in the compression members and to control deflection. It is mainly used for rail bridges, showing off a simple and very strong design. In the Pratt truss the intersection of the verticals and the lower horizontal tension members are used to anchor the supports for the short-span girders under the tracks (among other things). With the Baltimore truss, there are almost twice as many points for this to happen because the short verticals will also be used to anchor the supports. Thus the short-span girders can be made lighter because their span is shorter. A good example of the Baltimore truss is the [[Amtrak Old Saybrook – Old Lyme Bridge]] in [[Connecticut]], United States.

=== Bollman truss ===
{{Main|Bollman Truss Railroad Bridge}}
[[Image:Bollman-bridge-1.jpg|thumb|A Bollman truss in [[Savage, Maryland]]; built in 1869, it was moved to Savage in 1887 and has been in continuous use since as a pedestrian bridge.

{{Coord|39|8|5.42|N|76|49|30.33|W}}]]
The '''Bollman Truss Railroad Bridge''' at [[Savage, Maryland]], United States is the only surviving example of a revolutionary design in the history of American bridge engineering. The type was named after its inventor, [[Wendel Bollman]], a self-educated [[Baltimore, Maryland|Baltimore]] engineer. It was the first successful all-metal bridge design (patented in 1852) to be adopted and consistently used on a railroad. The design employs [[wrought iron]] tension members and [[cast iron]] compression members. The use of multiple independent tension elements reduces the likelihood of catastrophic failure. The structure was also easy to assemble.

[[Wells Creek Bollman Bridge]] is the only other bridge designed by Wendel Bollman still in existence, but it is a Warren truss configuration.

=== Bowstring truss ===
[[File:Bowstring-truss.svg|thumb|Bowstring truss]]
[[Image:Blackfriars Street Bridge from south riverbed, fall 2007.jpg|thumb|A bowstring truss bridge, in [[London, Ontario]], Canada]]
The '''bowstring truss''' bridge was patented in 1841<ref>{{US patent|2064}}</ref> by [[Squire Whipple]].<ref name="Gardner">{{cite book|last=Gardner|first=Denis P.|year=2008|title=Wood, Concrete, Stone, Steel: Minnesota's Historic Bridges|publisher=University of Minnesota Press|location=Minneapolis|isbn=978-0-8166-4666-1|page=51}}</ref> While similar in appearance to a [[tied-arch bridge]], a bowstring truss has diagonal load-bearing members: these diagonals result in a structure that more closely matches a [[Truss bridge#Warren truss|Parker truss]] or [[Pratt truss]] than a [[true arch]].

===Brown truss===
{{Main|Brown truss}}
[[Image:BrownTrussDiagram.svg|thumb|Brown truss]]
In the '''Brown truss''' all vertical elements are under tension, with exception of the end posts. This type of truss is particularly suited for timber structures that use iron rods as tension members.

===Brunel truss===
See [[#Lenticular truss|Lenticular truss]] below.

===Burr arch truss===
{{Main|Burr Arch Truss}}
[[Image:Baumgardener's Covered Bridge Inside Center 3008px.jpg|thumb|[[Baumgardener's Covered Bridge]], a [[Burr Arch Truss]] in [[Lancaster County, Pennsylvania]]]]

This combines an arch with a truss to form a structure both strong and rigid.

=== Cantilever truss ===
{{Main|Cantilever bridge}}
[[File:Bb-forthrailbridge.jpg|thumb|[[Forth Bridge]], crossing the [[Firth of Forth]] in eastern Scotland]]
Most trusses have the lower chord under tension and the upper chord under compression. In a '''cantilever truss''' the situation is reversed, at least over a portion of the span. The typical cantilever truss bridge is a "balanced cantilever", which enables the construction to proceed outward from a central vertical spar in each direction. Usually these are built in pairs until the outer sections may be anchored to footings. A central gap, if present, can then be filled by lifting a conventional truss into place or by building it in place using a "traveling support". In another method of construction, one outboard half of each balanced truss is built upon temporary falsework. When the outboard halves are completed and anchored the inboard halves may then be constructed and the center section completed as described above.

=== Fink truss ===
{{Main|Fink truss}}
[[Image:Bridges 20.png|thumb|A [[Fink truss]] (half span and cross section)]]
The '''Fink truss''' was designed by [[Albert Fink]] of Germany in 1854. This type of bridge was popular with the [[Baltimore and Ohio Railroad]]. The [[High Bridge (Appomattox River)|Appomattox High Bridge]] on the [[Norfolk and Western Railway]] included 21 Fink deck truss spans from 1869 until their replacement in 1886.

{{anchor|Inverted Fink truss}}
There are also '''inverted Fink truss''' bridges such as the [[Moody Pedestrian Bridge]] in Austin, Texas.

===Howe truss===
{{main|Howe truss}}
[[Image:Howe truss.PNG|thumb|A [[Howe truss]] with diagonals under compression under balanced loading]]
The '''Howe truss''', patented in 1840 by [[Massachusetts]] [[millwright]] [[William Howe (architect)|William Howe]], includes vertical members and diagonals that slope up towards the center, the opposite of the [[Pratt truss]].<ref name=Matsuo>Matsuo Bridge Company, [http://www.matsuo-bridge.co.jp/english/bridges/basics/truss.shtm Bridge Types – Truss] {{webarchive|url=https://web.archive.org/web/20060905130514/http://matsuo-bridge.co.jp/english/bridges/basics/truss.shtm |date=2006-09-05 }}, accessed September 2007</ref>
In contrast to the Pratt truss, the diagonal web members are in compression and the vertical web members are in tension. Few of these bridges remain standing. Examples include [[Jay Bridge]] in [[Jay, New York]]; [[McConnell's Mill Covered Bridge]] in [[Slippery Rock Township, Lawrence County, Pennsylvania]]; [[Sandy Creek Covered Bridge State Historic Site|Sandy Creek Covered Bridge]] in [[Jefferson County, Missouri]]; and [[Westham Island Bridge]] in [[Delta, British Columbia]], Canada.
<gallery class="center">
Image:Large Timber Howe Truss.jpg|A large timber Howe truss in a commercial building.
Image:Jay Bridge interior.jpg|[[Jay Bridge]] showing the truss design.
Image:Westham island bridge.jpg|[[Westham Island Bridge]] showing its wooden truss design.
</gallery>

=== K-truss ===
[[Image:K-Truss.svg|thumb|K-truss]]
[[Image:2016-08-12_18_32_52_View_north_along_Interstate_895_%28Baltimore_Harbor_Tunnel_Thruway%29_as_it_crosses_over_the_CSX%27s_Curtis_Bay_Branch_rail_line_in_Baltimore_City%2C_Maryland.jpg|thumb|The [[Interstate 895 in Maryland|I-895]] K-truss in [[Baltimore]]]]
The '''K-truss''' is named after the ''K'' formed in each panel by the vertical member and two oblique members. Examples include the Südbrücke rail bridge over the River Rhine, Mainz, Germany,<ref>[https://web.archive.org/web/20160304114630/https://ssl.panoramio.com/photo/48902816 Panoramio]- Reviewed 2020-03-23</ref> the bridge on I-895 (Baltimore Harbor Tunnel Thruway) in Baltimore, Maryland, the [[Long–Allen Bridge (Morgan City)|Long–Allen Bridge]] in [[Morgan City, Louisiana]] (Morgan City Bridge) with three 600-foot-long spans, and the Wax Lake Outlet bridge in [[St. Mary Parish, Louisiana|Calumet, Louisiana]]<ref>[http://wwwsp.dotd.la.gov/Inside_LaDOTD/Divisions/Engineering/HBI/Documents1/Historic_Context_For_Louisiana_Bridges.pdf ''Historic Context for Louisiana Bridges''] {{Webarchive|url=https://web.archive.org/web/20201224200205/http://wwwsp.dotd.la.gov/Inside_LaDOTD/Divisions/Engineering/HBI/Documents1/Historic_Context_For_Louisiana_Bridges.pdf |date=2020-12-24 }}- Retrieved 2020-03-23 (section 3, pp 71)</ref>

=== Kingpost truss ===
{{Main|King post}}
[[Image:king post truss.png|thumb|King&nbsp;post&nbsp;truss]]
One of the simplest truss styles to implement, the '''king post''' consists of two angled supports leaning into a common vertical support.

=== Lattice truss (Town's lattice truss) ===
[[File:Lattice-truss.svg|thumb|Lattice, or Warren quadrangular truss illustrated]]
[[File:Runcorn Railway Bridge.jpg|thumb|[[Runcorn Railway Bridge]], a lattice truss]]
{{Main|Lattice truss bridge}}
This type of bridge uses a substantial number of lightweight elements, easing the task of construction. Truss elements are usually of wood, iron, or steel.

=== Lenticular truss ===
[[File:Lenticular-truss.svg|thumb]]
[[File:Joseph R. Oulette Bridge (Aiken Street Bridge) from east in 2010.jpg|thumb|Aiken Street Bridge in [[Lowell, Massachusetts]], built in 1883 by [[Berlin Iron Bridge Co.]], is the longest lenticular truss bridge in the United States with five spans, and the second-oldest lenticular truss bridge in [[Massachusetts]].<ref name="Aiken">{{cite web |title=Aiken Street Bridge: Ouellette Bridge |url=http://historicbridges.org/bridges/browser/?bridgebrowser=massachusetts/aiken/ |website=HistoricBridges.org |access-date=9 July 2018 |language=en |date=2018 |archive-date=9 July 2018 |archive-url=https://web.archive.org/web/20180709215738/http://historicbridges.org/bridges/browser/?bridgebrowser=massachusetts%2Faiken%2F |url-status=live }}</ref>]]
[[Image:Royal albert bridge hist.jpg|thumb|[[Royal Albert Bridge]] under construction in 1859]]
A '''lenticular truss''' bridge includes a lens-shape truss, with trusses between an upper chord functioning as an arch that curves up and then down to end points, and a lower chord (functioning as a suspension cable) that curves down and then up to meet at the same end points.<ref name=Boothby >{{cite web |last=Boothby |first=Thomas |year=2020 |title=Designing American Lenticular Truss Bridges 1878–1900 |publisher=History Cooperative |url=https://historycooperative.org/journal/designing-american-lenticular-truss-bridges-1878-1900/ |access-date=5 March 2020 |archive-date=5 November 2020 |archive-url=https://web.archive.org/web/20201105231708/https://historycooperative.org/journal/designing-american-lenticular-truss-bridges-1878-1900/ |url-status=live }}</ref> Where the arches extend above and below the roadbed, it is called a '''lenticular pony truss bridge'''. The '''Pauli truss''' bridge is a specific variant of the lenticular truss, but the terms are not interchangeable.<ref name=Boothby />

One type of lenticular truss consists of arcuate upper compression chords and lower [[eyebar]] chain tension links. [[Isambard Kingdom Brunel|Brunel]]'s [[Royal Albert Bridge]] over the [[River Tamar]] between [[Devon]] and [[Cornwall]] uses a single tubular upper chord. As the horizontal tension and compression forces are balanced these horizontal forces are not transferred to the supporting pylons (as is the case with most arch types). This in turn enables the truss to be fabricated on the ground and then to be raised by jacking as supporting masonry pylons are constructed. This truss has been used in the construction of a stadium,<ref>{{Cite web |url=http://www.azcardinals.com/stadium/detail.php?PRKey=492 |title=Arizona Cardinals Stadium |access-date=2008-04-28 |archive-url=https://web.archive.org/web/20071103031815/http://www.azcardinals.com/stadium/detail.php?PRKey=492 |archive-date=2007-11-03 |url-status=dead }}</ref> with the upper chords of parallel trusses supporting a roof that may be rolled back. The [[Smithfield Street Bridge]] in [[Pittsburgh, Pennsylvania]], is another example of this type.

[[File:Munich Grosshesseloher-Bruecke.jpeg|thumb|The old Großhesselohe bridge before 1905, designed by Friedrich von Pauli]]
An example of a lenticular pony truss bridge that uses regular spans of iron is the [[Turn-of-River Bridge]] designed and manufactured by the [[Berlin Iron Bridge Co.]]

The Pauli truss is a variant of the lenticular truss, "with the top chord carefully shaped so that it has a constant force along the entire length of the truss."<ref name=Boothby /> It is named after {{ill|Friedrich Augustus von Pauli|de}}, whose 1857 railway bridge (the {{ill|Großhesseloher Brücke|de|Großhesselohe}}) spanned the [[Isar]] near [[Munich]]. (''See also [[Grosshesselohe Isartal station]]''.) The term Pauli truss is not interchangeable with the term lenticular truss and, according to Thomas Boothby, the casual use of the term has clouded the literature.<ref name=Boothby />

=== Long truss ===
[[File:Long Truss Bushing CB (Versailles SP) 00003r.jpg|thumb|[[Heritage Documentation Programs#Historic American Engineering Record|HAER]] diagram of a Long truss]]
The '''Long truss''' was designed by Stephen H. Long in 1830. The design resembles a [[#Howe truss|Howe truss]], but is entirely made of wood instead of a combination of wood and metal.<ref>{{Cite web |url=http://www.coveredbridgesite.com/ny/truss.html#Long |title=CoveredBridgeSite, Long truss |access-date=2008-10-20 |archive-date=2018-05-02 |archive-url=https://web.archive.org/web/20180502025046/http://www.coveredbridgesite.com/ny/truss.html#Long |url-status=live }}</ref> The longest surviving example is the [[Eldean Covered Bridge]] north of [[Troy, Ohio]], spanning {{convert|224|ft|m}}.<ref>[http://www.waymarking.com/waymarks/WM40GG_Eldean_Covered_Bridge_Troy_Ohio Eldean Covered Bridge – Troy, Ohio – Covered Bridges on] {{Webarchive|url=https://web.archive.org/web/20121018192806/http://www.waymarking.com/waymarks/WM40GG_Eldean_Covered_Bridge_Troy_Ohio |date=2012-10-18 }}. Waymarking.com. Retrieved on 2013-07-23.</ref> One of the earliest examples is the [[Old Blenheim Bridge]], which with a span of {{convert|210|ft|m}} and a total length of {{convert|232|ft|m}} long was the second-longest covered bridge in the United States, until its destruction from flooding in 2011.

The Busching bridge, often erroneously used as an example of a Long truss, is an example of a Howe truss, as the verticals are metal rods.<ref>{{cite web |url=http://www.clrconstruction.com/buschingbridge.htm |title=Busching Bridge |publisher=CLR Inc. Construction and Transportation |access-date=June 25, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20110820203434/http://www.clrconstruction.com/buschingbridge.htm |archive-date=August 20, 2011 }}</ref>

=== Parker (camelback) truss ===
{{Redirect|Camelback bridge|the concrete bridge type|concrete curved-chord through girder bridge}}
[[File:Parker-truss.svg|thumb]]
[[Image:Woolsey Bridge oblique view.jpg|thumb|[[Woolsey Bridge]], a Parker camelback truss]]
A '''Parker truss''' bridge is a Pratt truss design with a polygonal upper chord. A "camelback" is a subset of the Parker type, where the upper chord consists of exactly five segments. An example of a Parker truss is the [[Traffic Bridge (Saskatoon)|Traffic Bridge]] in [[Saskatoon]], Canada. An example of a camelback truss is the [[Woolsey Bridge]] near [[Woolsey, Arkansas]].

=== Partridge truss ===
[[File:Partridge Truss.png|thumb|Partridge truss design]]
Designed and patented in 1872 by [[Reuben Partridge]], after local bridge designs proved ineffective against road traffic and heavy rains.<ref name=Kennedy>Kennedy, Willella Shearer. "Heritage: Being Little Stories of Union County". ''Union County Historical Society'', Printed by The Marysville Journal Tribune. 1963. Pg. 48.</ref> It became the standard for [[covered bridge]]s built in central Ohio in the late 1800s and early 1900s.

=== Pegram truss ===
[[Image:Pegram.svg|thumb|Pegram&nbsp;truss]]
The '''Pegram truss''' is a hybrid between the Warren and Parker trusses where the upper chords are all of equal length and the lower chords are longer than the corresponding upper chord. Because of the difference in upper and lower chord length, each panel is not square. The members which would be vertical in a Parker truss vary from near vertical in the center of the span to diagonal near each end, similar to a Warren truss. [[George H. Pegram]], while the chief engineer of Edge Moor Iron Company in [[Wilmington, Delaware]], patented this truss design in 1885.<ref>{{Cite patent | inventor-last = Pegram| inventor-first =George H.| publication-date = 10-24-1881| issue-date = 03-24-1885 | title = Truss for Roofs and Bridges| country-code = US | description = | patent-number = 314262 | postscript = <!--None-->}}</ref>

The Pegram truss consists of a Parker type design with the vertical posts leaning towards the center at an angle between 60 and 75°. The variable post angle and constant chord length allowed steel in existing bridges to be recycled into a new span using the Pegram truss design. This design also facilitated reassembly and permitted a bridge to be adjusted to fit different span lengths. There are twelve known remaining Pegram span bridges in the United States with seven in [[Idaho]], two in [[Kansas]], and one each in [[California]], [[Washington (state)|Washington]], and [[Utah]].{{citation needed|date=February 2013}}

{{anchor|Pennsylvania through truss}}

=== Pennsylvania (Petit) truss ===
[[File:Pennsylvania-truss.svg|thumb]]
[[File:Fair Oaks Bridge.jpg|thumb|The [[Fair Oaks Bridge]] is an example of Pennsylvania Petit truss bridge.]]
The '''Pennsylvania (Petit) truss''' is a variation on the [[#Pratt truss|Pratt truss]].<ref>{{Cite web |title=NCDOT: Truss Bridges |url=https://www.ncdot.gov/initiatives-policies/Transportation/bridges/historic-bridges/bridge-types/Pages/truss.aspx |access-date=2024-10-28 |website=NCDOT |language=en-US}}</ref> The Pratt truss includes braced diagonal members in all panels; the Pennsylvania truss adds to this design half-length struts or ties in the top, bottom, or both parts of the panels. It is named after the [[Pennsylvania Railroad]], which pioneered this design. It was once used for hundreds of bridges in the United States, but fell out of favor in the 1930s and very few examples of this design remain.<ref>[http://ohp.parks.ca.gov/pages/1067/files/healdburg%20bridge%20nr%20nomination.pdf National Register of Historic Places Registration Form] {{Webarchive|url=https://web.archive.org/web/20130115220840/http://www.ohp.parks.ca.gov/pages/1067/files/healdburg%20bridge%20nr%20nomination.pdf |date=2013-01-15 }} for [[Healdsburg Memorial Bridge]], California State Park System, accessed 2011-12-26.</ref> Examples of this truss type include the [[Lower Trenton Bridge]] in [[Trenton, New Jersey]], the [[Fort Wayne Street Bridge]] in [[Goshen, Indiana]], the [[Schell Bridge]] in [[Northfield, Massachusetts]], the [[Inclined Plane Bridge]] in [[Johnstown, Pennsylvania]], the [[Easton–Phillipsburg Toll Bridge]] in [[Easton, Pennsylvania]], the [[Connecticut River Bridge]] in [[Brattleboro, Vermont]], the [[Metropolis Bridge]] in [[Metropolis, Illinois]], and the [[Healdsburg Memorial Bridge]] in [[Healdsburg, California]].

=== Post truss ===
[[Image:Post truss.svg|thumb|right|A Post truss]]
A '''Post truss''' is a hybrid between a Warren truss and a double-intersection Pratt truss. Invented in 1863 by Simeon S. Post, it is occasionally referred to as a ''Post patent truss'' although he never received a patent for it.<ref>{{cite book
 | last = Jackson
 | first = Donald C.
 | title = Great American Bridges and Dams
 | year = 1995
 | publisher = John Wiley & Sons
 | location = New York
 | isbn = 978-0-471-14385-7
 | page = [https://archive.org/details/greatamericanbri0000jack/page/92 92]
 | url = https://archive.org/details/greatamericanbri0000jack/page/92
 }}</ref> The [[Ponakin Bridge]] and the [[Bell Ford Bridge]] are two examples of this truss.

=== Pratt truss ===
[[Image:Pratt truss.svg|thumb|A Pratt truss]]
[[File:Gatton Railway Bridge.JPG|thumb|Gatton Railway Bridge showing the Pratt truss design]]
[[File:Macleay River Railway Bridge Kempsey NSW.jpg|thumb|[[Macleay River railway bridge, Kempsey|Macleay River Railway Bridge]], a Pratt truss design at Kempsey in NSW, Australia]]
A '''Pratt truss''' includes vertical members and diagonals that slope down towards the center, the opposite of the [[#Howe truss|Howe truss]].<ref name="Matsuo"/> The interior diagonals are under tension under balanced loading and vertical elements under compression. If pure tension elements (such as [[eyebar]]s) are used in the diagonals, then crossing elements may be needed near the center to accept concentrated live loads as they traverse the span. It can be subdivided, creating Y- and K-shaped patterns. The Pratt truss was invented in 1844 by [[Thomas Willis Pratt|Thomas]] and Caleb Pratt.<ref>Thomas and Caleb Pratt, [https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=3523A&KC=A US patent 3523] in European Patent Office database</ref><ref name=MHT/> This truss is practical for use with spans up to {{convert|250|ft|m}} and was a common configuration for railroad bridges as truss bridges moved from wood to metal. They are [[Statically indeterminate|statically determinate]] bridges, which lend themselves well to long spans. They were common in the United States between 1844 and the early 20th century.<ref name=MHT/>

Examples of Pratt truss bridges are the [[Governor's Bridge (Bowie, Maryland)|Governor's Bridge]] in [[Maryland]];<ref name=MHT>{{citation|title=Maryland Historical Trust Property Number PG-74B-1 & AA-85I|series=Maryland Inventory of Historic Bridges|url=http://msa.maryland.gov/megafile/msa/stagsere/se1/se5/018000/018900/018913/pdf/msa_se5_18913.pdf|access-date=5 January 2013|archive-date=26 December 2013|archive-url=https://web.archive.org/web/20131226080353/http://msa.maryland.gov/megafile/msa/stagsere/se1/se5/018000/018900/018913/pdf/msa_se5_18913.pdf|url-status=live}}</ref> the [[Hayden Bridge (Springfield, Oregon)|Hayden RR Bridge]] in [[Springfield, Oregon]], built in 1882; the [[Dearborn River High Bridge]] near Augusta, Montana, built in 1897; and the [[Fair Oaks Bridge]] in [[Fair Oaks, California]], built 1907–09.

The [[Scenic Bridge]] near [[Tarkio, Montana]], is an example of a Pratt deck truss bridge, where the roadway is on top of the truss.

===Queenpost truss===
{{Main|Queen post}}
[[Image:queen post truss.png|thumb|A [[Queen post]] truss]]
The '''queenpost truss''', sometimes called "queen post" or queenspost, is similar to a king post truss in that the outer supports are angled towards the center of the structure. The primary difference is the horizontal extension at the center which relies on [[Beam (structure)|beam]] action to provide mechanical stability. This truss style is only suitable for relatively short spans.<ref>[http://www.dot.state.oh.us/se/coveredbridges/truss_types.htm Covered Bridge's Truss Types<!-- Bot generated title -->] {{webarchive|url=https://web.archive.org/web/20060904102208/http://www.dot.state.oh.us/se/coveredbridges/truss_types.htm |date=2006-09-04 }}</ref>

===Smith truss===
[[File:Smith truss.jpg|thumb|Smith truss]]
The '''Smith truss''', patented by Robert W Smith on July 16, 1867,<ref name="smithpatent">{{cite web |title=R.W. Smith Truss Patent 66,900 |url=http://pdfpiw.uspto.gov/.piw?PageNum=0&docid=00066900&IDKey=AB12EEE16910&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetahtml%2FPTO%2Fpatimg.htm |website=United States Patent Office |publisher=United States of America |access-date=10 November 2018 |date=July 16, 1867 |archive-date=11 November 2018 |archive-url=https://web.archive.org/web/20181111000125/http://pdfpiw.uspto.gov/.piw?PageNum=0&docid=00066900&IDKey=AB12EEE16910&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetahtml%2FPTO%2Fpatimg.htm |url-status=live }}</ref> has mostly diagonal criss-crossed supports. Smith's company used many variations of this pattern in the wooden covered bridges it built.

While most all of the bridges built in the 19th century in the [[Jackson County, Ohio]], area used the Smith truss design, the [[Johnson Road Covered Bridge]] is the last known surviving example in the state.<ref name=OHPD>{{cite book |url=https://books.google.com/books?id=YfvhVln0D20C&pg=GBS.PA419.w.1.2.0.1 |title=Ohio Historic Places Dictionary, Volume 2 |date=1999 |publisher=Somerset Publishers, Inc. |editor=Lorrie K. Owen |page=794 |isbn=9781878592705 |access-date=2020-01-05 |archive-date=2020-06-14 |archive-url=https://web.archive.org/web/20200614043333/https://books.google.com/books?id=YfvhVln0D20C&pg=GBS.PA419.w.1.2.0.1 |url-status=live }}</ref>

===Thacher truss===
[[File:Thacher-truss.svg|thumb|A Thacher truss bridge]]
The '''Thacher truss''' <ref>{{Cite web|url=https://www.loc.gov/item/va1284/|title=Thacher Truss Bridge, Spanning Linville Creek, Broadway, Rockingham County, VA|website=[[Library of Congress]]|access-date=2021-02-04|archive-date=2020-12-13|archive-url=https://web.archive.org/web/20201213145340/https://www.loc.gov/item/va1284/|url-status=live}}</ref> combines some of the characteristics of a [[#Pratt truss|Pratt truss]] with diagonals under tension and of a [[#Howe truss|Howe truss]] with diagonals under compression, which is rare.

=== Truss arch ===
{{Main|Truss arch bridge}}
[[File:Truss Bridge pg 382.jpg|thumb|Truss arch bridge]]
A '''truss arch''' may contain all horizontal forces within the arch itself, or alternatively may be either a thrust arch consisting of a truss, or of two arcuate sections pinned at the apex. The latter form is common when the bridge is constructed as [[cantilever]] segments from each side as in the [[Navajo Bridge]].

===Vierendeel truss===
{{Main|Vierendeel bridge}}
[[Image:Grammene-vierendeelbridge 20030618.jpg|thumb|A [[Vierendeel bridge]]]]
The '''Vierendeel truss''', unlike common pin-jointed trusses, imposes significant bending forces upon its members—but this in turn allows the elimination of many diagonal elements. It is a structure where the members are not triangulated but form rectangular openings, and is a frame with fixed joints that are capable of transferring and resisting bending moments. While rare as a bridge type due to higher costs compared to a triangulated truss, it is commonly employed in modern building construction as it allows the resolution of gross shear forces against the frame elements while retaining rectangular openings between columns. This is advantageous both in allowing flexibility in the use of the building space and freedom in selection of the building's outer [[curtain wall (architecture)|curtain wall]], which affects both interior and exterior styling aspects.

=== Waddell truss ===
[[Image:Waddell "A" Truss Bridge, Spanning Lin Branch Creek, Missouri cropped.jpg|thumb|Waddell "A" truss bridge, assembled in 1898]]
{{Main|John Alexander Low Waddell}}
Patented 1894 ({{US patent|529220}}); its simplicity eases erection at the site. It was intended to be used as a railroad bridge.

One example was the [[Waddell "A" Truss Bridge (Parkville, Missouri)|Waddell "A" Truss Bridge]] in [[Parkville, Missouri]].

=== Warren truss ===
{{see also|Warren truss}}
[[File:Warren truss.svg|thumb|A [[Warren truss]]]]
The '''Warren truss''' was patented in 1848 by [[James Warren (engineer)|James Warren]] and Willoughby Theobald Monzani, and consists of longitudinal members joined only by angled cross-members, forming alternately inverted [[Triangle|equilateral triangle]]-shaped spaces along its length, ensuring that no individual [[strut]], beam, or [[Tie (engineering)|tie]] is subject to bending or torsional straining forces, but only to tension or compression. Loads on the diagonals alternate between compression and tension approaching the center, with no vertical elements, while elements near the center must support both tension and compression in response to live loads. This configuration combines strength with economy of materials and can therefore be relatively light. The girders being of equal length, it is ideal for use in prefabricated modular bridges. It is an improvement over the Neville truss which uses a spacing configuration of [[Triangle|isosceles triangles]].

=== Whipple truss ===
[[File:Whipple-truss.svg|thumb]]
[[File:Triple-whipple-trus.svg|thumb]]
[[Image:Bridge L-158, Goldens Bridge, NY.jpg|thumb|[[Bridge L-158]], a double-intersection Whipple rail truss over the [[Muscoot Reservoir]] in [[Golden's Bridge, New York]]]]
A '''Whipple truss''', named after its inventor [[Squire Whipple]], is usually considered a subclass of the Pratt truss because the diagonal members are designed to work in tension. The main characteristic of a Whipple truss is that the tension members are elongated, usually thin, and at a shallow angle, and cross two or more bays (rectangular sections defined by the vertical members).  An example of the double-intersection Whipple truss is [[Bridge L-158]] in [[Golden's Bridge, New York]].

=== Wichert truss ===
[[File:Pittsburgh IMG 20150308 184143 (16653784330).jpg|thumb|[[Homestead Grays Bridge]] over the [[Monongahela River]] in [[Pittsburgh]]]]
The '''Wichert truss''' is a modified type of [[Continuous truss bridge|continuous truss]] which is [[statically determinate]] and helps avoid some of the other shortcomings of continuous trusses.<ref>{{cite book |last1=Steinman |first1=D. B. |title=The Wichert Truss |date=1932 |publisher=D. Van Nostrand Company, Inc. |location=New York |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015025958565 |access-date=August 29, 2022}}</ref> It was patented in 1930 by [[Pittsburgh]]-based civil engineer Edward Martin Wichert (1883–1955).<ref>{{cite book |title=Historic Highway Bridges in Maryland: 1631-1960, Historic Context Report |date=1995 |publisher=Maryland Department of Transportation State Highway Administration |url=https://www.roads.maryland.gov/OPPEN/V-Wicher.pdf |access-date=August 27, 2022 |chapter=The Wichert Truss}}</ref><ref>{{cite news |title=E. M. Wichert Services Set For Tomorrow |url=https://www.newspapers.com/clip/108547356/pittsburgh-post-gazette/ |access-date=August 29, 2022 |work=Pittsburgh Post-Gazette |date=March 23, 1955 |via=Newspapers.com}}</ref>

The defining feature of this truss type is a hinged [[Kite (geometry)|kite-shaped]] section above each intermediate support.{{Citation needed|date=April 2023}} Only about ten Wichert truss bridges were ever built, mostly in Pennsylvania and Maryland. Of these, one of the best known is the [[Homestead Grays Bridge]] in Pittsburgh.<ref>{{cite journal |last1=Wilson |first1=Helen |last2=Wilson |first2=Todd |title=From Browns to Grays: Evolution of the Homestead Grays Bridge |journal=Historic Bridge Bulletin |date=November 2017 |volume=4 |issue=3 |pages=5–9 |url=http://historicbridgefoundation.com/features/bulletin/hbfbulletin1117.pdf |access-date=August 27, 2022}}</ref>

==Video==
[[File:Crossing the Willamette River and Entering Lane County on Oregon Hwy 99E.ogv|Driving across a truss bridge in [[Lane County, Oregon]]]]
Driving across a truss bridge: The video shows the roadway perspective of a through truss bridge over the [[Willamette River]] in [[Harrisburg, Oregon]]. The bridge features three simply supported Parker Truss spans.

== References ==
* {{cite web |url=https://www.nps.gov/subjects/heritagedocumentation/upload/HAER-Truss-Poster_508.pdf
|title=Trusses: A Study by the Historic American Engineering Record |access-date=2024-12-31 |author=Historic American Engineering Record |author-link=Heritage Documentation Programs |year=1976 |publisher=National Park Service }}

== Footnotes ==
{{reflist}}

==External links==
{{Commons category multi|Through truss bridges|Truss drawings}}
* [http://www.historicbridges.org Historic Bridges of Michigan and Elsewhere] – Many photos of truss bridges are available on this informative and mainly truss-focused bridge website.
* [https://web.archive.org/web/20140305164010/http://www.iowadot.gov/historicbridges/construction.asp Historic Bridges of Iowa] – An illustrated list of different architectural bridge types found in Iowa, US. Many of these are truss bridges.
* [http://www.bridgehunter.com Historic Bridges of the U.S.] – An enormous database of historic bridges. Over 17,400 truss bridges are listed here.
* [http://www.oldohiobridges.com Iron and Early Steel Bridges of Ohio] A comprehensive inventory of all remaining truss bridges in Ohio. Includes maps, photos, and invites visitor assistance in identifying extant or demolished bridges.
* [https://web.archive.org/web/20060905130514/http://matsuo-bridge.co.jp/english/bridges/basics/truss.shtm Matsuo Bridge Company: Bridge Types – Truss]
* [https://rosap.ntl.bts.gov/view/dot/35693 Management Plan for Historic Bridges in Virginia: The 2017 Update]—Virginia Department of Transportation's plan for managing its historic bridges, including metal truss bridges. The update includes sections on study findings such as "General Issues Regarding Metal and Metal Truss Bridges (Including Potential Life Span)," "Coatings Issues for Metal Truss Bridges: Painting, Metallizing, and Galvanizing," and "Truss Bridge Capacity and Overloading Potential."
* [http://structurae.de structurae.de] The [[Structurae]] database on bridges.

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