Talk:Truss bridge

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Price of steel vs labour

I'm not sure I agree with this recently added comment. In Europe and I understand elsewhere, the cost of steel has increased enormously in recent years, but in most places the cost of labour is considerably larger, which is one reason we weld girders in automated machines rather than employ people to rivet them. Can I suggest that the wording be amended to note that the "relative" price of materials and labour will affect design decisions, and remove the reference to "decreasing"? --Kvetner 11:53, 29 November 2006 (UTC)[reply]

History in the US seems missing

Various reversions didn't always get all the way back and it looks like we've lost some content. will investigate shortly if someone doesn't beat me to it. ++Lar: t/c 18:16, 11 January 2007 (UTC)[reply]

Sorted, i think. Normally I'd just revert but it was so bad I figured I better give a heads up in case there was substantive intermediate change lost. ++Lar: t/c 19:31, 11 January 2007 (UTC)[reply]

2nd paragraph

"In the bridges illustrated above the vertical members are in tension, lower horizontal members in tension, shear, and bending, diagonal and top members are in compression." This sentence doesn't seem to reference any illustrations on the page, I'm assuming it has been copied from elsewhere, or the illustrations subsequently removed. Does anyone have any good diagrams illustrating the forces on truss members? RoscoHead 00:07, 13 January 2007 (UTC)[reply]

Well spotted. That text looks changed by LeonardG and others to now refer to the image in the infobox. Perhaps what happened is that the image previously was at the top of the article, but when the infobox was added, the text wasn't changed to refer to where the image was? I am not sure, you'd have to check the history. I'm not a bridge expert by any means (my Brown truss article had the tension and compression all wrong, sadly) but I agree that force diagrams for various truss types would be nice. The West Point bridge simulation program (which I used to make the Brown truss illustration and which you can get free from the US Army here: [1] ) will show forces but it has the flaw of only allowing pinned connections, you can't have a long member with a connection in the middle, as it doesn't seem to simulate bending moments. I tried drawing something in Inkscape by hand, but it would have been a very long and slow process so I gave up. It would be nice if someone created these for the common truss types (I have been toying with the idea of writing articles for Pratt, Howe, Warren, Bowstring, etc... I think those are the most common truss types but am not sure) which is why the article has redlinks, I put them there I think... Commons does have a category though: Commons:Category:Truss drawings, but they lack force annotation for the most part. ++Lar: t/c 13:57, 13 January 2007 (UTC)[reply]

Pratt? Expansion request.

Regarding this sentence: "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." This sentence is the only place in the article that a Pratt design is mentioned. What is it? My reason for asking is that I want to write an article about a specific bridge on the National Register of Historic Places; my documentation describes it as a "Pratt Through Truss bridge," and I'd like to be able to internally link to an article which would explain what that is. Could anybody add a bit about it? (Especially nice would be source citations, which the article currently lacks and is worse for it.) Thanks for any help. --Malepheasant 09:02, 26 January 2007 (UTC)[reply]

The main truss article really needs expansion to cover the various truss types properly. In the meantime, the external links and Wikimedia commons links on the truss bridge page will at least show you what a Pratt truss looks like. I'll see if I can get time to do an update on some common truss types but have a lot of other things I need to do at present. -- Kvetner 09:47, 26 January 2007 (UTC)[reply]

The Hawker Typhoon (and probably other aircraft) used a Pratt truss setup for the inner spars of the wing. [2]. 2001:56A:F414:D300:6581:1AE5:5338:5FD0 (talk) 06:37, 18 December 2015 (UTC)[reply]

First Iron Truss Bridge

In 1841, a patent was issued to Squire Whipple, for the invention of the first Iron-Truss Bridge.[3]

Do you think we could add a mention about this invention? Thank you. Korismo 15:38, 23 August 2007 (UTC)[reply]

Deck Truss

Being a layman concerning bridge design, I may be wrong, but shouldn't the example for a deck truss bridge be one like Image:I35W Bridge.jpg, with the road bed at the top of the structure, rather than Image:Pulaski Skyway full view.jpg where a lot of the truss structure is higher than the roadway? Or am I misinterpreting the definitions?--Appraiser 13:49, 27 August 2007 (UTC)[reply]

Types of truss

I found Historic Bridges of Iowa which enumerates a bunch of different truss types. I'm trying to get permission to lift a bunch of its content. Is there a more public source of this information? Denimadept 20:06, 28 August 2007 (UTC)[reply]

Something is needed. For example, the term "Warren Truss" is used several times in the article without a definition (and "Warren Truss" pseudo-redirects here...--Rehcsif 18:17, 12 September 2007 (UTC)[reply]

It looks like an area for improvement. List "types of truss" with a basic image (not a photograph) of the truss and an explanation of how that truss is different from some predecessor truss. I'm no expert on this issue. Looks like a need for Super Reference Librarian! - Denimadept 18:49, 12 September 2007 (UTC)[reply]

There. From a couple of the External Links, I've extracted a list of different truss types. Now for explanations and illustrations. - Denimadept 19:00, 12 September 2007 (UTC)[reply]

I notice that someone got rid of the hierarchy I imposed to show the relationships of truss to progenator truss type. Is it that such a relationship is an opinion rather than based on which-came-first, or is there some other reason? - Denimadept 21:16, 17 September 2007 (UTC)[reply]

Also, I notice that the Brunel Truss and the Lenticular truss are listed separately but point to the same bridge. Should these be merged? - Denimadept 21:19, 17 September 2007 (UTC)[reply]

Maybe this is a project (WP:BRIDGE? what ever the Civil Engineering project is?) discussion but I think having a truss list is way overdue. Our truss coverage must be spotty if we have an article on Brown truss which is really minor (because I needed it for a covered bridge article) but not on Warren??? Goodness. I'd support indentation if it was referencable except that really, the thing would be more of a acyclic directed graph diagram, some trusses have more than one forebear, etc. Worth trying though. ++Lar: t/c 20:52, 19 September 2007 (UTC)[reply]

Bollman Truss bridge image

It's in two places. While it seems to belong there as the article is currently written, I think it'd make more sense to have it only in the location documenting the Bollman Truss. - Denimadept (talk) 22:23, 31 January 2008 (UTC)[reply]

Examples

For someone with Photoshop, here are some examples that you could use as a bases for more graphics. Aboutmovies (talk) 09:24, 19 April 2008 (UTC)[reply]

Interesting handout you've got there. Good stuff. - Denimadept (talk) 14:24, 19 April 2008 (UTC)[reply]

Use of the HAER Publication on Truss Types as a Reference Document

The article has been tagged with {{RefImprove}} since March 2, 2008. In short, the article needs better verifiability by policy. Recently I found the following, which I consider to be an excellent source/reference for this article.

Historical American Engineering Record (1976). "Trusses: A Study by the Historical American Engineering Record" (pdf). National Park Service. Retrieved 2008-07-20. {{cite web}}: Cite has empty unknown parameters: |accessyear= and |accessmonthday= (help)

It seems like this is causing an edit war, so this discussion is started. I will begin with the consideration if this is a reliable source.

The content guideline for reliable source reads as follows:
Wikipedia articles should use reliable, third-party, published sources. Reliable sources are credible published materials with a reliable publication process; their authors are generally regarded as trustworthy or authoritative in relation to the subject at hand. How reliable a source is depends on context. As a rule of thumb, the more people engaged in checking facts, analyzing legal issues, and scrutinizing the writing, the more reliable the publication.

The source is reliable. The Historic American Engineering Record is a Heritage Documentation Program of the National Park Service, an agency of the US government. This is NOT a fly-by-night source. It was founded in 1969. It is reliable in that the program has a set of standards for publication - available here and published in the federal register. It is reliable in that it is recorded (published) in the Library of Congress. Because their purpose is to document engineering history and because they have an established process for publication, I consider them and their works to be authoritative.
If there is any disagreement in the reliablility of this source, I request it be taken to Reliable sources/Noticeboard for discussion. - PennySpender1983 (talk) 00:07, 24 July 2008 (UTC)[reply]

The next question is if the HAER source supports facts in the article.

The content guideline for reliable source reads as follows:
Sources should directly support the information as it is presented in an article and should be appropriate to the claims made.

This needs to be addressed because when I inserted the source as a footnote reference, the deleting editor said that the source "doesn't contain the descriptions that you've pasted the url onto".

Since much of the information is the article is graphic, this source does directly support the facts presented in the article.
Also, the HAER source document provides written information the supports the facts given in the article. For instance the article opens with a discussion that the members (or structural elements) in a truss bridge act in either compression or tension. The HAER document supports this fact by saying the same thing with different wording.
The next example is as a reference for the claim the the Town's lattice truss was in use as of 1820. The HAER document clearly supports this fact. OK, let's keep going, does the HAER document support the truss definition of through, deck and pony truss types. Well, it says the exact same thing as the article, so yes.

Do I need to go on? Clearly the HEAR publication is a source for the facts presented in this article. I am unsure why it would be claimed otherwise.

The next claim by the deleting editor is that the HAER publication does not provide any references to its sources. This claim is downright outlandish. The HAER publication clearly lists TWELVE sources on the lower right side. These references date from 1881 to 1976, and include works by well-known bridge engineers like John Alexander Low Waddell.

Last, it should be discussed that this source does NOT get listed in the "External Links" section. Style guidelines allow for this to be placed in either the reference section or the footnotes (via in-line citations).

The External links-References and citation style guideline says
Sites that have been used as sources in the creation of an article should be cited in the article, and linked as references, either in-line or in a references section. Links to these source sites are not "external links" for the purposes of this guideline, and should not be placed in an external links section.

What would be the reason to place this in the External Links section when it is clearly a reliable source that can verify information presented in the article? Since the article is tagged as needing sources, that should be the goal—not to increase the number of external links. - PennySpender1983 (talk) 01:36, 24 July 2008 (UTC)[reply]

short: your comments amount to saying that each of the existing external links should be used as a reference, without regard to context. The HAER poster is useful, but it is not in itself a primary source. Not all reliable sources are apt. Tedickey (talk) 10:08, 24 July 2008 (UTC)[reply]

You really do not make a case for this not to be a reference document for the article. I am not asserting that all of the external links qualify to be references. I do not understand (nor do you explain) how you could think that I am trying to conclude this.

The facts remain: (1) The Truss bridge article contains pictures of bridge types. And, (2) the HAER document provides verification of these pictures. Therefore, it is a logical conclusion that the HAER document is fitting as a reference.

If you disagree, please give more specific and logical reasoning. - PennySpender1983 (talk) 04:10, 25 July 2008 (UTC)[reply]

I'm not fully understanding the problem here. Is the information on the page being disputed, or just the referencing for the information? -- ☑ SamuelWantman 05:59, 25 July 2008 (UTC)[reply]

It is the referencing. The article is tagged for {{RefImprove}}. I added this HAER document as a reference and it has already been moved to the external links twice by another editor (check the history for his comments there in addition to above). I would like some concensus that this document by HAER is more appropriate in the reference section than the "external links". If we don't add references, how do we ever remove the tag. - PennySpender1983 (talk) 06:34, 25 July 2008 (UTC)[reply]

It looks like an excellent reference to me. It is a tertiary source, which is just fine. -- ☑ SamuelWantman 09:03, 25 July 2008 (UTC)[reply]

Why not find a suitable reference, rather than a poster? And my question about what makes this authoritative versus the other external links has not been addressed. Tedickey (talk) 10:04, 25 July 2008 (UTC)[reply]

Do you have suggestions for better references? The article needs references. This seems a reliable source, and the material sound.. There may be other references as well, please add them!... but I see no harm in using this one. While it's a reference, it has not been cited inline as we normally prefer. Some inline cites for each different truss type ought to be dug up but that's rather a big job... till then this is better than no ref at all. Once that happens, this could be moved to "for further reading" or "external links", but not yet. (A notice on my talk page brought me here, by the way... bridges were an early wiki-interest of mine) ++Lar: t/c 11:58, 25 July 2008 (UTC)[reply]

One of my deleted edits inserted the HAER publication using in-line citations. I found seventeen places in the article where I thought it supported facts presented. To me, this is excessive and I would follow the style guideline that allows entry as a general reference.

Citing sources says, If a source supports a significant amount of the material in an article, it may sometimes be acceptable to simply add the citation at the end. It serves as a general reference, not linked to any particular part of the article. This is more likely to be appropriate for relatively undeveloped articles or those covering a very simple or narrow topic.

I have not seen too many footnotes where the number of times used gets that high. - PennySpender1983 (talk) 17:17, 25 July 2008 (UTC)[reply]

This is a broad topic and a relatively developed article (I was just about to rate it a B because I think it's beyond start) so that may not apply exactly. But "inline or at the bottom?" is a side issue to my thinking. The point is, this is an acceptable reference. Removing it seems wrong. If more specific references can be found and included, great. Please do, Tedickey. But please don't edit war to remove a reference. PS is right, this is a valid reference in my view. 18:47, 25 July 2008 (UTC) ++Lar: t/c

The form of the reference is irrelevant. In a number of articles, I use the ASCE 2008 Bridges calendar as a reference since it happens to contain the information. Primary sources are best, but they're not always available. We use what verifiable sources we can get. - Denimadept (talk) 13:18, 25 July 2008 (UTC)[reply]

I agree the HAER poster is a suitable reference until something better can be found, it's from an authoritative source and from a quick look I can't see any obvious errors of fact. A suggestion for better references might be "American Bridge Patents: The First Century" by Emory Kemp, if anyone has time to go through it (my own time on Wikipedia is unfortunately next to nil at present). -- Kvetner (talk) 12:34, 30 September 2008 (UTC)[reply]

What made the truss design the fault? - Text moved here

I have moved this text below from the article to this talk page because it does not seem to meet WP:NPOV or WP:NOR.

Faults in the design of the Howe truss were proved to be the cause of several railroad accidents in the United States. The most notable of these were the "Ashtabula Horror" in Ashtabula, Ohio, in 1876, and the "Forest Hills Disaster" in Boston, Massachusetts, in 1887.^{[citation needed]}

The reason for moving the text is that it seems to assert that the prototypical design of the Howe truss was at fault for the accidents. If you read Ashtabula River Railroad Disaster, it places more blame on the use of steel and the lack of testing and inspection. Also, this reference for the Forest Hills Diaster again places more blame on the material, inspection and lack of knowledge of the particular designer about using iron in lieu of wood.

This makes the proposed text seem like it does not have a neutral point of view and may constitute original research if no references can be provided.

For these reasons, it seems that placing any text into the section about the generic Howe truss about these accidents will require proper qualifiers.. Any other thoughts? - ¢Spender1983 (talk) 22:24, 7 September 2008 (UTC)[reply]

A Question

So what does that make this kind of (road) bridge? —Preceding unsigned comment added by Stuffed cat (talk • contribs) 17:26, 25 November 2008 (UTC)[reply]

It looks like a wrought[?] iron arch. It isn't made up of beams, so as I understand it it's not a truss bridge. Of course it would help if the footbridge weren't obstructing the view. Imaginatorium (talk) 18:28, 30 June 2012 (UTC)[reply]

Another truss bridge soon to be gone.

The truss bridge used for northbound traffic on Interstate 95 between Fruitland and Payette, Idaho is soon to be removed to make way for either a second two lane concrete bridge or widening of the existing concrete two lane bridge currently used for southbound traffic. Right now the truss bridge is closed and two way traffic is routed over the southbound bridge. Bizzybody (talk) 06:56, 31 August 2010 (UTC)[reply]

Howe truss

Does this have single diagonals in compression (as this article suggests), or an X lattice of paired struts? per Houck Covered Bridge or File:Howe Truss Pine Bluff Bridge, Spanning Big Walnut Creek, CR 950N, Bainbridge vicinity, Putnam County, IN00006a.jpg Surely the X lattice is a Town truss instead?

What's a "Modified Howe truss"? Is that where the X frame arises?

Apart from the many timber examples, are there any in iron? Any cast iron ones? Andy Dingley (talk) 00:46, 16 October 2012 (UTC)[reply]

The Houck Covered Bridge looks like a Brown truss. I can't speak to the other. I know of a metal Town lattice truss. - Denimadept (talk) 05:23, 16 October 2012 (UTC)[reply]

K truss

Can someone please explain the virtues of the K truss. Looks a right horrible thing IMHO, sticking a sideways bending force into that vertical. What's the point to it? Andy Dingley (talk) 17:10, 10 September 2013 (UTC)[reply]

Need for Protection

I believe that we definitely need to make this article semi-protected as soon as possible. The revision history, to me just looks like a bunch of vandalism edits being reverted. I think it would spare some time for people if we protect it. Leoesb1032 (talk) 01:00, 5 December 2013 (UTC)[reply]

Agreed. Andy Dingley (talk) 01:22, 5 December 2013 (UTC)[reply]

Warren truss

This article and its accompanying diagram describes the Warren truss as containing no vertical elements. However, I have seen plenty of truss bridges that are widely described as Warren truss bridges and that do in fact have vertical elements. For example, the lead image of this article appears to be a modification of the Warren design that contains vertical elements. Is this properly described as a modified Warren truss, or is it considered another design altogether? DiverDave (talk) 23:00, 2 June 2014 (UTC)[reply]

To some extent, trusses follow the styles they do, not because of any structural virtue, but because of their simplicity of calculation. Something like a Warren or Pratt truss is long-studied and well understood. There is a standard calculation method for them, the designer simply has to plug in the relevant figures for that site. In many small cases (industrial gantries etc), trusses are an off the shelf product and the ironwork fabricator offers them at standard sizes, with known capacities. These standard designs and standard calculation methods largely assume long, narrow trusses where they begin to approximate the infinite repeated cell approach. End effects can be ignored, or at least over-compensated. Something like Abetxuko Bridge could have been built from around 1940 onwards (cheap electric welding), but it could not have been designed until quite recently, as its non-uniform shape requires the entire structure to be modelled as finite elements.

The lead image here is confusing as it's far from a typical truss. It has too few bays and depends too much on end effects. It's a fine way to cross a narrow river, but it's not an illustrative example for the engineering background and history of the standardised truss.

As to the Warren truss, then Warren trusses don't have verticals. If they do have verticals, they stop being Warren trusses for the purposes of their design calculations. As the Dee accident showed, even adding bracing elements can weaken a design. Now there are certainly trusses that are like Warrens with verticals, and they are even called Warren trusses (it's typical that non-standard designs attract standard names, even when inappropriate). For the purposes of this article though, we should limit ourselves to the Platonic ideal of the Warren truss and ignore the variant forms. In Warren truss itself we might go far enough to discuss variations, but this is the overview article and clarity is a great virtue. An encyclopedia's goal is to educate, not (perhaps surprisingly) to define formally, and where in some cases those two do give rise to conflicts, we should choose clarity and education over listing every obscure outlier. Andy Dingley (talk) 09:16, 3 June 2014 (UTC)[reply]

Thank you Andy for your (very articulate!) explanation. Does this mean that the Manhattan Bridge does not in fact utilize the Warren truss in its design? If not, then how would we correctly describe the type of truss it uses? DiverDave (talk) 15:04, 3 June 2014 (UTC)[reply]

I'm not familiar with that particular bridge and although you might choose to believe my crazed ramblings, you certainly shouldn't quote them into articles without other WP:RS to support them. At first glance, the Manhattan bridge looks to be one of the not uncommon types of suspension bridge where the deck is stiffened with additional truss bracing. The majority of the weight is (it usually is, I haven't checked here) carried by the suspension cables so we still consider the bridge to be a suspension bridge overall. It's fair to say that it uses the Warren truss, but not to say that it is a Warren truss.

Many bridges are combinations of techniques. It's not possible to simply categorise them into a handful of types, especially not when the list of types is a list of basic geometries. There's a similar issue for through deck bridges, cantilevers and tied arches or bowstrings. A bridge may combine aspects of all these types and any categorisation ought to at least be on the basis of which is carrying the major loads, not just some incidental aspect. It can make it quite hard sometimes to find pictures of a "<foo> truss", where a particular bridge is a pure foo and nothing but the foo. Andy Dingley (talk) 15:59, 3 June 2014 (UTC)[reply]

Thanks again Andy for clarifying this issue! DiverDave (talk) 01:40, 4 June 2014 (UTC)[reply]

I dunno, Andy. For not knowing much, you sure manage to enlighten a great deal. :-) - Denimadept (talk) 00:52, 5 June 2014 (UTC)[reply]

Hey, i came for the same reason, that the Beaver Creek Bridge (Electra, Texas) has documentation showing its "Warren pony truss" design that includes vertical members and right angle triangles, not equilateral triangles. The equilateral triangle picture in this article needs to be replaced or supplemented. I will revise its caption now, at least. --do ncr am 18:30, 17 February 2017 (UTC)[reply]

Should the article explain or reference the parallel chord truss bridge, since it appears to be used in current construction?

I ran across current instances of a parallel chord truss bridge (http://www.westernwoodstructures.com/index.php/timber-bridges/pedestrian-bridges/). But this term is not part of the truss bridge article. The instances look like what the Wikipedia article calls a Neville truss, repeated isosceles triangles (though I could be wrong). But the article says Warren truss is superior to Neville. So some brief discussion of the term parallel chord, its relation to Neville (if I'm right), why it's still used despite Warren being superior, seems in order.

Richard31416 (talk) 21:57, 11 May 2015 (UTC)[reply]

If you could research that and modify the article with the cites you find, that'd be good. - Denimadept (talk) 23:08, 11 May 2015 (UTC)[reply]

"Parallel chord" is just a descriptive term relating to the fact that the top and bottom chords are parallel. It has nothing to do with the type of truss separating the chords. Nice ref for pictures of beautiful timber bridges, though. Meters (talk) 20:38, 3 November 2015 (UTC)[reply]

Camelback truss

The current section at Truss bridge#Parker (camelback) truss asserts without source that a camelback is a Parker truss where there are exactly five sections. However the NRHP-listed example given, Woolsey Bridge appears to have more than five sections in both of its spans. Also the NRHP-listed Ediceton Bridge (currently a redlink) has a 186 feet (57 m) span that is stated to be a Camelback through truss (NRHP document, but has more sections as can be seen in photos and Google street view. --do ncr am 21:30, 27 March 2017 (UTC)[reply]

It's all correct, as far as I can see.

A Pratt truss is a linear truss of repeated N bays, with their diagonals in tension. In lengths up to 50' wide, this is a simple design: the repeated bay is easy to make and the elements can be rolled in one length, then the whole truss shipped in one piece. It's also fairly easy to model mathematically. Its drawback is that the forces on it are greater in the middle but the truss section is constant, thus over-generous towards the ends (you don't really need that much steel and money at the ends).

A Parker truss is a Pratt truss that is polygonal, rather than linear. It's a combination of the Pratt truss and the lenticular girder, with the centre sections being deeper. The overall profile approximates the loads, so the truss is more "efficient" at just providing strength where it's needed.

A camelback truss is a Parker truss with 5 chords. It's the recognition that for "typically" sized Parker trusses of typical roads crossing typical rivers, then 5 chords is about the right number to use. It's an odd number because load distribution (which is relatively constant across the centre) means that a central horizontal chord is near enough as efficient as two. Three chords is too few (the end chords are necessarily shallow, so this would be a long linear centre with short ends - little different to a Pratt), seven too many (that's returning to a Parker, and symmetry encourages such a truss to use an even number of chords). Remember that all of these designs are early, pre electronic calculation for the loads, and so the design of such a truss is expensive, as well as its manufacture. The calculations for its design are simpler for fewer chords.

I think the confusion here is from bays vs. chords. A bay is the space between vertical uprights, filled by the diagonal tension member. A chord though is the number of bays (typically two) spanned by a single, straight upper element. All the bridges mentioned here so far have five chords, so are camelbacks. Andy Dingley (talk) 00:54, 28 March 2017 (UTC)[reply]

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Ithiel Town through truss

The Ithiel Town through truss is mentioned in the Keniston Bridge article. Is there anything distinctive about this structure?--Dthomsen8 (talk) 21:01, 27 January 2018 (UTC)[reply]

Yes, and that's why it has its own article. We already discuss the lattice truss form in this article and in Lattice truss bridge Meters (talk) 21:59, 27 January 2018 (UTC)[reply]

US History

Why is the Town lattice apparently the first truss bridge in the US according to the US History section? In every covered bridge book Ive ever read, the king and queen post were first, followed by the Burr arch truss. The Town lattice is usually presented as a more modern type. Even if you only want to talk about trusses developed in the US, and don't want to count the Burr arch truss because it's basically multiple kingposts and an arch, its not very useful as history. Forget kingposts, forget Burr, "the father of the covered bridge", all you need to know about early US trusses is that they were wood and invariably use iron rods for tension members; apparently the first and only type worth mentioning is the Town lattice of 1820. The end.

Actual text:

 Because wood was in abundance, early truss bridges would typically use carefully fitted timbers for members taking compression and iron rods for tension members, usually constructed as a covered bridge to protect the structure. In 1820 a simple form of truss, 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.

That is it. Nothing about the king/queenpost truss, Palmer or Burr truss, nothing about the Long truss, or the Howe truss. I don't see any point in this paragraph as written. I guess one could interpret it as "no REAL bridges were built in the US until 1850, because they were too busy mucking around with wooden trusses like the Town lattice".]

64.223.163.252 (talk) 19:53, 8 January 2021 (UTC)[reply]

"pin connected" joints

We have around 130 articles that use the term "pin-connected" truss and/or bridge, but no good place to link that. There is Pin joint which redirects to Revolute joint, but isn't really specific to bridges or trusses. There is also Pin jointed truss which redirects to Truss (no specific section), which has some technical details on joints and forces. This article mentions pin joints a coupld of times.

I found this blog which explains how pin jointed truss bridges were easy to assemble, had other drawbacks, were replaced by riveted joints around WWI. This kind of info should be in the encyclopedia somewhere. Is anyone more knowledgeable and have some better sources? MB 04:50, 30 August 2021 (UTC)[reply]

The big advantage to pin jointed trusses is that there can be no bending moments transferred at the joints. With some simplifying assumptions it is fairly easy to design a statically determinate pin-joined simple truss, in which each member is loaded only axially, and with a known load. We should probably explain this point in Revolute joint. Meters (talk) 05:23, 30 August 2021 (UTC)[reply]

That's all on the engineering side. I would also like to see more on application/history side. MB 00:14, 31 August 2021 (UTC)[reply]

Technology

What is truss bridge disadvantages — Preceding unsigned comment added by 41.116.199.213 (talk) 17:04, 16 February 2023 (UTC)[reply]