Talk:Truss bridge

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[edit] 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)the truss is so cool.

[edit] 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)

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)

[edit] 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)

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)

[edit] 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)

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)

[edit] First Iron Truss Bridge

In 1841, a patent was issued to Squire Whipple, for the invention of the first Iron-Truss Bridge.[2]

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

[edit] 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)

[edit] 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)

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)
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)
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)
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)
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)

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)

[edit] 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)

[edit] 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)

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