Talk:Truss

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Untitled[edit]

Unless I am very much mistaken, this article is actually about statically determinate trusses. Article needs to make the distinction between this and indeterminate trusses and add analysis techniques for the latter. Cutler 13:55, Aug 7, 2004 (UTC)

The Vierendeel truss description sounds like a ladder333. Is this correct? And if so, how does a Vierendeel truss transmit shear loads? --Commander Keane 14:51, 4 Feb 2005 (UTC)

Yes. I looked at the pictures on the Vierendeel web site, and it looked like there were 2 main types:

  • "ladder" types -- horizontal top and bottom, connected by periodic vertical members. It looks like it transmits shear loads (which on other trusses are transmitted by diagonal beams or diagonal steel cables) by having wide vertical members and tall horizontal members -- the side of the bridge looks more like a solid sheet of metal with rounded-square portholes cut into it.
  • "arch" types -- the top looks like a parabolic arch (although we know it must really be a catenary arch). Strings hang straight down from it to hold the deck, with the strings varying in length just enough to make the deck horizontal. There are no major shear loads.

I think of a truss as being made up of pin-connected struts (therefore having only tension and compression, without having shear). Most real structures have at least some shear, and are not pin-connected, but they're close enough to being a truss that classic truss theory is adequate to analyse them. But the "ladder" type Vierendeel "truss" can't be analyzed by classic truss theory. I would tend to say it is technically not really a truss. But then, what do we call it? A bridge (or any other structure) can be

  • a statically determinate truss (no shear)(when external loads are zero, has zero strain),
  • a statically indeterminate truss (still no shear)(when external loads are zero, may still have "internal" strain), or
  • a _____ (what???), which has shear (which includes these Vierendeel things).

--DavidCary 02:25, 6 Feb 2005 (UTC)

styles[edit]

I think I'll eventually work on a section about different truss designs such as King Post, Queen Post, Howe, Pratt, Warren, Parket, Petit, etc. Cacophony 20:56, 7 February 2006 (UTC)[reply]

Lighting Trusses[edit]

There's also the use of trussing in most stage lighting environments - hanging the cans, lights, etc off lightweight trussing. AMe 12:05, 19 May 2006 (UTC)[reply]

Statics of trusses[edit]

The material on verticals and their role in stabilising the compression chord is very unclear as currently written. I'd like to get some time to rewrite this to cover (briefly) the role of the truss web members in carrying global shear, in supporting the lower chord against local bending, and in stabilising the top chord via u-frame action, where top bracing isn't present. One for a rainy day ... Kvetner 23:08, 5 October 2006 (UTC)[reply]

Howe truss[edit]

The article Howe truss is a redirect to this page, yet no mention of Howe is given. -- 15:21, 5 January 2007 (UTC)

I changed the redirect to a better target. --NE2 23:18, 23 September 2007 (UTC)[reply]

The gallery shows a "Howe truss in a commercial building", but the linked article states that a Howe truss is a bridge! Which one of these is wrong and which is right? yoyo (talk) 03:02, 13 September 2021 (UTC)[reply]

Snafu at foot of page[edit]

The final paragrap;h, beneath the very large image, appears to relate to a missing diagram. What's going on? Fix needed. --Tagishsimon (talk) 21:04, 29 August 2008 (UTC)[reply]

You are right. It was added by an anonymous editor on August 5, 2008. I will move the text here until it can be determined if it is appropriate to put back into the article. - ¢Spender1983 (talk) 04:33, 30 August 2008 (UTC)[reply]

the member AB actually makes contact on the left side of the pin , although the force AB is drawn from the right side and is shown acting away from the pin. Thus, if we consistently draw the force arrows on the same side of the pin as the member , then tension side (such as AB)will always be indicated by an arrow away from the pin , and compression (such as AF)will always be indicated by an arrow toward the pin.

— anonymous editor

Bell Ford Bridge[edit]

The claim is made that the Bell Ford Bridge was the last Post Truss bridge in the world. Do we know if a Post Truss differs from a King Post Truss or a Queen Post Truss? Anyone care to help out the BFB article by addition of a definition or ointer to a definition of a post truss? thanks. --21:04, 29 August 2008 (UTC)

I am responding on Talk:Bell Ford Bridge so that the discussion is kept with the article. - ¢Spender1983 (talk) 00:13, 4 September 2008 (UTC)[reply]

Merge with Truss Bridge?[edit]

There is a much more exhaustive list of truss types in the Truss bridge article. Should there be some sort of merger? Lars (talk) 01:20, 26 May 2009 (UTC)[reply]

Created article List of truss types for this purpose Lars (talk) 02:49, 26 May 2009 (UTC)[reply]
I don't think they should merge. There is enough info for two articles. The List of truss types article you have started does not have enough room for prose (in a table) to discuss the particulars of individual truss types. - ¢Spender1983 (talk) 22:44, 27 May 2009 (UTC)[reply]
Yeah, you're right. I'm going to get rid of the "description" column in the List of truss types article. I'd like to sort out all the names alphabetically, but I might just leave it is a sortable table instead. Lars (talk) 13:19, 28 May 2009 (UTC)[reply]

Etymology of Truss[edit]

Where does the word come from? Was it named after a German engineer named Truss? 216.99.219.238 (talk) 05:51, 18 September 2009 (UTC)[reply]

Lenticular truss, William Douglas vs. Brunel vs. Pauli[edit]

"Lenticular trusses, patented in 1878 by William Douglas": In Great Britain, the "Lenticular truss" was used by Isambard Kingdom Brunel for the Saltash Bridge, buildt during the years 1854-1859. In Germany, this type of truss is known as "Pauli-Traeger", named after Friedrich August von Pauli, who constructed the railway bridge of Grosshesselohe, buildt during the years 1851-1857. The merits of a William Douglas seem to be restricted to introducing this construction to the United States. http://en.wikipedia.org/wiki/Royal_Albert_Bridge http://de.wikipedia.org/wiki/Friedrich_August_von_Pauli http://www.elkage.de/src/public/showterms.php?id=265 http://de.wikipedia.org/w/index.php?title=Datei:Munich_Grosshesseloher-Bruecke.jpeg&filetimestamp=20060305130647 -- Riggenbach (talk) 13:53, 15 May 2011 (UTC)[reply]

Camel-case?[edit]

Doesn't this article suffer heavily from camel-case? I mean, "truss" is not a proper noun, nor are "members", "joints", or "post frame structures". HandsomeFella (talk) 10:10, 14 December 2011 (UTC)[reply]

incorrect picture(s)?[edit]

there is a picture labeled "howe truss" showing timber framing on a commercial structure... the horizontal members appear to pass right through the verticies(joints). Thats not a truss. Truss members are connected at thier extremities only. No member is continuous through a joint. [1]

Yes, the picture is of cantilever post and beam construction, there is no Howe Truss visible. (is that a 'false' truss, as in a 'false' eave?)
  • many of the small diagrams also appear to incorrectly show members passing through joints. Thats just not right! Please fix this!
  • Fencelizard (talk) 16:26, 24 November 2014 (UTC)[reply]

References

  1. ^ Vector Mechanics For Engineers (Statics) Fifth edition. Ferdinand P. Beer, E. Russel Johnston, Jr Section 6.2 Definition of a truss. pp224
Yes, that picture has major problems. The front "truss" appears to be purely ornamental, as it has no apparent means of transferring load to the ground. The side trusses appear to be similar to Pratt trusses, cantilevered off the posts at their center point (which is not usual for a truss). Either way none of them are actually Pratt or Howe trusses, since they use mortice and tenon joinery (you can see the fastenings in the chords) which is specifically excluded in the Pratt and Howe patents; and since they don't transfer load to their ends.

Warren truss[edit]

The Warren truss is the most iconic and archetypal of all modern trusses. Where is it? — Cheers, Steelpillow (Talk) 17:51, 26 November 2015 (UTC)[reply]

Floor trussing[edit]

Anyone know of a good location to add some details on floor trussing in architectural and building design? I did some basic research on failure and sagging in floors and deflection in trussing. Is this something to go in this article or maybe another new article?

Shaded0 (talk) 02:09, 19 April 2016 (UTC)[reply]

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Definition?[edit]

As it stands, the article states that a truss, "consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object".[1]

That's a very narrow definition. IMHE, that's the definition of a pin-jointed truss, not merely any truss. "two-force members only" implies that each member of the truss has only forces on it, no bending moments.[2]

There are many types of "truss" (some included here) where the definition is clearly broader than that. The members can be more complicated than simple two-force, pin-jointed members. These are difficult to analyse, so used to be avoided. However they are still trusses, they do exist and we need to cover them.

What should we do? I think the lead needs a re-write to emphasis the distinction of trusses in general, and pin-jointed trusses meeting this stricter definition, and their dominance in civil engineering. Do we have any useful references to give a broader viewpoint here? Andy Dingley (talk) 11:49, 27 June 2018 (UTC)[reply]

References

  1. ^ Plesha, Michael E.; Gray, Gary L.; Costanzo, Francesco (2013). Engineering Mechanics: Statics (2nd ed.). New York: McGraw-Hill Companies Inc. pp. 364–407. ISBN 0-07-338029-6.
  2. ^ If each member is only attached by pin joints, bending forces cannot be applied, as the joint would simply rotate instead.
Yes, the lead does need a rewrite, to address the issues you raised, and also to avoid misleading readers that the two nodes are what _defines_ a two-force member. (The article presently reads 'A "two-force member" is a structural component where force is applied to only two points. Although this rigorous definition allows the members to have any shape connected in any stable configuration, ...'.) yoyo (talk) 02:45, 13 September 2021 (UTC)[reply]
Hmm, every text I check defines a truss as being designed to have only tensile and compressive loads. I think the article definition is correct. A structure which allows bending loads is a frame, not a truss. (I note that the article on "pin-jointed truss" which Andy links no longer seems to exist, which is probably reasonable since that's more a distinction of construction technique than design).
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