Talk:Cable-stayed bridge

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The biggest, or longest bridge is the one that connects Rio with Antirrio in western Greece. It is supposed to be finished today 24/5/2004 as there are only 36 meters left for the completion of the project. It will be open to the public after the Olympic Games as it has to be tested first. The bridge is cable-stayed, 2 225 meters long with four pylons. The openings are 286,560,560,560,286 meters in length. There are two approach viaducts, 392 meters on the Rio side and 239 meters on the Antirrio side. The deck is 27.5 meters wide. The foundations of the pylons go down 65 meters beneath the seabed. The seabed needed reeinforcing as it consists of clay. It can withstand impact with a tanker of 180 000 tonnes travelling at 18 knots and wind speeds of 265 kilometers per hour (winds of such speeds fall within the hurricane category)The pylons rise up to 227 meters above the seabed.

I would like to add that to the article but have insufficient data. Moreover i don´t have enough time. If anyone cares to make an inquiry i would be more than happy to help.

Jerry

Jerry, sounds like that bridge needs to be its own article. Unrelatedly, I think it might be good to split the example bridges into parallel vs. radial, but I'm not sure which is which. So far, the only radial one I know of is the Clark Bridge in Alton IL, but I don't think it has a WP entry yet. Ventura 06:00, 2004 Jul 10 (UTC)

Leonard added "but the advantage of not requiring firm anchorages to resist the pull.". I figure we should following this by saying something like "For this reason cable-stayed bridges are often used when one or both ends of the gap to be spanned ends in an elevated causeway"? (or something like that) -- Finlay McWalter | Talk 23:59, 4 Aug 2004 (UTC)

Some conventional suspension bridges also end in elevated causeway on at least one end, such as the southern end of the Golden Gate Bridge and the western end of the San Francisco-Oakland Bay Bridge. In these cases, the main cables are brought down at an angle below the causeway to where it is convenient to anchor them. Leonard G. 03:23, 5 Aug 2004 (UTC)

An anonymous user changed two pillar bridge comparison to suspension bridge to seven piller. I generalized and clarified. Note that conventional suspension bridges are not built with more than two towers between anchorages due to potential dynamic instablity. (Are there any examples to the contrary?) Note that the four tower western span of the San Francisco-Oakland Bay Bridge is actually two two-tower bridges with a massive central anchorage built on pilings into hard mud. Leonard G. 16:33, 10 Aug 2004 (UTC)

Is there any information on the history of cable-stayed bridges? What was the first bridge built, for instance?

I have made several edits to the page, including providing a very brief history largely drawn from Walther's book (cited in the bibligraphy). I've also amended some of the terminology to reflect what is generally used in the field. If anyone has any queries or objections, please discuss them here! -- Kvetner 21:59, 16 January 2007 (UTC)

[edit] Longest in world

I note a recent edit disputed the Rio-Antirio bridge's title as longest cable-stayed bridge in the world, suggesting that in fact the Sunshine Skyway Bridge is longer. This is a bit misleading - the Sunshine Skyway bridge is mostly an elevated viaduct, with only a relatively short cable-stayed section, which seems to be in no way record-breaking. The Rio-Antirio Bridge has the longest continuous length of cable-stayed deck, and the Tatara Bridge the longest single cable-stayed span. Before I try and clarify the article (to delete the claim that the Sunshine Skyway is the "world's longest cable-stayed concrete bridge"), does anyone have any other views? -- Kvetner 13:35, 6 March 2007 (UTC)

Going by the links in the list of largest cable-stayed bridges Rio-Antirio has cable-stayed spans of 286 m, 560 m x 3, 286 m whereas the Millau Viaduct has cable-stayed spans of 204 m, 342 m x 6, 204 m. So which is the longest cable-stayed suspended deck? Note that the list claims Rio-Antirio is the longest. -- Paddu 23:59, 25 April 2007 (UTC)
There is reason to discuss the total length of a bridge in its article. It is harder to build a cable stay span a mile from land than when the pylons are on the river bank. The height of the Millau span is an example of why the geography is important. It is an impressive bridge, but its construction was an engineering marvel because it was done so high above the valley floor. Check the Mackinac Bridge for an example of how to discuss total length versus longest (main) span. I would suggest something like this: the total length of the Sunshine Skyway makes it the longest bridge in the world with a cable-stayed main span. - SCgatorFan 00:18, 28 April 2007 (UTC)
I'm glad someone brought up the subject of the Sunshine Skyway. I was going to question the claim on this page that the Arthur Ravenel, Jr. Bridge is the longest cable-stayed bridges in the Western Hemisphere until I read your comments since the Sunshine Skyway is more than twice as long in actual length. But, I understand what you mean about the Sunshine Skyway being a long bridge that happens to have a cable-stayed span. If we're talking about span length, then yes, the Arthur Ravenel, Jr. Bridge is does have the longest span in the Western Hemisphere. Maybe that should be clarified on the page stating it has the longest span in the Western Hemisphere, rather than saying it's the longest bridge? -- BucsWeb 11:42, 16 May 2007 (UTC)
I read both articles again. I think that the Arthur Ravenel, Jr. Bridge is clear in saying its main span is the longest in the Western hemisphere. But when I read the Sunshine Skyway Bridge article, I remembered that the Skyway is a concrete mainspan (i.e., there are no steel girders used in the main span). Maybe the writer was saying that the main span is the longest concrete cable-stayed bridge. That would be a hard claim to prove or disprove. - SCgatorFan 01:57, 17 May 2007 (UTC)
As per List of largest cable-stayed bridges, "largeness" is usually (may be, controversially) measured by the "length" of the main span. Hence if one is talking about comparing main spans, may be one should use "largest" instead of "longest".
BTW any comments on the Millau Viaduct being "longer" than the Rio-Antirio Bridge, for which I've been waiting for quite a while?  :-) -- Paddu 09:19, 20 May 2007 (UTC)
I don't think we should use "largest" as it's never clear - "longest" or "tallest" at least have precise meanings. This page [1] claims the Millau as the longest cable-stayed bridge, and given the spans cited on the Millau and Rio-Antirio pages, that would seem to be right. I suggest you go ahead and amend to suit. I do have a technical article at work by Michel Virlogeux, Millau's designer, which covers several large multi-span cable-stayed bridges and may be a useful reference - I'll try and remember to dig it out. -- Kvetner 21:02, 20 May 2007 (UTC)
I agree, do not use "largest." To me largest infers width and length, which is an important consideration for a long span (harder to hold up eight lanes of traffic than two for a thousand foot span). It can be an important part of the bridge article to discuss how large the bridge is. For instance, the Zakim Bunker Hill Bridge is ten lanes wide, including two cantilevered outside of the cables.
Let me give the longest length a whirl. In a tabular format, these are the lengths for the three bridges in question:
Bridge Longest Span Total Length of
Cable Supported Spans		 Total Length of Bridge
(includes all approach spans)
Sunshine Skyway Bridge 367 m 695 m 8851 m
Longest
Millau Viaduct 342 m 2460 m
Longest		 2460 m
Rio-Antirio bridge 560 m 2,258 m 2,880 m
So again I say it is most important to list cable-stayed bridge in order of their longest span, but it is also worthwhile to discuss in the article things like the total length, height, etc. - SCgatorFan 02:23, 21 May 2007 (UTC)
I think the second column in that table, the longest continuous length of cable-supported spans, is actually quite important - I had a look through the Virlogeux paper and it's clear that the design of multiple cable-stayed spans presents some quite distinct challenges. When I get time I'll see if I can add some relevant information to the bridge-specific articles. -- Kvetner 08:14, 21 May 2007 (UTC)
Exactly. I completely agree with you. The total length of cable supported spans is quite important and should be discussed prominently in the article. Bridges like Millau and Rio-Antirio with so many main spans are way better than the Sunshine Skyway.
So let me ask you this question. If all other things are equal, which of the following cable-stayed bridges would be harder to build (require greater engineering talent, be more impressive, rank higher on your list, have more risk involved in the construction, be harder to maintain, etc.): Bridge A with spans of 200 m, 4 x 400, and 200 m (2,000 m total); or Bridge B with spans of 300 m, 2 x 700 m, and 300 m (2,000 m total)? - SCgatorFan 00:09, 22 May 2007 (UTC)
I'm not a cable-stayed bridge expert (I've only designed and had built one), but of those two, I would say Bridge B - the longer main spans will be more complex to design because of concerns over wind and seismic loading during construction, while the two cantilevers haven't yet connected at the middle of the main spans. Other issues, such as non-linear effects and cable vibration, may also be greater for larger spans.
However, if the two bridges were Bridge C with spans of 150 m, 3 x 250 m, and 150 m (1,050 m total); and Bridge D with spans of 250 m, 550 m and 250 m (1,050 m total); the answer would be different. In this case Bridge C is more complex to design, because it has more than 3 spans. A 2-span or 3-span cable-stay bridge will always have the loads in the main spans anchored back to near the end abutments via stays in the back spans. For more spans, this isn't the case, and the bridge structure is less stiff overall.
This complicates the whole design considerably, and you can see the result at Ting Kau Bridge, where additional 'cross-bracing' stays are used to stabilise the towers; Millau Viaduct, where twin-legged towers were used; or General Rafael Urdaneta Bridge, where very stiff multi-legged frame towers were adopted. A similar problem for a suspension bridge is found on San Francisco-Oakland Bay Bridge where additional anchorage piers are required after every set of three suspension spans - this is another solution which can be used on cable-stays as well.
I guess there's scope to add some or all of the above to the cable-stayed bridge and suspension bridge articles! -- Kvetner 08:06, 22 May 2007 (UTC)
The cable and suspension bridge lists probably need a sublist for bridges with multiple main spans. This list can be in order of total cable-supported length. Bridges with multiple main spans could appear on both lists.
Since the following statement appears on both list pages, something needs to be done there:
The length of the main span is the most common way to rank (cable-stayed/suspension) bridges. If one bridge has a longer span than another it does not mean that the bridge is the longer from shore to shore or from anchorage to anchorage. However, the size of the main span does often correlate with the height of the towers and the engineering complexity involved in designing and constructing the bridge.
There should probably need to be quidelines written for how to claim anything other than the longest main span. For instance, the Sunshine Skyway Bridge's claim could be read to be either the longest bridge (abutment to abutment, including approach spans) with a cable stayed main span OR the longest cable-stayed bridge main span copnstructed of a concrete cross section (no steel girders). Which way would you read it?
BTW, the San Francisco-Oakland Bay Bridge article says that the anchorage in the middle was put there to make the west span act like two separate suspension bridges. So it probably doesn't need anything added. - SCgatorFan 21:47, 22 May 2007 (UTC)

I've edited Cable-stayed bridge, Sunshine Skyway Bridge and List of largest cable-stayed bridges to address the above. I haven't attempted a list of largest multi-span cable-stay bridges, this would take a bit more time! -- Kvetner 12:01, 23 May 2007 (UTC)

I wanted to add the info. to Rio-Antirio bridge but then I noticed an older discussion at Talk:Rio-Antirio bridge#World's Longest on identical lines as this one, that finally seems to have settled on Rio-Antirio being "longer" than Millau. This seems to be "because there are no bearings at the piers" as an anon puts it. Any comments? -- Paddu 22:02, 24 May 2007 (UTC)
I find it hard to beleive that there is no bearing at the piers. While there is may not be vertical bearing, there must be lateral (horizontal) bearing. The Alex Fraser Bridge and the Arthur Ravenel, Jr. Bridge have no vertical bearing at their towers (the maintenance travelers pass through the towers), but they have lateral bearing. - SCgatorFan 02:35, 25 May 2007 (UTC)
Okay, this complicates things a little. Paddu is correct that there is no vertical bearing at the piers (there are horizontal connections via anti-seismic dampers). This makes the Rio-Antirio bridge the longest continuous bridge deck supported only from cable-stays. I don't think this is particularly interesting, however - whether the deck hangs only from the cables or has an extra support via bearings at the towers is not really very important, at least as far as design of the deck itself goes.
However, Millau remains the longest cable-stayed bridge deck. I would suggest the Rio-Antirio Bridge article is clarified and Millau specifically mentioned there. In terms of design complexity, both are similar: the Rio-Antirio bridge has the advantage of no sliding bearings at the piers, which means the piers don't have to cater for frictional forces due to the thermal movement of the deck. As a result, the pylons are designed as rigid frames. The Millau Viaduct does have connections at the piers, which means that the piers are designed for restraint forces due to thermal movement of the deck. In this cases, the pylons and piers are both designed as flexible elements to reduce these restraint forces. -- Kvetner 08:37, 25 May 2007 (UTC)
What exactly is meant by "bearing" here (and "vertical" and "lateral" bearing)? And are we talking about the cable-stay towers or piers of the approach viaduct? (The above seems to talk about the towers whereas the Rio-Antirio talk page seemed to talk about the piers at the end of the cable-stayed portion. -- Paddu 20:35, 27 May 2007 (UTC)
A bearing is a mechanical device connecting two parts of a structure. In a conventional bridge, there are bearings below the deck, resting on the abutments and piers, carrying a mixture of vertical and horizontal loads. This is also true on cable-stayed bridges - there are quite often bearings supported on a crossbeam at the pylons - this helps reduce the length that the deck has to span between points of cable support, and therefore allows the deck to be a bit more economical. A "vertical" bearing carries vertical loads i.e. the weight of the deck and any vertical loads on it (traffic and a vertical component of wind load). A "lateral" bearing carries horizontal loads which are perpendicular to the direction of traffic (typically wind loading, but can also include the effects of seismic acceleration, and centrifugal forces if the deck is curved). For my part, when I referred to "piers" I was referring to the parts of the towers that are below deck level. The piers to the approach viaducts aren't relevant to the cable-stayed spans, and those piers will certainly have vertical bearings. Does this help? -- Kvetner 22:10, 27 May 2007 (UTC)
Piers, pylons and towers are often used interchangeably in describing cable-stayed bridges, so sometimes you just might need to ask. - SCgatorFan 01:59, 29 May 2007 (UTC)
I would think that the lateral bearing (or support) provided by the seismic dampers on the Rio-Antirio bridge also provides a point of fixity when designing for flutter (See Galloping Gertie). A true bridge deck supported only from cable-stays of the length we are speaking about would be a nightmare to test in the wind tunnel. - SCgatorFan 01:59, 29 May 2007 (UTC)

Further to the above, it is suggested in an earlier comment that Sunshine Skyway Bridge may be the longest concrete cable-stayed bridge span. In fact it's the Skarnsund Bridge in Norway, and I've amended the Skarnsund bridge article with a reference confirming this. -- Kvetner 11:42, 8 June 2007 (UTC)

Or may be the author intended it to be "the longest concrete bridge that has a cable-stayed main span" (phew! :-)). -- Paddu 22:10, 17 June 2007 (UTC)

[edit] Add a section to define bridge parts?

Should there be a section added to list and define parts of a cable-stayed bridge? A short list to start would be

  • main span,
  • side span/back span,
  • tower/pylon,
  • anchor pier (both counterweight and tension),
  • intermediate piers in the back spans,
  • stay cables (including those continuous through a saddle in the tower), and
  • anchorages.

I think this would be a helpful part of the article. - SCgatorFan 03:12, 24 May 2007 (UTC)

I think it would be best as a diagram. I'd be happy to draw up a hand sketch if someone else has the technology to turn it into a computer-drawn diagram. -- Kvetner 08:39, 25 May 2007 (UTC)

[edit] Sweet spot

"The cable-stay design is the optimum bridge for a span length between that of cantilever bridges and suspension bridges."

So, roughly, what is the range of lengths for this type of bridge?
—wwoods 02:47, 7 June 2007 (UTC)

The form is used for footbridges from spans of about 40m up to about 150m, although there will often be cheaper solutions at the bottom end of that range (trusses up to about 50m, and bowstring arches up to a bit more than that), and at the top end suspension footbridges start becoming more common.
For highway and rail bridges, they have been used at spans as low as about 75m, but start coming into their own above about 150m, where girder bridges can be very expensive. They then range up to about 1km, although there are obviously very few cable-stayed bridges with spans approaching that. It has been stated that spans up to about 1.75km are feasible (source, Rene Walther's book, p.14). -- Kvetner 11:43, 8 June 2007 (UTC)

[edit] First cable-stayed bridge

An edit on 27 June 2007 revised the history section to say that the Donzere-Mondragon (France) Bridge was the first modern cable-stayed bridge. It also added a picture. Looking at the picture, I see an extradosed bridge. The towers are short and the cables are less than 45 degrees (meaning that they impart more horizontal force than vertical support). I think that either a refernce is needed or the statement needs to be revised. Is the Donzere-Mondragon a modern cable-stayed bridge? - SCgatorFan 14:40, 30 June 2007 (UTC)

I'll do a bit of a book search when I get a moment. It isn't mentioned in Walther's book "Cable-stayed bridges", which describes the Stromsund bridge as "the first modern steel cable stayed bridge". From that, and looking at structurae, I'd guess that the Donzere-Mondragon bridge could be the first modern concrete cable stayed bridge. I don't think the cable angle is entirely relevant - one of the features of an extradosed bridge is that essentially it's a post-tensioned bridge in which the post-tensioning cables are brought above the line of the deck (hence the term "extrados", normally referring to the top surface of an arch bridge, but here the top surface of any bridge). While this might be true of Donzere-Mondragon, it's only a subset of the cable-stayed bridge type. I'll report back once I've looked through some other sources. -- Kvetner 12:01, 4 July 2007 (UTC)
I've done some brief research and updated the history section accordingly. There's lots more I could add if I get time, but that will do for now. -- Kvetner 21:36, 6 July 2007 (UTC)

[edit] First US cable-stayed bridge

Scgatorfan removed my additions about the Bluff Dale, Texas, bridge being the first US cable-stayed bridge, making reference to HAER drawing #2 to support his position. I've undone his change. Without any intent to be confrontational, if it's not cable-stayed, what is it? It's not a suspension bridge formed from or hanging from a catenary rope, cable, or chain and it's clearly not a beam, cantilever, arch, or truss bridge. While the angles of the support cables are low, it doesn't have the beam/girder deck needed to make it an extradosed bridge. That could, however, have very well have been the reason the Howe trusses were added along the top of the deck, as shown in the HAER drawings, but according to the HAER notes the bridge was in service for 9 years before that was done and the original deck design was clearly not intended to have any vertical stiffness on its own. To say that it wasn't a cable-stayed bridge in its original design and during its first 9 years of service, at least, seems to be splitting hairs. I'd welcome others' thoughts on the matter. TransporterMan 17:04, 28 August 2007 (UTC)

[edit] Fair use rationale for Image:Denver milennium bridge5.jpg

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[edit] Zhivopisny Bridge

Hello, could anyone add information about that bridge to this article? It's quite an unusual structure and the highest in Europe (since it's opened today). I'm not an engineer or an architect, so I have no idea how to describe it. There are also some good photos of it here: http://russos.livejournal.com/409954.html // vh16ru talk 17:24, 27 December 2007 (UTC)

[edit] Second Severn Crossing

I am removing this recent add to "Notable cable-stayed bridges" by 172.159.125.237 (talk · contribs):

“ Second Severn Crossing in Wales, U.K, is the longest bridge in Europe over 5,000m in length connecting England and Wales and major cities of Cardiff, Capital of Wales, Bristol and London. ”

It is not the longest bridge in Europe, nor even the longest cable-stayed span. The Severn is the longest river in the U.K., maybe there is some confusion. Anyway, if you think it is notable enough for this list, please explain. Colfer2 (talk) 05:38, 11 March 2008 (UTC)