Talk:Bridge of the Americas

Type of bridge design?
Wouldn't this bridge be more correctly identified as a Compression arch suspended-deck bridge? Or have I overlooked some technical detail(s)? -- Gyrofrog (talk) 16:21, 9 January 2006 (UTC)
 * I copied the info from somewhere else, and shoot, I didn't cite my references — sorry, but I'm learning. Anyhow, if you have better information, I guess you should change it, specially if you can add detailed reference citations.  — Johantheghost 16:27, 9 January 2006 (UTC)

Type of Bridge Design (Part Deux)
There seemed to be some agreement above that this bridge is not a cantilever bridge. However, this bridge was added to the List of longest cantilever bridges in October 2007. In June 2008, the bridge was removed and then put back on the list quickly (by different users than the one that did the list edit in 2007).

I do not consider this bridge to be a cantilever and would like to discuss it fullt here and come to a concensus.

Let's start where we can agree. It is a (1) steel-truss (2) arch bridge with a suspended deck. I think that is self evident from the photos. It is also a (3) through-truss because the deck level is at times between the top and bottom chords.

Now, to be a cantilever bridge the bridge must have connections in the main span of zero (or near zero) moment. This is the section of the main span that is always called "the suspended span". These points of zero moment are quite easy to see on the famous Forth Railway Bridge. The are at each end of the seemingly tiny suspended span that occurs within the multiple cantilever spans of that bridge. These points of zero moment are key to making the bridge be statically determinate. (See Statically indeterminate) This point was key to engineers of the pre-computer era being able to calculate the structural design. (The use of a cantilever to extend a span was patented in 1866 by a man named Heinrich Gerber. In Europe they will still sometimes refer to a cantilever as a "Gerber girder" or a "Gerber Truss".)

Lacking points of zero moment, this bridge is (4) "multi-span continuous". From the photos I find on-line, I think the bridge could be as much as seven-span continuous. I cannot tell where there are expansion joints based on the photos.

I would not classify the bridge as a "compression arch". It is true that an arch will create horizontal thrust, however I do not see how the slender piers at each end of the truss could be designed to handle thrust or compression forces. Instead, I would think that the thrust is handled by the nature of the continuous truss.

Does someone have evidence (verifiable reference) that this is a cantilever? - SCgatorFan (talk) 03:32, 20 June 2008 (UTC)


 * I added the bridge to the List of longest cantilever bridges based on this list. VerruckteDan (talk) 15:22, 21 June 2008 (UTC)


 * That list contains two entries for this bridge. One under steel arch (850 feet) and one under cantilever truss (1,128 feet). This expains it to me. The suspended span for the bridge is an 850-foot tied arch. I can now see the zero moment points at each end of the tied arch.


 * The bridge is a steel-truss cantilever with a tied-arch suspended span.


 * Thanks very much. - SCgatorFan (talk) 21:00, 21 June 2008 (UTC)


 * Glad I could help. VerruckteDan (talk) 21:47, 21 June 2008 (UTC)

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bridge raising ?
are here any plans to raise bridge clearance up to 75/80 m ? since current clearance was problems for some ships even before new set of locks. — Preceding unsigned comment added by 2A00:1028:9198:E50E:3D1E:98D9:69B4:81BD (talk) 07:01, 5 June 2018 (UTC)