Somewhat like the portal bracing and truss bridge discussions that was bounced around here a while back, there seems to be some grey area. But on HistoricBridges.org I reserve the idea of a column for those patented built-up beams which should also have unusually shaped parts. There actually were many different designs of columns patented during this period. Simply go to Google patent search and type in wrought iron column and look at the results. The King Bridge Company top chords are really simple in design, with riveted plate and such, and as a result I wouldn't call them columns. Anyway, thats my two cents worth on it.
Thanks for that link, it was very informative. Having lived in Decorah briefly, I al glad to see that the bridges of Winneshiek County, IA have been documented by your website.
The Column discussions on this forum have been interesting. To add a little more information, I have observed at least four distinctive bowstring top chord designs in Kansas.
1. The Keystone Columns used on this bridge as well as on the nearby Salt Creek Bowstring Bridge also in Cloud Co.
2. The "Phoenix Like" columns on the Independence Bowstring Bridge - see link in previous comment.
3. The square, built-up members associated nationwide with the King Bridge Company:
4. A similar design used by the Buckeye Bridge Works:
All of these top chords, regardless of design, fabricator, or builder are examples of built-up members. It would not be a stretch for a fabricator to observe a King Bridge Co. or Buckeye Bridge Works design and create a larger built-up member suitable for a large through truss. Where should we pontists draw the line between columns and the newer, more standardized built up members commonly used on truss bridges?
From what I have observed, WIBC used Keystone columns and Phoenix Columns in its trusses. I have also been hearing rumors of a third type of column and I need to do some investigation in that regard. As for patents and history of WIBC bowstring, I brought together some of the more relevant documentation (HAER excerpts and the patent) to a single page here: http://www.historicbridges.org/iowa/freeport/index.php
The columns on the Independence bridge don't appear to have the flat surface on each of the 4 sections that you see on most other WIBC bowstrings. I know they patented their tubular design, but without digging am not sure of the year. If the date of 1871 on the Independence span is correct, it might predate the patent and be an earlier design.
Thanks for the feedback. I am glad that you mentioned the Wrought Iron Bridge Co. because I know of another WIBC Bowstring that appears to me to feature a different type of column:
I don't know if those are Phoenix Columns or not, but I have been trying to identify them. The photos were taken during my early bridgehunting years so they are not the best. Columns are a rare find, so I have not gotten too familiar with them.
You are right, the inventory is wrong. The columns are indeed Keystone style columns and are not fabricated by the Phoenix Bridge Company. The bridge itself was built by the Wrought Iron Bridge Company.
There is a Wrought iron bridge company bowstring in Ohio that has Phoenix columns, but to my knowledge its the only one with them.
Perhaps one of my fellow pontists is a better authority on Keystone and Phoenix columns that myself. I have always thought that the top chords on this bridge resembled Keystone columns.
However, according to the Kansas State Historical Society, this bridge was built in 1876 by the Phoenix Bridge Co. http://khri.kansasgis.org/index.cfm?tab=details&in=029-0000-...
It would defy intuition that the Phoenix Bridge Co. would use columns fabricated by a competitor. Thus, I suspect that I have mis-identified the top chords. Any insight concerning these columns would be welcome.