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Key Facts |
Bridge Name | Type | Road | Location | City | Crossing |
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Iroquois County Highway 9 Bridge |
Arch (Steel) |
CR-9 |
Iroquois County, IL |
Rural |
Spring Creek Branch |
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Technical Facts |
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Construction Date |
Structure Length | Roadway Width |
| 1904 | 163 Feet | 17.4 Feet |
This bridge is a perfect example of what makes historic bridges so fascinating. Not only are historic bridges interesting because they feature old methods of construction and have stood the test of time, they also usually beat modern bridges in terms of unusual design and aesthetic appeal. Modern bridges generally come in two forms. A slab of concrete with no aesthetic design, or a slab of concrete with some bricks, light posts, or other elements added to try to make it look nice. In contrast, bridges from the past do require decorations to be made special (although decorations were sometimes added) because the design of the bridge itself is aesthetic. This bridge does not feature any "decorations" although the unique shape of its trussed arch make it among the most beautiful of bridges. In other words, the beauty of the bridge is in the superstructure design, not in any decorations placed upon the superstructure.
The superstructure of this bridge is anything but usual. I thought my eyes were playing tricks on me when I first looked at it. The center of the arch angles downward, giving the bridge a spider-like appearance, and making it look like one of those bridges which shouldn't even be standing. Another feature that makes the bridge look weird is how the arch gets thinner towards the center of the bridge. It is these features that makes the bridge so unusual (although steel arch bridges anywhere are uncommon on relatively small crossings such as this one). The arch of the bridge passes below the deck and is planted in the ground in front of stone abutments that may be from a previous bridge. Only the deck stringers are seated on these stone abutments. There is no bottom chord on this bridge, which sets it aside from other types of arch bridges such as the tied arch. Another interesting feature on this bridge is the sway bracing, which is latticed and features an attractive arch to it. The trussed arches follow a lattice design as well, and essentially act as subdivided double-intersection Warren trusses. The connections on this truss work are riveted. Field bolts can be found on the various sections of the bridge where they were attached.
As unusual as this bridge is, there is another bridge, in nearby Indiana's Porter County that is very similar to this bridge, although it lacks the dip in the center of the arch. It is Dunn's Bridge, and it has been restored in its original location. I also have below a postcard and old photo of the bridge below. Thanks to James Cooper and James Stewart for helping me think up some ideas on the origins and construction of this bridge as discussed below.
This bridge is only seven panels in length rather than eight as in Iroquois County's example. According to James Cooper's Iron Monuments book, which documents Indiana's historic bridges, there have been rumors that the Dunn's Bridge's trussed arch came from the 1893 World Columbian Exposition Ferris Wheel. This claim is not well backed up, especially considering that the arches are not concentric. Some have also claimed the bridge came from a 1904 Indiana Building at the St. Louis World Fair. This however does not seem as likely. Rather, the bridge may have come from some other 1893 World Columbian Exposition structure. There were other buildings besides the Ferris Wheel in the 1893 Columbian Exposition from which the trusses of this arch bridge could have originated from. An identification of the builder remains a mystery, although the names P.E. Lane and a "Chicago Bridge Company" have come up as possible builder. P.E. Lane operated a Lane Bridge and Iron Works company, but it is possible he has some sort of relationship with the Chicago Bridge Company as well. These are all speculations, but they are the best ideas that have surfaced so far. Thanks to James Stewart and James Cooper for doing some research and investigating to turn up these ideas.
