There was a round of critics who claimed that truss bridges are obsolete and cannot be used for today’s highway standards, especially because they are fracture citical, meaning if one part fails, the rest of the bridge fails. This echo was first started in response to the Minneapolis Bridge Disaster of 2007 and reinforced because of the collapse of the I-5 Skagit River Crossing. If that was really the case, then there are two questions that the critics should try and answer:
1. Why are truss bridges still being built today to serve vehicular traffic and
2. Why are bridges like this one presented here, being replicated?
The Motor Mill Bridge, located over the Turkey River on Galaxy Road southeast of Elkader in Clayton County, Iowa maybe considered one of the finest examples of how truss bridges like this can be built, let alone how bridges lost to a disaster can be replicated to almost the finest details. The two-span pin-connected Pratt through truss bridge was built in 1899 by a local contractor, A.C. Boyle, whose bridge company was located in MacGregor (along the Mississippi River south of Prarie du Chien) and who was responsible for constructing many small crossings in northeastern Iowa at the turn of the century. This bridge, which features a 7-rhombus Howe Lattice portal bracing with heel bracing served traffic for 93 years before the floodwaters knocked out the southern span in 1991. While the northern span survived the 1993 flood, it finally fell to nature’s rath in 2008. This was when the people of Motor Mill took action, and four years’ of tireless efforts paid off with a replica built late last year, which is now open to traffic. I had an opportunity to interview the people at the Mill about trials and tribulations behind rebuilding the bridge and had two people provide some details of this massive artwork that was reconstructed, literally from scratch. This article will feature a Q&A session with Tim Engelhardt while the next one will feature a summary provided by the Motor Mill Foundation:
1.What factors motivated you to embark on the bridge restoration project?
The motivation was the south span of the two span bridge was washed out in 1991. Since that time, the Clayton County Conservation Board pursued a variety of means to replace the span. The public seemed to want the bridge replaced, the county road system was fine with not replacing it but the Conservation Board felt the bridge was important to the Motor Mill Site for access. We kept running into the historical nature of the structure to prevent the replacement of the south span. At one point, we were told the only way it could happen if we built a pedestrian bridge within the remaining span. At an estimated cost of $1 million dollars, there was no way the residents of Clayton County would like spending that much money for a bridge they could not drive across.
After the flood of 2008, which washed out the remaining north span the situation changed. The bridge replacement then became a FEMA project with the “right” historical person involved. Through a variety of conversations, proven planning, completion of several other projects at the site and several people helping we were able to get the project approved to replace the north half of the structure. We had preserve the stone work on the north and south abutments and the center pier. No longer did we need to preserve the bridge structure itself.
Supplemental question: Why restore a bridge whose one span was destroyed in 1991 and the other in 2008?
The public seemed to have wanted the bridge replaced. Access to the site was 7 miles of gravel road of which the last couple of miles was a dead end. We had developed the Motor Mill Foundation, which had done a lot of work at the site with replacing roofs, flooring and having the mill open for tours on weekends. The bridge access would allow only 2 miles of gravel and better security.
2. What is the general history behind the mill and bridge?
Instead of writing this out, there is a section about the bridge on the motor mill website you may read here: http://motormill.org/
3. Who did the construction of the bridge?
VJ Engineering designed the bridge and Minnowa Construction, Harmony MN did the actual construction of the bridge.
4. How did the construction of the bridge replica influence its National Register of Historic Places listing (bridge was listed until 2008)? Did you receive this status back?
The status on the bridge structure itself was dropped as soon as the north span went underwater. The stone work is still listed along with the rest of the site. The new bridge is not part of the National Register of Historic Places. As part of a mitigation project for another FEMA project at Motor Mill, the site is being expanded on the current listing.
5. How did you gather enough funding for this project? Who was all involved?
FEMA funded part of it, we received a REAP Grant through the state of Iowa, received funding from the Iowa Great Places Grant, and a local grant through the Upper Mississippi Gaming Corporation and private donations. 90% of the funding was through grants.
Author’s note: REAP stands for Resource Enhancement and Protection and information on this can be found here.
6. Looking at the Sutliff Bridge (whose easternmost span was washed away by floods in 2008), there was a lot of criticism regarding how the bridge was restored and that it was not original. Did you receive any criticism from anyone regarding the reconstruction of the bridge?
No criticism. The public is excited to have the bridge back in place.
7. Referring to the comparison of the two bridges, in your opinion, do you think truss bridges are making their way back to the scene as a structure of choice for vehicular traffic?
My expertise is not that large. We wanted the Motor Mill Bridge to look like the historical pin connected Pratt through truss bridge.
Author’s note: This will justify a question for the larger forum to be presented after the Historic Bridge Weekend in August.
8. How has the public received this finished piece of artwork?
We have had one marriage proposal and a set of prom pictures taken on the bridge in the first 5 months of the bridge being open. I believe this speaks for itself.
Author’s note: One note is the fact that many bridge enthusiasts will be visiting the bridge in August during the Historic Bridge Weekend, specifically on Friday the 9th of August between 2:00 and 2:30pm. If interested, please contact Jason Smith at the Chronicles or just stop there at that time.
9. If one wants to see the bridge, how to get there from Elkader?
From Elkader head south on Hwy 13, turn left onto Grandview Rd. Then a left on Hazel, a left on Galaxy to the Motor Mill site. The Park is well signed from Hwy 13.
You can also find the info and GPS coordinates here.