Photo taken by Lynn Graesing//Provided by Linn Grove Iowa.org
BH Photo #273581
The court cases mentioned in the description were a major spring board in the career of Conde McCullough, famed Oregon bridge engineer. McCullough was the lead bridge engineer for the Iowa State Highway Commission at the time of many of these court cases and served as an expert witness assisting in breaking Lutenís hold on the concrete bridge market. McCullough also worked for James Marsh for a short period prior to becoming an engineer with the ISHC, which may have also been a factor in taking on the Luten lawsuits.
I find it amusing that this subject should come up, since I was just in the process of seeing if I could find any remaining McCullough designed bridges in Iowa.
Based on the information from the historic bridge inventory, it appears that this bridge is not a true "Luten arch" because usually that is reserved for bridges that Luten himself was associated with. However, it would appear to be a bridge that uses a reinforcing that is at least somewhat similar to Luten's design. I honestly believe these patent-happy engineers, (Joseph Strauss is another good example) purposely came up with as many patents as they could think of and used as broad language as they could in the patent text so that they could sue the maximum number of people possible. It was a business strategy, a way to defeat and scare away the competition.
Yep--my error. My description was a Melan, not Luten. This bridge must have used the Luten type of reinforcing--not the internal structure of a Melan--based on the assumption that Luten thought he should get credit for the design.
Deck arch bridges which are essentially a steel arch encased in concrete are generally called Melan arches. The Luten system used reinforcing rods, according to Luten's own literature.
It sounds like it's close enough copy of a Luten to annoy Luten. I think technically the Luten system uses internal steel arches to carry the load and encases them in concrete. Without seeing the internals it can't be verified but closed spandrel, subtype Luten, seems about right.