Mystery Bridges 9 and 10: The bridges of Oregon

The state of Oregon has a lot to offer: Lots of hills and mountains covered with luscious green pine trees and other forms of flora, all lined up along the Snake, Wilamette and Columbia Rivers and its numerous tributaries. And of course, with as many historic bridges as the states of Indiana, Ohio and Iowa. The state has a wide variety of historic bridges to choose from, regardless of bridge type, builder, age and especially, history. This includes the likes of the St. John’s Bridge in Portland, built in 1931 and spans the Wilamette River. Portland, the state’s largest city, has as many historic bridges as the number of bridges total in the Twin Cities (Minneapolis-St. Paul).   There are the bridges that carry the famous coastal highway US 101, such as the Astoria-Megler Bridge over the Columbia River in Astoria and the Yaquina Bay Bridge in Newport.
It is also not a surprise that with as many bridges (both built prior to and after 1945) as the state has, that one needs to document them to find out more about their historic backgrounds and determine their significance to the state’s history. The Oregon Department of Transportation (DOT) conducted their bridge inventory and research in the 1980s and has started renewing its bridge inventory  recently, finding some historic bridges that have some holes to fill in their historic background. This is where Rebecca Burrows of Oregon DOT needs your help. There are two bridges that she brought up to my attention while I was away on vacation. Both of them have records claiming that they were built in the 1950s, yet judging by their aesthetic appearance, they were most likely relocated to their present spots. A summary of both are presented below, each accompanied with photos taken by Michael Goff, also from Oregon DOT.
Bridge 9:
Name: Deer Creek Bridge
Location: Deer Creek carrying Oregon Hwy. 82 in Wallowa County
Bridge type: Polygonal Warren pony truss with riveted connections but alternating vertical beams resembling a panel with an A-frame
Built (or relocated): 1964
Length: 112 feet

One can discuss about this bridge as if determining whether the glass is half full or half empty. On the one hand, it is possible that truss bridges like this one were built during this time as steel was still plentiful and counties found ways to construct bridges that were affordable and appealing to the scenery surrounding it. Some examples of such bridges include:  a pair of bridges over the Arkansas River in Chaffee County, Colorado, built in the early 1990s. However it is possible that the bridge was relocated to this site from another part of the state because such truss designs were becoming rare, and most standardized bridge designs built after 1930 required vertical beams. Recent findings (including a plaque of the people involved in the construction of the bridge appear that the bridge was built between 1905 and 1925.  In either case, the bridge is eligible for the National Register of Historic Places because of its design. However, more information on the bridge’s history- in particular determining whether the bridge was relocated here or not- is needed in ensure that the truss bridge is not converted into a pile of scrap metal, as the bridge is up for replacement at the time of this posting.


Photo taken by Michael Goff, used with permission
Photo taken by Michael Goff, used with permission

Bridge 10:
Name: Cobleigh Road Bridge
Location: Big Butte Creek carrying Cobleigh Road near Eagle Point in Jackson County
Bridge type: Parker through truss bridge with riveted connections and  3-rhombus Howe lattice portal bracing with sub-divided heel bracing
Built (or relocated): 1954
Length: 200 feet (main span); 300 feet (total length)
Unlike the previous bridge, it is very obvious that this through truss bridge was relocated here for two reasons: 1. With a width of 16 feet, it would fall short of the requirements of having a bridge with a width of at least 28 feet, as the states introduced these requirements in the 1950s. And 2. The portal bracing would fail to meet the minimum vertical clearance requirements that were being enforced at that time, which was at least 15 feet high. In fact, beginning in the 1950s, highway through truss bridges with low vertical clearance and whose portal bracing had knee bracing were retrofitted to ensure that the vertical clearance requirements were met. This included replacing the portal bracing with those that are a third as deep as the original and cutting off the heel bracing. None of this was done on this bridge. Judging by the portal bracing and the riveted connections, it appears that the bridge was built between 1915 and 1925,  at the time when standardized truss bridges with riveted connections were introduced, making pinned connected truss bridges obsolete. What makes the bridge look younger is the recent paint job that was done on the bridge, making it look like it was built in the late 1930s.  This leads to the question of where this bridge originated from. While newspaper articles may help solve the mystery, people closest to the bridge are perhaps the most important source, for many of them may still be alive to explain the story of the bridge.


Photo taken by Michael Goff, used with permission
Detail view of the riveted connections. Photo taken by Michael Goff, used with permission
Close-up of the portal bracing. Photo taken by Michael Goff, used with permission
Photo taken by Michael Goff, used with permission

Those with information on the two bridges should contact Rebecca Burrow and/or Michael Goff, who will be all ears with regards to any stories and articles that you have. You can also contact Jason Smith at the Chronicles, who will update you on the status of the bridges once the mystery of these bridges is solved. The contact details are below:

Rebecca Burrow:

Michael Goff:

The Bridgehunter’s Chronicles:

The Bridgehunter’s Chronicles brings people and history together, bridging the past and the future by providing people in the present with information on historic bridges in the US, Europe and elsewhere. It is available through, and now through facebook, twitter, LinkedIn and flickr.