The Chinook Entrance Arch has served a dual purpose at the northeastern entrance to Mount Rainier National Park for nearly eight decades, but its useful life as both a rustic entrance portal and an overpass for hikers and pedestrians had come to an end by 2011. Now, thanks to work by skilled park crews, a nearly identical replacement is back in service.
As the accompanying photo shows, the term "Arch" may seem to be a bit of a misnomer, but the rustic structure does span State Route 410, now known as the Mather Memorial Parkway. Originally built by the Civilian Conservation Corps in 1936, the Arch now allows hikers and horseback riders using the Pacific Crest Trail to cross the highway safely. It also doubles as a classic "entrance portal" for this western national park.
After Eighty Years of Use, Time for a Replacement
The climate of the Pacific Northwest mountains puts plenty of wear and tear on any man-made facilities, especially at an elevation of over 5,400 feet, and after nearly eighty years of use, the Arch had deteriorated to the point where replacement was essential. This was a classic, one-of-a-kind structure, but park crews made excellent use of "recycled" materials and their own expertise to fashion a new bridge that is nearly a clone of the original.
Mount Rainier includes quite a few log structures, so park crew members already had plenty of experience in repairs using rustic materials. Even so, this project was on a much larger scale than most of their work.
Park Historic Architect Sueann Brown narrates a short, park-made video about the project, which was spread over a two-year period. According to Brown, "This clearly is on a much more massive scale than just replacing a few logs here and there in a back country cabin, but you know since they’ve been doing that for years they’re not only skilled, but they’re really good about just taking on new challenges."
"And, so, to do something like this [would] probably scare the heck out of a lot of people, you know, replacing these logs that span this entire roadway, getting everything to fit just exactly right to match the historic configuration," Brown continued. "They welcome those kind of challenges and they figure out how to get it done."
"Recycling" Stones and Logs
The existing stones from the original Arch were carefully removed and reused in exactly the same spots in the new structure, but what about the massive logs?
Barry McMongle, Lead Carpenter & Log Builder for the park explained: "It’s a timber structure--hundred percent timber structure--western red cedar, old growth. We were able to find downed timber to replace it almost exactly in-kind." Pointing to a pair of massive timbers, he noted, "This log is about fifteen thousand pounds, that log is about twelve thousand pounds, so they’re pretty heavy."
"What we did was we took out the logs one season, brought the original logs down to Kautz Creek so that we could work on the logs in the off-season, when this area was closed off," McMongle continued. "They brought the old log down there so they could use that as a guide for reconfiguring all the logs, and then the following season bring them back up and set them back into place."
The final result is both a safe and functional bridge and a classic park entrance portal, right down to the hand-chiseling of the lettering. Spreading the job out to allow part of the work to be completed during the winter season and utilizing park crews for the project provided an efficient—and appropriate—solution for the replacement of this historic structure.
I believe the CCC crews from an earlier generation would be pleased with the result...and park officials expect to get another eighty years of life out of the new Arch.
You can view the short video of the project at the link below: