The historic Route 66 bridge over the Rio Puerco is the longest single-span steel truss bridge in New Mexico, built to withstand the river’s violent flooding.
Where the bridge that was once part of Route 66 crosses Rio Puerco, about 20 miles west of Downtown Albuquerque, people have forded the usually dry but often flooded river for more than seven centuries — ever since people began migrating from the Chaco pueblos toward the Rio Grande.
Before the Rio Puerco Bridge
Of course, at first, they walked. After the Spanish brought horses, they rode. This was the trail Gen. Stephen Kearney took in 1846 on his way to fight the Mexican army in California. Lt. Edward Beale traveled it in 1867 with his camel brigade. He was surveying a wagon road, although it was already being used by immigrants.
When U.S. Route 66 was laid out, it followed the old wagon trail. At Rio Puerco, motorists would have had to negotiate the steep banks and sandy bottom.
When the river was flooding, they would have had no choice but to wait. Early attempts to bridge the river almost always resulted in it being washed away during the next monsoon.
Building a Better Rio Puerco Bridge
These problems were not acceptable to a nation trying to develop a transcontinental road system and encourage travel and commerce. So, Rio Puerco was spanned by a bridge needing no center pier that could be washed out.
To combat the river’s violent flooding and severe erosion, highway engineers chose a Parker through-truss bridge design.
The span is commonly known as a “camelback.” All the structural support for the roadbed is incorporated in a steel arch standing above it.
The design was a modification made by Charles Parker, a Massachusetts engineer who worked with Thomas Pratt. It was Pratt’s design Parker modified.
The Rio Puerco bridge consists of 10 panels, each with its top cord at a slightly different angle. It is the varying cord angles that make the “camelback” arch. The bridge is 250 feet in length, the longest single-span, steel truss bridge of its time in New Mexico.
It has a 25-foot-wide concrete deck with an asphalt surface. The design was a popular one in the late 1920s and early 1930s, but it was selected for Rio Puerco to withstand flooding that had washed away so many other bridges.
The U.S. government funded the bridge in 1933 as part of President Roosevelt’s effort to use emergency monies for highway construction. F.D. Shufflebarger oversaw construction.
Components were made by the Kansas City Structural Steel Company. It was completed within a year and carried traffic until Interstate 40 was built.
The Rio Puerco Bridge Today
With the Interstate, the Rio Puerco bridge became part of the frontage road but, as the bridge aged, it became apparent it would no longer be safe.
Instead of demolishing the structure, the New Mexico State Highway and Transportation Department had it listed in the National Register of Historic Places in 1997 and built a new bridge for the frontage road to the north.
You’ll find the Rio Puerco bridge nestled between I-40 and the frontage road. Cars are no longer allowed on the span, but it’s open for curious people to walk across.
Make a point of exploring the bridge and feel connected to the way we traveled a generation — or maybe two — ago.
Stand on the roadbed over the center of the river and watch The Mother Road dip and curve to the east. It disappears over the horizon from the east.
Turn 180 degrees to watch the old road climb uphill to the west where, with a slight bend to the left, it has been overtaken by the interstate and now lies beneath it.
That’s the way it is on Route 66 these days — a snippet here, a snippet there — each with its own unique story.
Follow Albuquerque.com on Social Media
