Last updated: June 6, 2022
Of the great number of bridges built on Route 66, Bridge #18 at Rock Creek is one of the better examples of the remaining steel-truss bridges in Oklahoma. Truss bridges were developed in the mid-1800s and used extensively until World War II, when technology changed and more standardized concrete designs were developed.
In terms of lineage, the ancestor of the steel-truss bridge is the beam bridge, usually built of wood and limited in the amount of weight it could support. As a result, early roads generally followed old trails where rivers and creeks were shallow. Even bridges that were quite long were located at shallow crossings.
One of the oldest types of modern bridges, truss bridges were altogether something new. Bridge #18 at Rock Creek is composed of connected elements, in this case steel beams, which stressed by tension and compression (or sometimes both) in response to dynamic and heavier loads. Because of truss bridges, deeper water could be safely crossed. Roadways no longer had to meander from one low-water crossing to another. Instead they could be built along the shortest route. Bridge #18 is a Parker through truss bridge. Its ancestor is the beam bridge, while its descendants are today’s cantilever, truss-arch, and lattice bridges. Unusual for a steel truss bridge, #18 has brick decking.
Bridge #18 is an illustration of the bridges of its era. Route 66 travelers who crossed Rock Creek near Sapulpa during the late 1920s would have thought the bridge the most dynamic design of its time, and it was. Constructed in 1924, #18 served as part of the old Ozark Trail, one of the few marked U. S. roads at the time. It became part of Route 66 in 1926. Just over a decade later the State’s entire section of Route 66 was paved. The bridge served Route 66 until the construction of a new alignment in 1952. The bridge was listed in the National Register of Historic Places in 1995.
Sapulpa itself, a town of about 20,000, has some notoriety unrelated to its historic bridge. Chief Sapulpa, the area’s first permanent settler, was a Creek Indian. In 1850 (at just about the same time engineers were designing the first truss bridges), he established a trading post near the meeting of the Polecat and Rock Creeks. Sapulpa is the home of Frankoma Pottery, established in 1933 and sometimes making appearances on Antiques Road Show.
Bridge #18 at Rock Creek is currently closed to vehicular traffic, but is worth a visit to admire its historical legacy.
See the Bridge #18 at Rock Creek National Register nomination form.