Oneonta Gorge Creek Bridge
Spanning Oneonta Creek, Multnomah County, Oregon, on the old alignment of the Historic Columbia River Highway, beginning at milepost 34.3.
View Oneonta Gorge Creek Bridge in a larger map
Date of Construction
1914; bypassed 1948
K. P. Biliner, designing engineer, Oregon State Highway Department
The Construction Company, Portland
Oregon Department of Transportation
Pedestrian traffic and vehicular parking (Note: bridge no longer open for vehicular parking)
One of two nearly identical reinforced concrete girder trestles on the Historic Columbia River Highway and one of four extant structures on the route that have a distinctive cap and arch concrete guard rail system.
Oneonta Gorge Creek Bridge
The Historic Columbia River Highway’s alignment from Crown Point, milepost 23.9, to Horsetail Falls Bridge, milepost 34.6, takes the highway along one of the largest concentrations of high waterfalls in North America. Near its eastern end lies Oneonta Creek and Gorge. The name “Oneonta,” according to Oregon Geographic Names, originates in Oneonta, New York, and means “place of peace.” The Oregon Steam Navigation Company ran a sidewheeler named Oneonta on the Columbia, above and below its cascades, in the 1860s and 1870s. Oneonta Creek and Gorge probably were named sometime after the boat began sailing on the river.
In 1914, the Multnomah County Road Department and Samuel Lancaster sought to align the route so that it brought travelers to the mouth of Oneonta Gorge, a canyon so narrow that its basalt walls almost touch as they rise two hundred above the creek. Motorists could only reach the gorge’s spectacular falls, some 900′ back from the road, by walking upstream in the waters of the creek. The county easily could build a bridge to span the stream, but to carry the highway alignment past a nearby 200′ bluff, a continuation of the gorge, proved difficult. The Oregon-Washington Railroad and Navigation Company (OWRN) had laid out its route along the Columbia River’s south shore in the 1880s. Much of it followed the old Troutdale to The Dalles road begun in the 1870s. The OWRN•s right-of-way crossed Oneonta Gorge Creek, then passed through a narrow opening between the river and the bluff before continuing east. With the close proximity of the river and the cliff, there was no additional space to permit carrying the HCRH around the outcropping. Determined to include Oneonta Gorge and Horsetail Falls as two of the HCRH’s natural beauty spots, Lancaster resolved this dilemma by having a tunnel bored through the bluff.
During the tunnel’s construction, K. P. Billner, designing engineer for the Oregon State Highway Department, created plans for a bridge over Oneonta Gorge Creek for the Multnomah County Road Department. It was an 80′-0″ reinforced-concrete deck girder trestle and was similar in design to the Horsetail Falls Bridge, one-third of a mile to the east on the Historic Columbia River Highway.
Design and Description
The Oneonta Gorge Creek Bridge is a four-span 80′-0″ reinforced-concrete deck girder trestle. It is 24′-0″ wide and has a roadway measuring 22′-0″ curb-to-curb. The curb and guardrail form an integral unit, cantilevered out from the girder. The curb and square endposts have bushhammered inset panels, and the railing takes the form of 12″-wide slender concrete plaster aches, spaced two per span, with beveled rail caps, and interrupted by 12″-square chamfered and capped posts. Reinforcing wire was used in the rail caps, while metal “hyrib” lath was used in the plaster arches. This design is common on the Historic Columbia River Highway, also found on the West and East Multnomah Falls Viaducts, and Horsetail Falls Bridge. A short viaduct that existed west of Vista House and Crown Point Viaduct also had a similar railing.
Difficulty in finding firm pier foundations in Oneonta Gorge Creek’s wide, flat, and gravelly stream caused K. P. Billner to design a structure with a series of small piers, or a “pile trestle,” as he labeled it. Five sets of piling were sunk 15′ to 20′ below the streambed to bedrock with a small, 300 to 400 pound horse-powered hammer. The many small piers dispersed the bridge’s dead and live loads without a heavy concentration at just a few places. The piling was cut off below the streambed’s surface and the footings for the reinforced-concrete trestle piers were placed on top of them. As added precaution against a bridge failure from the force of Oneonta Gorge Creek’s currents, which occasionally brought logs with them during spring floods, Billner decided to place concrete ties in the main channel. Under the outer spans, he had the stream bank riprapped at a 1%’:!’ slope for added protection. Finally, Billner included in his design a pedestrian staircase, leading from the bridge’s southwest corner to the streambed for motorists’ ease in reaching the streambed for their treks to see the falls.
Multnomah County contracted with The Construction Company of Portland on March 12, 1914 to construct the Oneonta Gorge Creek Bridge. It completed the structure by October 1, 1914 at a cost of $2,498.36, and used 88 cubic yards of Class A (1:2:4) concrete.
Repair and Maintenance
The Oneonta Gorge Creek Bridge served the Historic Columbia River Highway until 1948, when the Oregon State Highway Department closed Oneonta Tunnel because of rockfall hazards- The Union Pacific Railroad, the OWRN’s successor, had worried for years about the tunnel collapsing onto its right-of-way and closing its main line. In the 1940s it utilized the opportunity to move its main line near Oneonta Gorge Creek to the north on fill provided by dredging the Columbia. This permitted the highway department to reroute the HCRH around the bluff at Oneonta, thus closing the tunnel. The Oregon State Highway Department’s bridge designers, under the direction of Glenn S. Paxson, state bridge engineer, replaced the old bridge with a 48′-0″ reinforced-concrete deck girder span, placed on the old railroad bridge’s abutments. In 1948, the tunnel was mothballed and the old bridge and roadway approaching from the west became an enlarged tourist parking lot or wayside.
At present, the old Oneonta Gorge Creek Bridge receives little maintenance because it is no longer on the highway. In the early 1990s, an Oregon Department of Transportation mason recast the concrete plaster outer guardrail on the West and East Multnomah Falls viaducts and on the Horsetail Falls Bridge as part of a long-term rehabilitation program for historic road resources along the HCRH. The Oneonta Gorge Creek Bridge’s railings, however, remain untouched and continue to deteriorate. The mason, however, has rebuilt the crumbling staircase that leads from the bridge to the streambed because Oneonta Gorge is still a destination for many HCRH tourists.
Excerpted from Historic American Engineering Record, Oneonta Gorge Creek Bridge, HAER OR-36-K.
Historian: Robert W. Hadlow, Phd., September 1995.
Transmitted by: Lisa M. Pfueller, September, 1996.