Millions of years ago, the dramatic landscape of the Columbia River Gorge was formed by two repeated geologic actions: lava from volcanic eruptions and a series of rapid inundations known as the Missoula Floods. Lava accumulated and hardened 6,000 feet thick, and periodic flood waters carved away at it, leaving behind a wide river basin flanked on the north by golden grasslands and on the south by columns of basalt pierced by waterfalls. Today, this protected land is known as the Columbia River Gorge National Scenic Area (CRGNSA).

Since the 1950s, Interstate 84 has wound along the southern bank of the Columbia River; it is an economic lifeline that brings commerce as well as travelers east and west through Oregon. Along this corridor are eight bridges that the Oregon Department of Transportation (ODOT) is replacing through its 10-year, $1.3 billion OTIA III State Bridge Delivery Program. Each bridge offers a vantage point from which to observe the beauty of the gorge and also provides a critical economic link for local communities.

For the first time, ODOT is coordinating its highway and bridge construction in the gorge to include input from all stakeholders and to address all aspects of transportation infrastructure and landscaping.

Representatives of state and federal agencies, adjacent counties, and the private companies working as consultants on the bridge program collaborated to develop design guidelines for this area. Known as the Gorge Committee Level 1 Team, this group developed the guidelines in partnership with local citizens, who participated via a series of public meetings before design and construction began. The resulting I-84 Corridor Strategy provides a framework that helps ODOT manage and improve the interstate in ways that meet public safety and transportation needs while also meeting National Scenic Area provisions.

History of bridges in the Columbia River Gorge
As long as humans have lived in Oregon and Washington, the Columbia River Gorge has been a vital transportation corridor that allowed traders and settlers to bypass the rugged Cascade Mountains and provided easier passage to all parts of the river.

When the trail along the Oregon side was paved early in the 20th century, it became the Columbia River Highway. The first planned scenic roadway in the United States, it features bridges 18 feet wide with stone façades and arches. The route provided greater access for commerce and pleasure, but because it hugged the rugged, winding cliffs that make up the south side of the gorge, it allowed no room for expansion. As the need for rapid transit increased in the 1940s and 1950s, the federal government decided that I-84 should be built at water level.

The eight new bridges on I-84 will hark back to their elegant predecessors on the Historic Columbia River Highway. ODOT is striving to remain faithful to the lofty vision for the original gorge highway, as stated by its locating engineer, John Arthur Elliott:

The ideals sought were not the usual economic features and considerations given the location of a trunk highway. Grades, curvature, distance, and even expense were sacrificed to reach some scenic vista or to develop a particularly interesting point. All the natural beauty spots were fixed as control points, and the location adjusted to include them. …The one prevailing idea in the location and construction was to make this highway a great scenic boulevard surpassing all other highways of the world.

Public involvement with a view
A series of landmark public meetings to create the design guidelines for the gorge bridges began in January 2005. The project team held open houses in the four most prominent towns along the interstate — Troutdale, Cascade Locks, Hood River, and The Dalles — to solicit initial input.

Follow-up meetings in May allowed members of the public to refine their suggestions. ODOT also held a daylong workshop in which architects and engineers helped participants turn design ideas into preliminary sketches. The discussion of design elements ranged from abutments and railings to landscaping and wildlife crossings.

Working from public feedback, the Gorge Committee created two bridge design options: a Cascadian design with a rocklike façade and a sleek, contemporary design that allows excellent sightlines for viewing the beauty of the gorge. Design teams would be able to choose the type that best fit a specific bridge site. Of primary concern was coloration because the gorge is a typical Western landscape full of shades of tan and brown.

That August, open houses in Troutdale and Hood River allowed members of local communities to review the bridge design guidelines for I-84. Participants at the August meetings were pleased and excited by the chosen designs and enthusiastic about a process that gave them a voice in how the gorge would look in the future. Later that fall, ODOT design teams met with gorge residents and stakeholders to unveil further guidelines for rockery, roadside vegetation, sightlines, right-of-way features, signage, lighting, and culverts.

In 2007, ODOT was pleased to learn that the I-84 Corridor Strategy had earned an Engineering Excellence National Recognition Award from the American Council of Engineering Companies. By then, design of the bridges was well under way; construction began in 2008.

The vision takes form
The first bridges ready to make the switch from pale-gray, nondescript highway bridges to Cascadian-style spans are located just west of Cascade Locks. The city commemorates another significant era in gorge history: the completion in the late 19th century of a set of locks and a canal that would facilitate steamboat traffic on the river, replaced in the 1930s by Bonneville Dam.

Like their predecessors on the Historic Columbia River Highway, the contemporary bridges boast facades that imitate stone. To create them, in fall 2009 contractor crews poured concrete into a plastic form incised with irregular rock shapes, similar to those in a hand-stacked wall. (These forms will be reused repeatedly on other bridges in this program.) In addition to the time required for the concrete to set up, the project team had to wait in line for popular specialty contractor Livingstone Paint, in demand all over the region for staining concrete. The deep-brown facades of these two bridges were just completed in July.

In the meantime, other design elements were receiving the I-84 Corridor Strategy treatment. A retaining wall 1,200 feet long that will support a bicycle and pedestrian path is finished in the same Cascadian rock style. Guardrails of weatherized steel, which rusts to a similar pleasing dark brown color, line the side of the road. And seven miles of cast-in-place concrete median barriers blend in nicely with the surrounding landscape, built low enough to preserve a scenic line of sight for drivers.

Works in progress
Because it is a first-of-its-kind initiative, the I-84 Corridor Strategy has been debated, refined, and modified as the guidelines have been tested in actual projects. The final version will be published this fall.

The CRGNSA is demarcated by the Deschutes River to the east and the Sandy River to the west, so it is fitting that OTIA III bridge construction will culminate with replacement of the Sandy River bridges, which constitute the gateway to the gorge. With a range of stakeholders as diverse as the 40-Mile Loop bike advocacy group, the U.S. Forest Service, and the city of Troutdale, these bridges will be the ultimate test of the design guidelines, viewed from above by drivers moving at 65 miles per hour as well as from alongside and below by inner-tubers, drift boaters, cyclists, and dog walkers.

As with the waterways and the railroad lines before them, the new bridges will maintain the gorge’s age-old mission as a safe and efficient transportation route. And in their graceful subtlety, they will reinforce its timeless beauty.

Steve Narkiewicz, P.E., is a consultant project manager for the OTIA III State Bridge Delivery Program with the Oregon Department of Transportation.