C.B. McCullough’s legacy of bridges still unites & adorns the Oregon Coast
written and photographed by Daniel O’Neil illustration by Lori LaBissoniere O’Neil
“Jeweled clasps in a wonderful string of matched pearls,” C.B. McCullough once described his bridges, the pearls being the headlands, beaches, mountains, state parks and waysides along the Oregon Coast that he helped connect.
McCullough accomplished a lot in Oregon. He managed the state’s bridge program from 1919 to 1937, designing and overseeing the construction of hundreds of bridges across the state, including more than 30 arched spans. McCullough earned a law degree from Willamette University, published books and articles on his expertise, and received an honorary doctor of engineering degree from Oregon State College (now University).
Along the Oregon Coast, McCullough left a legacy that links towns and natural settings. “His bridges make a statement for themselves, but they also complement the landscape,” said Oregon Department of Transportation senior historian Robert Hadlow, author of Elegant Arches, Soaring Spans, a McCullough biography.
The aesthetics of the bridge mattered to McCullough, who once wrote, “From the dawn of civilization up to the present, engineers have been busily engaged in ruining this fair earth and taking all the romance out of it.” Art Deco and streamline moderne combine with classical forms to define McCullough’s bridges. Ornamental pylons and spires, Gothic arches, and, as McCullough put it, “the quiet, simple dignity” of the great arches, all point to his signature.
McCullough’s coastal bridges have served multiple purposes. As Hadlow writes, they “helped transform coastal fishing villages into tourist destinations that increased tax revenues and strengthened local economies.” They still provide safe, reliable passage across creeks, rivers, and bays. But they also offer a sense of rhythm, grace, and harmony to their coastal environment, helping to create what Hadlow calls a “dynamic experience” for travelers on Highway 101.
Drivers and passengers cannot take McCullough’s bridges for granted. The structures feel resolute and they please the eye. “His engineering was a form of art,” said Bob Grubbs, ODOT southwest region lead bridge engineer. “We’re just engineers. He was an artist who was also an engineer.”
Conde Balcom McCullough was born in 1887 in what is now South Dakota. His family soon relocated to Iowa, where McCullough would eventually pursue his studies in civil engineering at Iowa State College. After graduating in 1910 and working for the Iowa State Highway Commission, McCullough accepted a teaching job at Oregon Agricultural College (now Oregon State University) in 1916. With his wife and 2-year-old son, he moved to Corvallis.
For the next three years he taught structural engineering. Then, in 1919, the Oregon State Highway Commission offered McCullough the post of state bridge engineer. It was an exciting time to wear that hat, especially in a state like Oregon where citizens enthusiastically supported a system of road and highway development as the automobile began to transform society. By 1920, Oregon had the nation’s first gas tax to help fund highway expansion, which included bridges.
McCullough brought his graduating class of engineers to Salem, the first of many he would recruit from OSU over the next decade and a half. After beginning his Oregon bridge-building legacy with a beautiful arch at Rock Creek east of Grants Pass in 1919, McCullough and team set off to span rivers, creeks, and chasms across the state.
McCullough’s coastal bridges started off simple. The Old Youngs Bay Bridge in Astoria, built in 1921, was McCullough’s first along what became the Oregon Coast Highway. Already he was applying the emergent Art Deco style to his work, as seen in the concrete and wood pylons at each end. A double-leaf bascule drawspan, the bridge still accommodates riverine passage. But its unusually narrow deck belongs to the formative era for highway standards, when engineers addressed issues like how wide to make a lane.
Astoria’s other McCullough bridge, across the Lewis and Clark River, dates from 1924, a time when Portland and other inland towns demanded easier access to the state’s beaches. The bridge demonstrates some of McCullough’s characteristic functional elegance in its drawspan, which still works. It is Oregon’s only remaining single-leaf highway bascule drawbridge.
It would take another decade to link Astoria to Brookings with an uninterrupted roadway, but progress was made in 1927 at Depoe Bay and two miles south at Rocky Creek. Here McCullough applied his preferred method and materials, the reinforced-concrete arch, in which the concrete contains a steel skeleton for added strength. “Those two deck arches are typical McCullough with classical architectural details in the railings and on the arch ribs,” Hadlow said. “But each one’s unique, and that makes each one special.”
Reinforced concrete offered McCullough several advantages. For one, concrete resists salt air far better than exposed steel. Just as importantly, reinforced concrete allows for plasticity in design. Wooden falseworks were molded to accommodate the forms designed by McCullough and his team, then filled with concrete and reinforcing steel.
In the coming years, McCullough would expand the boundaries of reinforced-concrete arch span bridges. As a principled engineer, he designed bridges according to environmental factors like soil type, stream attributes, and the surrounding landscape aesthetics. “We call it context-sensitive design,” said Christopher Higgins, the Cecil and Sally Drinkward Professor of Structural Engineering at OSU. “McCullough put the right bridge in the right spot. Each serves a function and has a form that fits the space they’re in.”
McCullough took pride in his work’s dual nature. The art and the engineering were inseparable. “In Oregon our engineers have been trained to go to the stream, build a bridge for utility and economy, and at the same time design it so it will blend with the terrain,” he wrote.
By 1930, McCullough was finalizing designs for a bridge type new to the United States, the reinforced-concrete tied arch span. This design works like an archery bow with the bridge’s deck, the bowstring, in tension. True arch bridges rely on solid rock abutments at both ends to keep the arch in compression. The reinforced-concrete tied arch proved self-sustaining, meaning it didn’t require natural geologic strongholds: the bridge contains its own thrust. It could be placed across streams with sandy banks, like the Wilson River in Tillamook.
McCullough’s reinforced-concrete tied arch also resolved the issue of high floodwaters on rivers like the Wilson, a situation that made a standard beam, or girder, bridge impossible. And it provided better resistance to rust than a steel truss bridge in the salty maritime air. The Wilson River Bridge opened in June 1931, the first of its kind in the West. Its same 120-foot arch design was deployed later that year south of Yachats at Tenmile Creek and Big Creek, two sites with conditions similar to the Wilson River. Later McCullough bridges also incorporated this bowstring design.
“It’s a relatively small bridge in a rural setting,” Grubbs said about the Big Creek Bridge. “In today’s world, if we were to build it you wouldn’t even know you were going over a bridge. But even on the little bridges that could easily be ignored and the detail not given, he added his artistry. It shows the love he had not just for bridges but also for leaving a signature, a legacy, in the world.”
Before employing innovation with the tied arch, McCullough had embarked on a much larger and more complex crossing. Plans for the Rogue River Bridge at Gold Beach began in early 1929, and the bridge opened on Christmas Eve, 1931. Until then, a ferry had serviced the mouth of the Rogue, but calls for improvements designed to lure Californian tourist revenue up the sleepy Oregon Coast demanded a bridge.
For the Rogue River Bridge, McCullough imported avant-garde engineering from France. The Freyssinet method of prestressing concrete arches by using hydraulic jacks, to compensate for natural deformations as the bridge settled and weathered, had never been applied in the United States. McCullough considered the project an experiment in technique and economy, and it worked. He achieved a heavy load capacity for the bridge while also creating delicately fine arches that roll like the hills behind them.
The bridge impressed engineers in America and beyond. “The thin arches add to the aesthetics, but also, from an engineering standpoint, you can really see the level of detail analysis that went into it,” Grubbs said. “It took cutting-edge engineering to develop that design.”
Also in 1931, work began on another bridge that borrowed from the Old World. The Cape Creek Bridge, 619 feet long and 104 feet high, closed the intimidating gap between Devil’s Elbow and Heceta Head. McCullough’s solution originated in ancient Rome: a two-tiered aqueduct-like crossing with a swooping arch over the small creek.
Critics dubbed the bridge and the tunnel on its southern end the “million dollar mile.” In November 1931, a local newspaper, The Siuslaw Oar, moaned, “You can’t help but wonder how in the dickens the great state of Oregon wants to make an expenditure like this to cross a little creek which isn’t more than knee deep.” Today, the iconic bridge compliments the Heceta Head Lighthouse Scenic Viewpoint and remains Oregon’s only concrete bridge of its type.
At the time, ferries still served as bridges across five coastal waterways from Newport to Coos Bay. As the Depression kicked in and the New Deal arrived in response, Oregon’s bureaucrats hustled to secure funding for a series of bridges to complete the Oregon Coast Highway. In 1933, designs began for five new bridges, at Newport, Waldport, Florence, Reedsport, and Coos Bay.
In the early days, McCullough did most of the design work himself, such as for the bridges in Astoria. By now, though, he had a diversified staff under his wing. “He’d pretty much lay out the design, and then he’d leave it up to his team of engineers to pull it together,” Hadlow said. “They were a tight-knit group. They understood each other. He had the vision, and they could make it happen.”
This teamwork, and the fact that McCullough’s engineers designed the final five bridges in a six-month span, working double shifts, forged a sense of architectural continuity. “Those five bridges look like siblings,” Hadlow said. “Then you have Gold Beach down south which is a little earlier and maybe looks more like a cousin. No two of the coast bridges are alike, but they make a family.”
Work began on all five bridges by August 1934. To meet Public Works Administration funding requirements, construction was labor intensive: handsaws and wheelbarrows replaced their mechanized kin. The projects together employed more than 1,000 laborers, consumed more than two million man-hours of work, and cost $5.6 million at the time.
The Yaquina Bay Bridge at Newport, with its 600-foot parabolic through arch, has endured as one of McCullough’s most acclaimed. “That bridge is all aesthetic to me—it’s not even the engineering,” Higgins said. “The fact that you think it’s art and it still serves an engineering purpose is what makes
Unfortunately, McCullough’s Alsea Bay Bridge at Waldport no longer exists. Corrosion within the reinforced concrete deteriorated the triple-arched bridge, which was demolished in 1991. Art Deco pylons, spires, and some railing from the original bridge still stand at the new bridge’s north end.
In Florence, the double-leaf bascule Siuslaw River Bridge will still open when required by river traffic. Its drawspan shows similarities to McCullough’s Astoria bridges, and its tied arches, identical to those designed for Alsea Bay and the Umpqua River bridges, have their roots in the Wilson River Bridge. The concrete pylons display a classic Art Deco sunburst pattern.
The Umpqua River Bridge at Reedsport also opens for shipping. The bridge’s main arch rotates on a massive bearing. “The entire span twists and swings way out there,” Grubbs said. “Just thinking of the technology and the mechanical engineering feats of that, it’s very impressive, especially given the time in which it was designed and constructed.”
At 5,305 feet in length, the Coos Bay Bridge is the longest of the coastal McCullough bridges. Its steel double-cantilever truss design accommodates a 150-foot vertical clearance above the bay. Stylized grand staircases descend the bridge’s ends, landmarks of a slower, bygone era of travel.
All five bridges opened to traffic in 1936, several with full celebratory fanfare, but without McCullough in attendance. In late 1935, McCullough left his engineers in charge of the projects’ completion so he could accept the federal government’s invitation to design several spans along the nascent Pan-American Highway. In two years time, McCullough designed and oversaw construction of three suspension bridges, in Panama, Honduras and Guatemala.
These would be the final bridges of McCullough’s career. Upon returning to Oregon in 1937, the state highway commission made McCullough assistant state highway engineer. He had proven his administrative skills as state bridge engineer, and Oregon’s highway system was evolving fast. But in May 1946, McCullough suffered a massive stroke. He passed away shortly afterward and was buried in Salem. State officials renamed the Coos Bay Bridge in his honor the following year, and dedicated a wayside on its north end to him.
As McCullough’s coastal bridges approach their centennial, they still connect communities from Gold Beach to Astoria. The bridges’ longevity lies, in part, in McCullough’s foresight and integrity. “They did a robust design job back in the day,” said Oregon state bridge engineer Ray Bottenberg. “They designed those bridges for the biggest trucks they could anticipate at that point. We’re lucky they didn’t cut corners.”
All but the two Astoria bridges are listed in the National Register of Historic Places. Bottenberg figures the McCullough bridges’ lifespan is somewhat indefinite. “We probably could keep them until the big Cascadia earthquake,” he said. “It’s tied to how willing we are to take care of them.” Through cathodic protection, frequent painting, and other proactive maintenance, ODOT remains more than willing to preserve the coast’s jewel-like clasps.
Oregonians treasure the coastal McCullough bridges for multiple reasons, and McCullough’s legacy extends in as many directions. “On one hand he gave us some extremely aesthetic infrastructure that fits in, or even enhances, some pretty awesome scenery,” Bottenberg said. “But they’re also valuable assets to use, and that’s kind of a cool legacy in that it serves both purposes.”