91视频

Multnomah County and the聽Oregon section of the American Society of Civil Engineers last week celebrated the history of three approximately century-old Portland bridges: the Hawthorne, Steel and Broadway.

In a day when math problems were scribbled on paper and most people still drove around in horse-drawn carriages, the bridges鈥� modern day use is a testament to the historic ingenuity that went into their construction. The ASCE hung plaques on each bridge commemorating their histories.

鈥淭he added interest I think is not only is it historic and it looks great and you can go back in time and trace some history, but the important thing is it鈥檚 used every day in the way it was intended on the very first day,鈥� said Frank Sherkow, an ASCE member and engineer who teaches at Oregon State University. 鈥淭hat鈥檚 not true of a lot of historic properties. It鈥檚 not something in a museum.鈥�

Built in 1910 for $511,000, the Hawthorne Bridge is the oldest working Willamette River bridge in Portland and possibly the oldest working vertical lift bridge in the world. It was designed by a prolific engineer, John Alexander Low Waddell, who built thousands of structures around the world in the first part of the 20th century. Because engineering schools weren鈥檛 common in the late 1800s, Sherkow said, Waddell was likely an apprentice to a civil engineer.

Sherkow said the Hawthorne Bridge was built to replace two bridges (named Madison one and two) after one burned in 1902. It was named after Hawthorne Avenue, which was named for J.C. Hawthorne, the founder of Oregon鈥檚 first mental hospital.

Today, the Hawthorne Bridge is crossed by approximately 30,000 vehicles, 800 TriMet buses and 8,000 bicyclists every day.

Built in 1912 for $1.7 million, the Steel Bridge is the second oldest bridge on the Willamette and is unique because it is the world鈥檚 only double-deck bridge with independent lifts for each deck. Waddell also designed the Steel Bridge; its lift mechanism is similar to the one on the Hawthorne, but much more complicated.

鈥淭he designer is now evolving his craft and his knowledge as his career advances, which is interesting too,鈥� Sherkow said. 鈥淚t鈥檚 a story not only of the bridge and construction and the companies that funded and built it, but it鈥檚 also a story of the advancement of the science of bridge engineering.鈥�

It鈥檚 called the Steel Bridge because rather than wrought iron, the Union Pacific Railroad and the Oregon Railroad and Navigation Co. built the bridge from steel 鈥� a relatively new material for the West Coast at the time.

Sherkow said maintenance for the bridge lift mechanisms isn鈥檛 simple; parts must be reconstructed, which requires intuitive thinking about the original design.

鈥淭oday, an engineer has to kind of put themselves back in time a little bit and try to determine how these things work, and can it work better?鈥� he said.

The Broadway Bridge was built in 1913 for $1.6 million 鈥� an amount that likely will be exceeded for a project to repaint it next year. The 1,613-foot-long structure was designed by Ralph Modjeski, a Polish-American engineer from Chicago.

The Broadway Bridge features a rare Rall bascule lift system 鈥� named for its inventor, Theodore Rall. The system rolls each 2,000-ton leaf section back and forth on giant bull wheels. Two similar highway bridges exist in the United States, but neither one is as large as the Broadway.

It was the golden age of American infrastructure development, Sherkow said. Railroads and bridges went up across the country, hammered together with hot rivets by people who toiled in dangerous conditions.

Most workers labored without safety nets and those who dug underground caissons often fell ill to a joint sickness known today as the bends. Hard hats weren鈥檛 even required yet.

鈥淚t鈥檚 good to take a moment, to take a step back and think about everything that goes into making these (bridges) happen and keeping them in functioning order,鈥� Sherkow said.

Block by Block is a weekly look at commercial real estate around Portland. Send suggestions for properties to [email protected].