Grand Canyon, Ariz. — The 91-year-old Kaibab Trail Suspension Bridge, otherwise known as the “Black Bridge,” in the Grand Canyon was recognized as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers (ASCE), at a ceremony onsite attended by civil engineering leaders, Grand Canyon National Park leaders and representatives from the Grand Canyon Historical Society.

ASCE represents more than 150,000 members of the civil engineering profession worldwide. It is the oldest national engineering society in the United States. ASCE recognizes historically significant civil engineering projects, structures, and sites all over the world. More than 200 projects have earned the prestigious title for creativity and innovation, and almost all are executed under challenging conditions.

At the time of its completion, the Kaibab Trail Suspension Bridge was the only crossing of the Colorado River in a distance of 754 miles from Moab, Utah to Needles, California. Due to the travel barrier of the Colorado River and its canyons, the bridge is still one of the few Colorado River crossings in the region. Except for a suspension bridge only one-half mile downstream, the Kaibab Trail Suspension Bridge is the only physical crossing of the Colorado River in 340 miles, between Navajo Bridge upstream and Hoover Dam downstream – both of which have previously been designated as National Historic Civil Engineering Landmarks.

“As civil engineers, we take great pride in designing and constructing structures and sites that become legacies of our communities,” said Robin A. Kemper, PE, President, ASCE. “The Kaibab Trail Suspension Bridge is a prime example of engineering innovation. Engineering this bridge at the base of one of the world’s greatest wonders – the Grand Canyon – illustrates the resourcefulness and innovative spirit of the civil engineers responsible for this project.”

Built in 1928 and located within one of the seven natural wonders of the world—the Grand Canyon, the 440-foot single span suspension bridge crossing the Colorado River has fostered backcountry recreation and provides a connection between the North and South Rims of the Grand Canyon. Since its completion, the bridge has served mule-riding tourists, pack trains hauling supplies to Phantom Ranch, hikers, backpackers, Park Service and concessionaire employees. The bridge also provides a pathway that is five feet wide. The structure is suspended from four 550-foot-long suspension cables and stabilized by two wind cables. Unmodified since its original construction, the bridge remains in service today and has an estimated 100,000 crossings a year.

“The ASCE Arizona Section is incredibly grateful for this prestigious landmark designation,” said Ted Smithwick, PE, President, Arizona Section, ASCE. “The Suspension Bridge is a unique part of Arizona history and joins the ranks of iconic projects, such as the Golden Gate Bridge and the Hoover Dam.”

“The Kaibab Trail Suspension Bridge is exemplary of the park’s history and reminds us of the challenges that were required to build the bridge across the Colorado River in such an isolated location, without the benefit of modern transportation methods or technologies that we have today,” said Christine Lehnertz, Superintendent, Grand Canyon National Park. “I am proud to see this bridge recognized today as a National Historic Civil Engineering Landmark.”

The Kaibab Trail Suspension Bridge was nominated by the ASCE Arizona Section to the ASCE History and Heritage Committee in 2016. Other Historic Civil Engineering Landmarks in Arizona include the Navajo Bridge, the Theodore Roosevelt Dam and Salt River Project and the Hohokam Canal System.

For more information about ASCE’s Historic Civil Engineering Landmark Program, visit https://www.asce.org/landmark-program.

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