91-year-old Grand Canyon bridge named an engineering landmark

A 91-year-old bridge connecting the northern and southern rims of the Grand Canyon was recognized Saturday afternoon as a National Historic Engineering Landmark. The American Society of Civil Engineers celebrated the Kaibab Trail Suspension Bridge's designation with Grand Canyon National Park leaders and Grand Canyon Historical Society members at a physical landmark commemorating the achievement.

American Society of Civil Engineers President Robin Kemper reaches for a handshake as Jonathan Upchurch,
an ASCE Fellow, unveils a plaque commemorating the South Kaibab Suspension Bridge's designation
as a National Historic Civil Engineering Landmark. (Photo: American Society of Civil Engineers)

The bridge, also called the "Black Bridge," is one of two suspension bridges over the Colorado River in the span of 340 miles. It lies between the Navajo Bridge to the east and the Hoover Dam to the west. “The Kaibab Trail Suspension Bridge is a prime example of engineering innovation," ASCE President Robin Kemper said in a written statement. "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.” ASCE says the 440-foot bridge has allowed hikers to cross the canyon since it was completed in 1928 and remains unaltered to this day.

Before 1907, the only way to cross the river was by boat, a dangerous method which cost many lives. Then, outdoorsman David Rust built a privately-operated cableway. The cableway was a six-foot by ten-foot steel cage large enough for one mule or several people would carry passengers across the river, but the passage was considered precarious. Theodore Roosevelt used the cableway in 1913. The second crossing was a suspension bridge that lacked stiffness. It was built in 1920 and proved to be too flexible to safely carry pedestrians across the river as the number of visitors to the park was increasing.