When the Kaibab Trail Suspension Bridge was completed, it was the sole Colorado River crossing in a 754-mile stretch from Needles, California, to Moab, Utah. Because of the Colorado River and the canyons' travel barrier, the bridge remains one of the few area crossings.
With the exception of a suspension bridge a half-mile downstream, the Kaibab Trail Suspension Bridge is the sole physical Colorado River crossing within 340 miles, from Hoover Dam downstream to Navajo Bridge upstream. They have both been recognized as National Historic Civil Engineering Landmarks.
It is located within the Grand Canyon, which is among seven natural wonders of the world. The suspension bridge spans 440 feet across the Colorado River. It fosters backcountry recreation and connects the South and North Rims of the Grand Canyon.
The bridge serves the Grand Canyon National Park Service and concessionaire employees, backpackers, hikers, pack trains that haul supplies to Phantom Ranch, and mule riding tourists. Four 550-foot cables that are stabilized by two wind cables suspend the structure.
The bridge has not been modified since the original construction. It remains in service and endures approximately 100,000 crossings each year. The bridge has been designated by the American Society of Civil Engineers as a National Historic Civil Engineering Landmark.
History of the Kaibab Bridge
Before there was a bridge, the only choices to cross the Colorado River were boats or swimming. One man swam across the river in an attempt to reach a boat on the other side and resupply provisions. He made it across the river but his clothes did not. A naked man had to wrap in a blanket and seek help.
Two surveyors who attempted to cross by boat. Wooden boats tend to dry out in the sun and shrink and deteriorate. The men drown. Shortly after the drowning, Francois Mathis decided his surveying crew needed a better boat to cross the river. He ordered a two-piece steel boat that was transported by mules.
In 1908, David Rusk built a trail down the Grand Canyon from the North Rim trying to promote tourism on the north end. He realized that things were going well on the South Rim. There was a tent camp at what is now Phantom Ranch. He realized in order to be successful, there had to be a way to cross the river.
With much difficulty, he and a few men rigged a cableway to cross the river. It consisted of a steel cage. When he built the cableway he had to improve a trail to go up to the Tonto Trail, somewhat like today's South Kaibab Trail, and connect to the Bright Angel Trail near the Indian Garden.
The first two passengers to cross the river using the cableway were women who came down from the South Rim. The cage was damaged in a flood in 1917. It is unclear whether it was put back in use. Grand Canyon National Park was created in 1919.
The development of the park was underway to serve tourists and visitors. The Park Service realized the importance of having a better way to get across the river. In 1920, they built the first suspension bridge. It was a bit flimsy. The design of the bridge could carry one mule and one person at a time.
In a strong wind storm, it is reported the bridge would turn over. It was damaged at one time by a wind storm and repaired. Within a few years, the Park Service realized and understood that this bridge was not what they needed if they were going to promote tourism or there were going to be lots of mule rides.
Something more substantial was needed. That lead to the design and construction of the current bridge. The 1928 bridge was built in almost the same place as the 1920 bridge. It was 16 feet higher. The old bridge stayed in place while they built the new bridge.
On today's bridge, you go through a tunnel to enter the bridge from the south side. On the 1921 bridge, there was a pathway on the other end that left the bridge. A tunnel was blasted through the rock for the new bridge. There is a spiral in the Kaibab Trail that leads to the north elevation on the other end of the bridge.
Constructing the Bridge
This bridge was designed and constructed with some significant design control. These are things that provide boundaries on how the bridge is able to be designed. Almost every piece of the bridge is less than ten feet long and weighs less than 200 pounds.
That is what could be carried down by a mule. All the steel members of the bridge meet those criteria. The only exception was the suspension cables above and wind cables that stabilized the bridge. The wind cables were brought down by a mule pulling a sled.
The wind cables were smaller in diameter and did not weigh as much as the suspension cables. The bridge was wide enough for a mule, but not wide enough for it to turn around and cause havoc. From canyon wall to canyon wall, the bridge is 440 feet long.
The suspension cables are quite a bit longer, at 550 feet. Mules carried most of the materials down a winding trail where they were unloaded in a yard, so to speak. There were four 550-foot cables that were two inches in diameter and weighing over 2000 pounds each that were carried down by 42 men.
Background of Men Who Built the Bridge
Most of them were members of the Havasu tribe. The area was part of their original homeland. It is thought there were Havasu living, at least part of the year, in the Indian Garden right below the South Rim. The construction engineer wrote a report at the completion of the bridge.
It said, 'These cables were carried down on the backs of 42 Indians. Each man carried about 50 pounds and would make a round trip in two days. It was about seven miles from the head of the trail to the bridge, a drop of 5000 feet. The Indians carried their own food, and when they got to the bottom of the canyon, after getting rid of the cable, went down onto a flat, gathered brush, made sort of a trench of it, and placed big boulders on the brush, then set fire to it.
The bridge was built before the days of OSHA. The construction would likely not have passed those safety standards. Men were required to wear respirators, however. County officials and the Arizona State Mining Inspectors got wind of the fact, early on, that men were working without this kind of protection, and a letter was sent that slapped the hands of the Park Service for having unsafe working conditions.