The Longest Swinging Bridge In America

The longest swinging bridge in the US is the SkyBridge in Gatlinburg, Tennessee, at 680 feet long. This bridge uses cables attached to the side of Crockett Mountain in concrete block foundations to support its weight, along with modern architectural tools to limit the swinging on older rope swinging bridges. This pedestrian swinging bridge still operates on the same engineering principles as older swinging bridges.

What is a swinging bridge?

Swinging bridges are a simple method for foot traffic across rivers or gorges, and were especially used in rural parts of Appalachia in the late 19th and early 20th centuries. They are sometimes referred to as simple suspension bridges, rope bridges, or swing bridges.

Two main cables are used to support a deck, usually made of wood, which is connected to the cable via suspenders. This tension in the cables is what keeps the bridge standing. The cables themselves dip downward in an arc, while the deck remains flat. The cables are anchored at their ends to the ground or hillsides, which means that the bridge doesn't require towers like traditional suspension bridges.

The cables are kept anchored to a foundation or a riverbank that is high enough to keep the desk suspended above water. There is also a handrail sustem, usually in the form of additional ropes or cables, to keep the structure steady and safe.

The biggest feature in swinging bridges is their tendency to sway. Although this makes walkers nervous, it is an important part of the structure, as it can move with high winds and rain. They are cheap to make, which was ideal for people in Appalachia who often only had access to wood, iron, and rope, and required no structure in the riverbed. In addition, swinging bridges do not use towers like traditional suspension bridges.

How does the SkyBridge work?

The SkyBridge was opened to the public in May 2019. It is 5 feet wide and 150 feet above the ground at its highest point, enabling two people to walk side by side on the bridge. What makes it different from standard swinging bridges is its modern steel foundations, attached right to the side of the mountain.

The bridge has six structural cables made of galvanized steel that are attached to arched entryways at both sides of the bridge. These entryways are secured directly to the mountain via 8-foot-thick concrete foundation blocks placed 14 feet into the soil.

These entryways (known as portals) are supported via a steel frame with 44 anchor rods to tie the portals into the blocks. These foundations are enough on their own to keep the bridge standing, but there are additional safety features added in the form of micropiles, which are steel casings or bars put into the earth as a foundation in construction.

There are 16 micropiles that are placed directly into the side of Crockett Mountain; eight on the east side, and eight on the west side, ranging in length between 75 feet to 94-feet long. Three of these are in tension while others are in compression. These micropiles help add additional stability to the foundations at both ends of the bridge.

Lastly, the entire bridge has four wind guy cables, which are used to stabilize it during high wind events. However, when wind speeds reach 30 miles per hour, the bridge is shut down. Four additional micropiles were added for each of these wind guy cables.

Does the bridge swing?

While the bridge has a great deal of structural support, it is still a suspended pedestrian bridge, meaning it will swing and sway either due to the movement of pedestrians across it or due to winds across the canyon.

As visitors go across it, they will notice that the bridge arches just like traditional swinging bridges as well. In order to limit swaying, guests are not allowed to jump or sway back and forth on the bridge. In addition, the bridge shuts down in the event of major storms.

Due to the cables in the mountains and the heavy portals, the bridge can hold more than 200,000 pounds at a time, meaning that hundreds of people could be on the bridge at any one time without going over the weight limit. The foundations are the key element that keeps the bridge in tension and enables it to hold that much weight at once.

How to reach the SkyBridge

The SkyBridge is accessible not by foot but by skylift. In downtown Gatlinburg, guests can take the SkyLift that goes up on a 10-minute ride to the top of Crockett Mountain, which sits at 1,800 feet above sea level, overlooking the Great Smoky Mountains National Park.

From here, one can cross over the SkyBridge, which, right in the center has 30 feet of glass, so brave walkers can look right down to the ground below them.

The SkyBridge itself is part of the larger Gatlinburg SkyPark, which features a shopping center, hiking trails, and Tulip Tower, a 70 foot tall structure offering views of the surrounding town and Appalachian Mountains.

A proposed longer bridge in Appalachia

In 2019, there was an announcement of a bridge that would cross over two states, and would be longer than the SkyBridge by at least 40 feet. This bridge would be located in Breaks Interstate Park, the spot of a canyon between Kentucky and Virginia.

The proposed swinging bridge was planned at roughly 720 to 750 feet, depending on the source, crossing over the Russell Fork Gorge. It would begin on the Virginia side and end on the Kentucky side. It would be designed with wood and steel to blend in with the environment and serve as a traditional swinging bridge.

The project received a grant of $433,000 from the Virginia Coalfield Economic Development Authority in 2019, along with $326,000 in additional funding from other sources.

Originally, the bridge was supposed to be built in 2021, but currently the project is still delayed. One of the last updates on this project dates back to 2022, when Breaks Interstate Park Superintendent Austin Bradley said they had "secured over $1 million in funding for the construction of a pedestrian bridge across the Russell Fork River, which will serve as a spectacular new trailhead for the Pine Mountain State Scenic Trail."

Tennessee's other long swing bridge

Prior to the construction of the SkyBridge, there was another bridge that claimed the title of longest swinging bridge in America: the Bridge to Prosperity located in Sevierville, Tennessee, just outside of Gatlinburg in the Foxfire Adventure Park.

The Bridge to Prosperity is over 400 feet long, and is 70 feet above the Little Pigeon River. It is supported by cable and can handle up to six yellow school buses in weight, although it is only designed for pedestrian traffic. This swing bridge was first built around 2007 to 2010 as a tourist attraction for visitors to the Foxfire Adventure Park, alongside a covered bridge, a hiking trail up Lost Mine Falls, and a River Walk Trail.

The same engineering principles maintain SkyBridge and older bridges

While the SkyBridge has more features than older swinging bridges, such as sturdier cables and concrete foundations into the mountainside, it is still maintained by the same principle as older swinging bridges: tension. That tension enables it to stay upright across hundreds of feet, for pedestrians to pass by safely.

Modern pedestrian suspension bridges like the SkyBridge or the proposed bridge in Breaks Interstate Park bring to mind nostalgia of crossing over old rickety bridges but on a far grander scale. Yet even the delicately constructed SkyBridge will swing from time to time, allowing walkers to still feel a sense of danger as they cross over.