Natchez Trace Parkway Bridge facts for kids
Quick facts for kids Natchez Trace Parkway Bridge |
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The Natchez Trace Parkway Bridge, viewed from the north
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| Coordinates | 35°59′12″N 86°59′32″W / 35.9866°N 86.9923°W |
| Carries |  Natchez Trace Parkway |
| Crosses |  SR 96 |
| Locale | Williamson County, Tennessee |
| Maintained by | National Park Service |
| ID number | 5570463P0000000 |
| Characteristics | |
| Design | Arch |
| Total length | 1,572 ft (479 m) |
| Width | 37 ft (11 m) |
| Height | 145 ft (44 m) |
| Longest span | 582 ft (177 m) |
| Clearance below | 107 ft (33 m) |
| History | |
| Designer | FIGG Bridge Engineers |
| Opened | March 22, 1994 |
| Statistics | |
| Daily traffic | 210 (in 1997) |
| Toll | none |
The Natchez Trace Parkway Bridge is a really cool and unique bridge in Williamson County, Tennessee. It's also known as the Double Arch Bridge at Birdsong Hollow. This amazing concrete bridge is 1,572 ft (479 m) long. It carries the two-lane Natchez Trace Parkway 145 ft (44 m) high over State Route 96 and a beautiful, wooded valley. It's about 8.7 mi (14.0 km) from the northern end of the Natchez Trace Parkway.
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The Amazing Natchez Trace Parkway Bridge
The Natchez Trace Parkway Bridge is sometimes called the Natchez Trace Parkway Arches. It was the very first concrete arch bridge in the United States built using a special method called "segmental construction." This means it was put together from many smaller pieces.
How the Bridge Was Built
The bridge's arches are made from 122 hollow box segments. These segments were made in Franklin, a town nearby. Each segment was about 9.8 ft (3.0 m) long. They weighed between 29 and 45 short tons, which is like the weight of several elephants!
The top part of the bridge, called the deck, has 196 more precast segments. These are trapezoid-shaped and typically 8.5 ft (2.6 m) long. The parts of the deck right above the arch's highest point are 13 ft (4.0 m) deep. The base and supports of the bridge were built right on site.
A Special Design
The main arch of the bridge is 582 ft (177 m) long and perfectly balanced. The second arch is 462 ft (141 m) long and a bit different because of the valley's slope. What makes this bridge really special is that it doesn't use vertical columns to hold the deck up from the arch. Instead, the bridge's weight is focused at the top of the arch.
This design choice gives the bridge a very clean and open look. It's often called a "cathedral arch" bridge because of its elegant appearance.
The bridge was designed by Figg Engineering Group. It was built by PCL Civil Constructors Inc. They used a method called "balanced cantilever" to build the arches and deck. Temporary cables held each arch in place from the piers and valley sides until it was finished. This method helped protect the valley's environment by avoiding lots of temporary support towers.
The bridge cost about US$11.3 million to build. It was finished in October 1993 and officially opened on March 22, 1994.
Awards and Recognition
The Natchez Trace Parkway Bridge has won many awards for its amazing design. In 1995, it received a Presidential Award for Design Excellence. The Federal Highway Administration gave it an Award of Merit in 1996.
In 1994, the Eleventh International Bridge Conference called it the most outstanding achievement in the bridge industry for that year. The judges were very impressed by its beautiful double-arch design. They felt it showed great respect for the history and natural beauty of the area.
The bridge even appeared on the album cover for the Christian rock band Newsboys. It's featured on their 2004 album Devotion.
Gallery
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The bridge viewed from State Route 96, looking southeast
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A closer look at the bridge's end shields
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The bridge stretching across the valley, looking south
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