EDZ Irigary Bridge facts for kids
Quick facts for kids |
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EDZ Irigary Bridge
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 Location in Wyoming
Location in the United States
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| Nearest city | Kaycee, Wyoming |
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| Area | less than one acre |
| Built | 1913 |
| Built by | Canton Bridge Co. |
| Architectural style | Pennsylvania through truss |
| MPS | Vehicular Truss and Arch Bridges in Wyoming TR |
| NRHP reference No. | 85000427 |
| Added to NRHP | February 22, 1985 |
The EDZ Irigary Bridge is a historic bridge located in southeastern Johnson County, Wyoming. This special bridge uses a design called a Pennsylvania truss. It was first built in 1913 near Sussex, Wyoming. Later, in 1963, the bridge was carefully moved to its current location on Irigary Road. Because of its history and unique design, the bridge was added to the National Register of Historic Places in 1985. This means it's recognized as an important historical structure.
Contents
Understanding the Bridge's Design
The EDZ Irigary Bridge uses a design called a Pennsylvania truss. This design is a special version of an older bridge type called the Pratt truss. The Pratt truss was invented in 1844 by Thomas and Caleb Pratt.
What is a Pratt Truss?
Imagine a bridge made of triangles. In a Pratt truss, the vertical (up-and-down) parts and the diagonal (slanted) parts work together. The diagonal parts slope down towards the center of the bridge. The inside diagonal pieces are stretched tight (under tension). The vertical pieces are pushed together (under compression). This design helps the bridge support heavy loads.
How is a Pennsylvania Truss Different?
The Pennsylvania truss is a more advanced version of the Pratt truss. It adds extra, shorter support pieces (called "struts" or "ties") in the top or bottom sections of the bridge's panels. These extra pieces make the bridge even stronger and allow it to span longer distances. This design got its name because the Pennsylvania Railroad was one of the first to use it for their bridges.
Hundreds of Pennsylvania truss bridges were built across the United States. However, this design became less popular after the 1930s. Today, only a few of these bridges are still standing. The EDZ Irigary Bridge is very important because it has a clear span of 200 feet (about 61 meters). This makes it the longest county bridge still in use in Wyoming. It is considered one of the most significant historic bridges in the state.
Building and Moving the Bridge
The story of the EDZ Irigary Bridge involves its original construction and a big move.
Original Construction in 1913
On February 4, 1913, Johnson County decided to build this bridge. It was meant to cross the Powder River near Sussex, Wyoming. This spot is about 20 miles (32 kilometers) east of Kaycee, Wyoming. The parts for the new bridge were made by the Canton Bridge Company in Canton, Ohio. This new bridge replaced two older bridges that were located about 6 miles (9.7 kilometers) north at Powder River Station-Powder River Crossing.
Life Around the Original Bridge
The small town of Sussex, Wyoming grew up around this new bridge. In 1914, the Sussex Post Office and Store was built there. A famous route called the Black and Yellow Trail was created in 1915. This trail used the new bridge to cross the Powder River. However, the trail was later moved a few years later through Arvada, Wyoming to the north. The road at Sussex eventually became Wyoming Highway 192.
Moving the Bridge in 1963
In 1963, a new concrete bridge was built. It was placed about 200 yards (183 meters) upstream from the old EDZ Irigary Bridge. Instead of tearing down the old steel bridge, it was decided to move it! The Etlin Construction Company from Casper, Wyoming carefully moved the bridge. Today, the bridge crosses the Powder River about 18 miles (29 kilometers) downstream from its original Sussex location. You can find it on Johnson County Road 172, also known as Irigary Road.
Images for kids
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Early postcard
