Navajo Bridge

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Navajo Bridge crosses the Colorado River's Marble Canyon near Lee's Ferry in the U.S. state of Arizona. It is the only roadway crossing of the river and the Grand Canyon for nearly 1000 km (600 mi). The bridge carries northbound travelers to southern Utah and to the otherwise inaccessible portions of Arizona north of the Colorado River, such as the North Rim of Grand Canyon National Park.

View to east with 1929 bridge at left, 1995 bridge at right

Prior to the construction of the first Navajo Bridge, the only river crossing from Arizona to Utah was at nearby Lee's Ferry, where the canyon walls are low and getting vehicles onto the water is relatively convenient. The ferry offered only unreliable service, however, as adverse weather and flooding regularly prevented its operation.

Construction of the original Navajo Bridge began in 1927, and the bridge opened to traffic in 1929. It was paid for by the nascent Arizona State Highway Commission (now the Arizona Department of Transportation) in cooperation with the United States Department of the Interior's Bureau of Indian Affairs, as the eastern landing is on the Navajo Nation. The steel spandrel bridge design was constructed by the Kansas City Structural Steel Company. The bridge is 834 feet in length, with a maximum height of 467 feet from the canyon floor. Its roadway offers an 18 foot surface width with a load capacity of 22.5 tons (although the posted legal weight limit was 40 tons). During the design phase, a wider roadway was considered, but ultimately rejected, as it would have required a costly third arch to be added to the design, and the vehicles of the time did not necessitate the wider road.

In 1990, however, it was decided that the current traffic flow was too great for the original bridge, and that a new solution was needed. The sharp corners in the roadway on each side of the bridge's approach had become a safety hazard due to low visibility, and the deficiency in the original design's width and load capacity specifications were becoming problematic. The bridge had also become part of the US Federal Highway System's Route 89ALT, and it did not meet the required standards of such a road.

Deciding on a solution was difficult, due to the many local interests. Issues included preservation of sacred Navajo land, endangered plant species in Marble Canyon, and the possibility of construction pollution entering the river. The original proposal called for merely widening and fortifying the bridge, but this was ultimately rejected since this could not possibly bring it up to current federal highway standards. Replacement was then the only option, and it was eventually decided to entirely discontinue automobile use of the original bridge. A new bridge would be built immediately next to the original and have a considerably similar visual appearance, but would conform to modern highway codes.

The new steel arch bridge was commissioned by the Arizona Department of Transportation and the Federal Highway Administration, and was completed in September of 1995, at a cost of approximately $15 million dollars.

The original Navajo Bridge is still open to pedestrian use, and an interpretive center has been constructed nearby to showcase the historical nature of the bridge and early crossing of the Colorado River. The original bridge has been designated as a Historic Civil Engineering Landmark.

Contents

1 Bridge statistics

1.1 Original Bridge
1.2 New Bridge

2 External links

Bridge statistics

(Source: placards at the interpretive center.)

Original Bridge

Dedicated: June 14-15, 1929 after two years of construction
Total length: 834 ft (254 m)
Steel arch length: 616 ft (188 m)
Arch rise: 90 ft (27.4 m)
Height above river: 467 ft (142 m)
Width of the roadway: 18 ft (5.5 m)
Amount of steel: 2.4 million lbs (1,089,000 kg)

Amount of concrete: 500 cu yds (385 m³)
Amount of steel reinforcement: 82000 lb (37,000 kg)

Construction cost: $390 thousand

New Bridge

The main pin of the new bridge was set October 14, 1994, after seven months of construction.
Total length: 909 ft (277 m)
Steel arch length: 726 ft (221 m)
Arch rise 90: ft (27.4 m)
Height above river: 470 ft (143 m)
Width of the roadway: 44 ft (13.4 m)
Amount of steel: 3.9 million lbs (1,769,000 kg)

Amount of concrete: 1,790 cu yds (1370 m³)
Amount of steel reinforcement: 434,000 lb (197,000 kg)

Construction cost $14.7 million

External links

[Excellence in Highway Design: Navajo Bridge]
[The Navajo Bridge Project]
[Photographic virtual tour of the Navajo Bridge.]
[American Society of Civil Engineering - Navajo Bridge]
[Maps and aerial photos] Coordinates: [36.8178° -111.6315°]
* Street map from [Google Maps] or [Yahoo! Maps]
* Topographic map from [TopoZone]
* Aerial image or topographic map from [TerraServer-USA]
* Satellite image from [Google Maps] or [Microsoft Virtual Earth]

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