Navajo Bridge - WikiHQ

Navajo Bridge is the name of twin steel spandrel arch bridges that cross the Colorado River in the Grand Canyon National Park (near Lees Ferry) in northern Coconino County, Arizona, United States. The newer of the two spans carries vehicular traffic on U.S. Route 89A (US 89A) over Marble Canyon between Bitter Springs and Jacob Lake, allowing travel into a remote Arizona Strip region north of the Colorado River including the North Rim of Grand Canyon National Park.

Prior to completion of the first Navajo Bridge, one of the only Colorado River crossings between Arizona and Utah was located about upstream from the bridge site, at the mouth of Glen Canyon where Lees Ferry service had operated since 1873. The ferry site had been chosen as the only relatively easy access to the river for both northbound and southbound travelers. By the 1920s, automobile traffic began using the ferry, though it was not considered a safe and reliable crossing due to adverse weather and flooding regularly preventing its operation.

The dual spans of Navajo Bridge are tied at ninth place among the highest bridges in the United States with nearly identical heights of for the original span, and for the second span.

The original bridge is in length, with a maximum height of from the canyon floor. The roadway offers an 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 require a wider road. When the Bridge officially opened on January 12, 1929, the Flagstaff paper proclaimed it "the biggest news in Southwest history."

By 1984, however, Arizona Department of Transportation officials decided that the 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 approach had become a safety hazard due to low visibility, and deficiencies resulting from the original design's width and load capacity specifications were becoming problematic. The bridge had also become part of US 89A.

left|thumb|A view of the bridges and [[Marble Canyon from the Colorado River, September 2009]]

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 debris entering the river. The original proposal called for merely widening and fortifying the 1928 bridge, but this was ultimately rejected as not sufficient to meet contemporary federal highway standards. Replacement became the only option, and it was eventually decided to entirely discontinue vehicular traffic on 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 May 1995, at a cost of $14.7 million. A formal dedication was held on September 14, 1995.

Bridge characteristics

Original bridge (1929)

Construction started June 30, 1927

Bridge opened to traffic January 12, 1929

Total length:

Steel arch length:

Arch rise:

Height above river:

Width of the roadway:

Amount of steel:

Amount of concrete:

Amount of steel reinforcement:

Construction cost: $390,000 (equivalent to $ million in )