Glen Canyon Bridge-Technical information:1 GLEN CANYON BRIDGE General Information Purpose: Glen Canyon Unit: To create a reservoir to provide conservation storage, control sediment, abate floods, facilitate recreational development, aid in fish and wildlife conservation, and produce electrical energy. Glen Canyon Bridge: To serve as a vital link in the new highway to the remote damsite, extending between Flagstaff, Ariz., and Kanab, Utah, a distance of about 200 miles. The bridge is also essential to the transportation of construction materials and equipment by truck to the damsite as there are no rail facilities near the dam. Location: On the Colorado River in Arizona near the Utah border (approximately 17 miles upstream from Lees Ferry and 12 river miles downstream from the Arizona-Utah State line). Name Change: In the authorization, appropriations, specifications, original drawings, etc., this bridge was identified as the Colorado River Bridge. However, in 1959 the bridge was officially named the Glen Canyon Bridge as an aid in obtaining a more precise location identification. Technical Information Bridge type: Steel-arch type with a single span Height above river: Approximately 700 feet Length of bridge: 1,271 feet including abutments with an arch span of 1,028 feet Location: 865 feet downstream from axis of Glen Canyon Dam Elevation of bridge deck: 3,828 feet Bridge roadway: The concrete roadway is 30 feet wide with 4-foot sidewalks on each side Approximate construction quantities: Structural steel: 7,837,000 pounds Reinforcing steel: 371,000 pounds Handrailings: 110,000 pounds Concrete for bridge abutments, skewbacks and deck: 2,550 cubic yards Reprinted from a previously published technical record on this feature. 635 Frontispiece-Part of the crowd which attended the Glen Canyon Bridge dedication ceremony, February 20, 1959. P-557-420-03356. 1. GENERAL DESCRIPTION AND LOCATION.-The Glen Canyon Bridge across the Colorado River is a steel-arch type with a single span some 700 feet high and is the highest of its type in the United States. Its length is 1,271 feet including abutments, with an arch span of 1,028 feet, making it the second longest of its type in the United States. The bridge is located 865 feet downstream from the axis of Glen Canyon Dam. The elevation of the bridge deck at 3,828 feet is 113 feet higher than the crest of the dam. The concrete roadway is 30 feet wide with 4-foot sidewalks on each side and with 4-foot-high vertical bar type handrails. For general views of the bridge, see figures 1 and 2. The bridge is a link in the highway between Flagstaff, Ariz., located on U.S. Highway No. 89 and Kanab, Utah (fig. 3). The 24-mile access highway from Bitter Springs, Ariz., to the Glen Canyon Bridge is a paved highway built to Arizona State Highway standards by the Bureau of Reclamation under three construction contracts. From the west abutment to the Arizona-Utah State line, a distance of about 8 miles, there is a temporary paved road built by the Bureau of Reclamation; and from the State line to a point 8 miles east of Kanab, the State of Utah has constructed a paved highway which joins Utah State Highway No. 136 at that point. The nearest railroad point is Flagstaff, Ariz., 135 miles away, and the nearest town is Kanab, Utah, 80 miles west of the site. Visualized after completion of the dam is a recreational area with its tourist attraction similar to the National Park recreational area at Hoover Dam. The records show that during the last few years the latter park had more visitors than any other National Park in the United States. 2. REQUIREMENTS AND PRELIMINARY STUDIES.-At first, consideration was given to routing the highway over the dam. The crest of the dam is over a hundred feet below the rim of the canyon. To build highway approaches to fit the curved crest of the arch dam and meeting present specifications for curvatures, sight distances, and grades would have required a 90-foot-deep rock cut on one side and a tunnel on the other. Further, the crest of the dam would have to be widened and limited parking facilities, paralleling and bordering the traveled highway, would create a traffic hazard. Another and most serious concern was that until the dam was completed the two new highways, not being connected, would be of limited use to the public. Realizing that a vehicular crossing over the canyon for use during construction would be of tremendous advantage, cost estimates were made for a suspension bridge serving construction purposes only. Estimates were made for a 24-foot roadway and 2-foot safety curbs, timber floor, timber runway planks and timber railway, for an H 20 loading. Stiffening trusses, towers and cables were designed for an H 15 loading. Further, the stiffening trusses were designed using 25 percent higher than normal unit stresses for live load, and 40 percent higher stresses for a combination of live and wind loads. The cables were proportioned using a design stress of 70,000 pounds per square inch. Such a bridge was estimated to cost $1,800,000. Feasibility-type estimates were also made for a permanent bridge located approximately 1,000 feet downstream from the dam, with site data taken from available topographic sheets. The canyon rims are approximately 1,100 feet apart and 700 feet above the river. The canyon walls are red Navajo sandstone. Estimates were made for a steel arch and a suspension span and were based on a 24-foot roadway, two 4-foot sidewalks and H 20-S 16 loading. The arch had a clear span of 1,040 feet while the towers of the suspension span were 1,200 feet apart. Having made allowance in the unit prices for the difficulty of erecting the arch, the arch bridge was estimated to cost $2,920,000 and the suspension bridge $3,020,000. The cost of the two types of bridge being nearly the same, the choice fell to the arch as it offered greater flexibility in planning road approaches and vista areas, and further, was much more pleasing in appearance. 3. JOINT FINANCING AGREEMENT.-When the State of Arizona and the Bureau of Public Roads expressed their willingness to participate in the cost of a permanent crossing, all the factors previously mentioned were reconsidered. It was concluded that a permanent bridge below the dam, constructed at the earliest possible date, would be the best solution. Negotiations with the parties concerned led to an agreement whereby the cost of the bridge would be borne as follows: 637 Bureau of Public Roads State of Arizona Bureau of Reclamation $600,000 $800 000 plus 25 percent of the cost above $1.300.000 plus 75 percent of the cost above In view of the benefits derived from early completion of the bridge, it was decided to issue specifications for he bridge ahead of specifications for the dam and imit the construction period to 2 years. (a) Cast.-Construction costs av pay tems for the bridge, which was constructed under specifications No. DC-4800 are presented ater in this appendix. 4. AUTHORIZAT CN. -Construction of the Glen Canyon Bridge was authorized by an act of Aorti (Public Law 485, 34th Congress, 70 Stat. 105) and s appurtenant to the Gien Canvan unit. |