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Apr 052013
 

By Nick Worth
After more than a decade on the drawing board, the restoration project for the historic bridge over Chevelon Creek near Winslow is moving forward.
The bridge has been standing since 1913 when the State of Arizona did a truss replacement as part of the Transcontinental Route.
In 1912, the state legislature appropriated $5,500 for the project. The bridge was installed over the canyon in 1913 at a project cost of $4,985.
The bridge scored 94 points out of 100 in the Arizona Historic Bridge Inventory. The rating came because of its inclusion in the Transcontinental Route and also because it was one of the first significant road structures undertaken by the newly formed state of Arizona. The inventory also notes the bridge represents a type, period or method of construction, and is associated with significant events or patterns.
There is only one bridge (the Hereford Bridge number 9214) in the inventory that exceeds the Chevelon Creek Bridge in age and length of span.
Those historic factors, along with the current condition of the structure, are the reasons a restoration plan has long been in place for the bridge.
“This project has been on the books for quite a while,” said Navajo County Engineer and Assistant Public Works Director William Bess. He and county Civil Engineer Bryan Cook noted that the current bridge restoration project was originally started prior to June 2002 and has gone through multiple attempts to get to the construction stage.
“We went to bid in 2006 during the construction boom,” said Bess. “All the bids came in too high.”
At the time, the estimated cost of the restoration was figured at $503,800, but one bid was more than double that estimate at $1,257,711 and the other was more than triple at $1,680,415.
The bridge project was then put on hold until additional money could be found.
In 2010, the county became eligible for additional funding for the project through the Arizona Department of Transportation (ADOT) and the Northern Arizona Council of Governments (NACOG). The money came through bridge rehabilitation funding and the bridge qualified because an ADOT inspection rated the structure below 30 percent “sufficiency.”
Cook said a brand new bridge with no problems would earn a sufficiency rating of 100 percent.
“It’s still safe for traffic,” noted Cook. He said the under 30 percent rating had the advantage of opening up an additional $500,000 in federal funding for the project.
The next turn in the road for the restoration project came in 2011 when the Hopi Tribe purchased a ranch on which the west end of the bridge rests. Because of the land transfer, ADOT declared a previous agreement no longer valid and a new agreement was put together during the following months.
An amendment to the joint project agreement for the additional bridge rehabilitation financing was received in 2012, but by the time it was completed, the construction clearance window was too narrow and the county would have had to pay for an additional mobilization and demobilization, so the project was again put on hold.
Also in 2012, ADOT notified the county that the project might need still more funding.
According to Cook and Bess, they plan to present another amendment to the joint project agreement to the Navajo County Board of Supervisors that not only increases the project funding, but at the same time decreases the county’s matching funds responsibility.
Under the existing agreement, the county must shoulder 20 percent of the cost, with ADOT taking on the other 80 percent. The new amendment would lower the cost to the county to 5.7 percent, with ADOT paying 94.3 percent.
“We’re going to try to keep the truss system as it is,” said Cook. “We’ll keep as much steel as possible.” He said the concrete deck of the bridge will be torn out and replaced with a lightweight concrete to lessen the “dead load,” or the weight of the bridge itself. The floor system of stringers will also be reconfigured.
The project goals are to preserve the historic nature of the bridge while increasing the live load carrying capacity from the current posted limit of 10 tons to 20 tons. The bridge and the approaches to the bridge will also get safety upgrades, including a bridge barrier rail to protect the original latticework and structure from damage, transitional timber and steel guardrails on the approaches, new signage and repair, or replacement of some timber cribbing at the site.
Bess cited the timber cribbing as one of the “unknowns” in the project that will add to the work and cost of the project.
Other work to be done includes repair or replacement of the existing roller bearings, installation of deck joints that will protect the bearings and anchor bolts from weather, removal of lead-based paint from the entire bridge structure and repair of any damaged steel members.
Cook said the chosen contractor will have the option of doing the needed repairs on site, or bringing in a crane, lifting the bridge and taking it to another site to perform the needed work, then replacing it when finished.
Bess noted that if the work is done on site, the contractor would have to “bag” the sections of the bridge on which the work is being performed in order to prevent debris from falling into the creek.
Bess said ADOT is in charge of putting the bridge project out for bid, hiring a contractor and overseeing the project. The county will also oversee the work as owner of the structure.
“It should take another one to two months for the bidding process, maybe longer,” Bess said.
Cook said he expects construction to begin toward the end of this summer and the project will finish in 2014.
Recalling the extreme bids for the project in 2006, Bess said he’s hoping for different results this time around. “We’re hoping with the economic situation today, we’ll have some contractors with really sharp pencils,” he said.

 Photo by Bryan Cook A long planned restoration project on the historic Chevelon Creek Bridge is moving forward, with construction expected to begin by the end of this summer. The bridge is set to receive new approaching guardrails, as well as a new, lightweight concrete deck and removal of lead-based paint, among other improvements.


Photo by Bryan Cook
A long planned restoration project on the historic Chevelon Creek Bridge is moving forward, with construction expected to begin by the end of this summer. The bridge is set to receive new approaching guardrails, as well as a new, lightweight concrete deck and removal of lead-based paint, among other improvements.