Originally Published: October 3, 2008 10:46 p.m.
PRESCOTT - Road engineers, concrete masons and Native Americans are turning the Highway 69-89 overpass near old Fort Whipple into a work of art. Mountain lions, pine trees and spiritual icons greet motorists as they drive over and under the massive concrete structure.
"We wanted to do something artistic since Prescott is surrounded by all this beauty," Bill Williams, Arizona Department of Transportation public information officer, said.
Deciding the icon designs is the first step in creating highway art.
"We asked the City of Prescott and the Yavapai-Prescott Indian Tribe what they would like to see," Williams said. "The tribe wanted to show its cultural heritage and the city wanted pine trees."
Icons adorn the bridge's walls and abutments.
Engineers draw designs to exact measurements. The drawings are digitized and used to cut Styrofoam templates called block-outs.
"We send the computer files to a company that cuts the block-outs," Andy Roth, ADOT resident engineer, said. "Sometimes a block-out comes back as one piece, and others, like the basket design, come back in a lot of pieces. We have to put those together like a giant jigsaw puzzle."
The concrete walls are poured in 30-foot sections. Steel forms hold wet concrete in place while it cures, or dries. Wood forms are usually used for sidewalks and driveways, but steel is used for bridges.
Cranes place two steel forms - one for each side of a wall - on the ground. Workers build a wood frame on the form, similar to a picture frame, cut a piece of hard liner to fit the frame and glue the icon pattern to the liner.
"The tricky part is that the forms are on the ground when we attach the block-outs so we have to lay them opposite of how they will appear," Tom Billings, senior project manager for FNF Construction, said. FNF is doing the concrete work. "So, we are always working from a mirror image."
Before gluing the block-outs, puzzle masters fit the jigsaw pieces together.
"Once everything is ready, we raise the walls and start pouring," Billings said.
Icons are poured with the wall. They are not attached or cutout later.
Concrete masons use hand-held vibrators to force wet concrete around the block-outs and to fill air voids, or bubbles. Vibrators enable the concrete to form deer antlers, sunrays and animal legs.
When the forms are removed, workers chip the Styrofoam from the hardening concrete.
"We pour one day and remove the forms the next day," Roth said.
Project stakeholders agree on color swatches before icons are painted.
A large basket icon replicates the weave pattern found in a Yavapai-Prescott basket. Its block-out arrived in about 25 pieces, Roth said.
Motorists exiting off Highway 89 toward Prescott may notice a procession of critters in what Roth calls "the chase scene."
A mountain lion trails behind a deer, the deer is following a coyote and a roadrunner is leading the pack.
"We are all really proud of how this is turning out," Roth said.
Visitors may view some finished icons from the Prescott National Cemetery.
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