Bridges of Yesteryear

BRIDGES Gesteryear

In early territorial Arizona, land of few rivers, bridges were largely regarded as unnecessary. The few that appeared were usually poorly built and maintained and commonly washed out in floods or collapsed under heavy loads. Some consisted of no more than two parallel boards laid across a streambed. Given the choice between crossing a river on an early timber bridge or fording at stream level, a traveler was often better off taking to the water.Despite chronically tight budgets, Arizona counties did manage to erect a handful of substantial bridges during the 1880s and '90s. The simplest and cheapest of these early structures consisted of a wooden deck laid over a row of timber stringers, or beams, supported by timber piles. With abundant raw materials close at hand, concrete was also used extensively. For short spans, concrete slabs were laid over concrete supports. For longer reaches, builders used reinforced concrete arches.

The truly long-span bridges almost always involved iron or steel trusses, weblike structures comprising many comparatively short pieces of metal joined together in a series of structural triangles. Perhaps the earliest of this type and the longest county-sponsored example was erected by Pinal County in 1885. Built over the Gila River at Florence, the structure consisted of two 180-foot iron trusses, with a long wooden-trestle approach over an island and slough. That bridge lasted only a short time.

After the turn of the century, the territorial government tried to weave a highway system from a crazy quilt of county roads-a job that in 1909 fell to J. B. Girand, Arizona's first and only territorial engineer. His entire staff consisted of a clerk and a draftsman. Girand's strategy was to link the county seats and larger towns through a network of graded but unsurfaced roads. As part of this effort, he supervised construction of bridges at several key crossings. Curiously, none of these bridges even remotely resembled any other in the system.

Will our outdated but admirable vehicular spans be preserved? Their chances improved when 81 venerable Arizona bridges were recently added to the National Register of Historic Places. Two of them were Chevelon Creek Bridge (OPPOSITE PAGE) and Woodridge Bridge (ABOVE). Both are in Navajo County.

Girand's first effort was a replacement for the Florence Bridge, which had been left high and dry when the fickle Gila River meandered from beneath it, forcing travelers to use a ferry on those infrequent occasions when the river carried water.

For the new bridge, Girand designed a 700-foot multiple-span concrete girder structure that was then constructed by inmates from the nearby territorial prison. The prisoners were kept under guard in a barbed wire stockade when not working on the project. Averaging 55 men, the convict crew labored until the bridge was completed in December, 1910.

a 700-foot multiple-span concrete girder structure that was then constructed by inmates from the nearby territorial prison. The prisoners were kept under guard in a barbed wire stockade when not working on the project. Averaging 55 men, the convict crew labored until the bridge was completed in December, 1910.

In the next two years, Girand also built a small concrete arch over Mule Gulch east of Bisbee; a steel truss over the Verde River at Camp Verde; a timber trestle over Forest Wash; a timber-and-iron truss over the Black River near Fort Apache; and numerous smaller spans.

Without question, the most spectacular, expensive, and significant of the territorial bridges was the multi-arch structure over the Salt River at Tempe. Designed by Girand in 1910, the Tempe Bridge also was built using convict labor. It was opened ceremoniously in September, 1913, and immediately carried the heavi est traffic of Arizona's highway spans. Originally called the Ash Avenue Bridge, it still stands, unused but impressive, just downstream from the Mill Avenue Bridge, which was completed in 1931.

By the time Arizona was admitted to the Union on February 14, 1912, the territorial government had laid more than 243 miles of highway and built about a half-mile of bridges - a figure almost doubled a year later by the Tempe Bridge. Girand was replaced that year by Lamar Cobb, and the territorial engineer became the state engineer. Little else changed initially in highway operations. In fact, several road and bridge projects begun by the territory-including Tempe Bridge were taken over by the state without interruption. Statehood soon brought increased funding and many more bridges. As residents gained more mobility and tourists began streaming into the region in autos and excursion buses, officials of the state engineer's office, renamed the Arizona Highway Department, began to pursue an aggressive policy of new construction.

The 1910s and '20s were a memorable period of bridge building in Arizona. Supplementing the work of the state highway department, counties erected numerous bridges on secondary roads. And federal agencies built some of the state's most important bridges, including the spans at Topock, Sacaton Dam, Cameron, and Dead Indian Canyon. Together the several levels of government created a rich variety of technological expression, ranging from multiple-span concrete girders, graceful concrete arches, and steel trusses to spectacular steel arches that seem to fly over rugged canyons. Most of the state's surviving historic bridges date from this period.

Among these structures, Navajo Bridge over the Colorado River is clearly the most dramatic. It was originally planned as a suspension bridge, then as a through arch (in which the arch extends above the roadway rather than supporting it from below); but eventually highway depart ment bridge engineer R. A. Hoffman designed it as a long-span steel-deck arch. With funding assistance from the Navajo Tribe, the state contracted with the Kansas City Structural Steel Company in June, 1927, to fabricate and erect the arch. The contractors faced severe logistical prob lems in building the immense bridge, hauling equipment and material 130 miles north from Flagstaff over a route with, in many places, no real road. By April, 1928, the men had set the concrete foundations into the sheer canyon walls. The steelworkers who balanced high above the river refused safety netting, insisting that with it they might become careless. Despite the obvious hazards, only one workman was killed during construction of the bridge. The first steel for the bridge was swung into place that April; the main span was completed on June 14, 1929. At its completion, Navajo Bridge represented a milestone in engineering design, logistical planning, and construction. Arching

BRIDGES

(RIGHT AND BELOW, RIGHT) Canyon Padre Bridge in Coconino County and Colorado River Bridge at Yuma, flanked on the right by a railroad bridge. A number of state spans built in the 1920s and '30s, now functionally obsolete and too costly to rehabilitate, face an uncertain future. But the Arizona Department of Transportation has taken the initiative in studying and, in some cases, preserving them.

(BELOW) Designed by engineer R. A. Hoffman, Navajo Bridge over the Colorado River in northern Coconino County is Arizona's most dramatic and significant antique bridge structure.

BRIDGES

(ABOVE) Close-up view of bridge railing at Canyon Padre shows deterioration of concrete. (TOP) Star-crossed Antelope Hill Bridge in Yuma County was struck twice by Gila River floodwaters and eventually abandoned.

high above the Colorado River-the highest span in the country at completion-Navajo Bridge remains Arizona's most significant vehicular structure. Although a new bridge of similar design is planned for this crossing, the original Navajo Bridge will remain in place, to be used as a pedestrian walkway.

While bridge building proved remarkably successful, there were embarrassing failures as well. Early highway engineers, seemingly oblivious to the fact that a river's gentle trickle could abruptly turn into a raging torrent, often built the piers over foundations poorly placed on alluvial sand or shallow bedrock, and did little to protect against the scouring action of fast-moving floodwaters. As a result, bridges collapsed in whole or in part when the piers toppled toppled over.

Among Arizona's rivers, the Gila proved the most vexing. The reconstructed bridge at Florence required extensive repairs after almost every major flood. San Carlos Bridge, built over the Gila in 1913, was periodically impassable for five of its first seven years, until an extension was added. The bridge over the Agua Fria River at Coldwater (now Avondale) was still under construction in 1916 when parts of it began washing away. Even the redoubtable bridge over the Salt River at Tempe required major reconstruction after flooding in 1919 caused settlement of some of its piers.

The most notorious of these early structures was Antelope Hill Bridge over the Gila River, east of Yuma. Completed by convict labor in 1915, the bridge was dedicated in a gala celebration on October 24. Governor George W. P. Hunt and hundreds of guests sat at long wooden tables on the dry riverbed in the shade of the bridge, drinking lemonade and eating barbecued beef and beans "until they could eat no more." The visitors then formed a long line, strolled across the bridge, and returned to the riverbed for several euphoric rounds of speechmaking. "It made a merry and never-to-be-forgotten picture," reported the Yuma Sun.

But before memories of the picnic had faded, the bridge was in trouble. In less than three months, floodwaters washed away almost two miles of approach road and widened the channel at the bridge's north end by 300 feet. Reopened in August, 1918, it was heavily damaged in the Thanksgiving flood of 1919 and again three months later. The highway department waged a constant battle to keep the star-crossed structure in one piece.

"The Antelope Hill Bridge is located at a point where it is impossible to control the river and keep it under the bridge at any reasonable cost," lamented state bridge engineer Merrill Butler in 1921. "Foundation conditions are bad, and a permanent extension would necessarily be long and costly with the strong pos sibility that the same situation would again develop in a few years." Within two years, the engineers had rerouted the road to bypass the bridge entirely.

Once completed, the bridge over the Colorado River at Yuma carried traffic well enough. The trick lay in getting it built in the first place.

Bureau of Indian Affairs engineers in Washington designed the bridge in 1914-without benefit of any visit to the state! The main-span truss was to be built with traditional means, using temporary wooden falseworks to support the truss during construction. The engineers had not counted on the river's unpredictable nature, however; and after two major washouts, the contractors threw away the drawings and erected the truss on a barge near the bridge site.

On March 3, 1915, schools were closed in Yuma and thousands of people lined the riverbanks to watch the great truss being swung into position on the piers. The barge was moved and the bridge put into place in a tensely choreographed maneuver. When the delicate job was finally done, the crowd cheered and whistles blew around the town.

Today, many of Arizona's historic bridges face an uncertain future. Super-seded by more sophisticated engineering designs, most are functionally obsolete and have been replaced or are threatened with replacement. Aging structures built in the 1910s and '20s are often under-designed for contemporary vehicle loads, too narrow for today's volume of traffic, and frequently damaged by careless drivers. Many can no longer meet minimum highway standards without extensive restoration. Unlike historic buildings, which can be rehabilitated for uses other than those originally intended, bridges are shaped and sited to fulfill a very specific function. This limits their potential for preservation. As a result, Tempe Bridge, Queen Creek Bridge near Superior, Dome Bridge near Yuma, and others are now closed to traffic and stand virtually abandoned.

Fortunately, such distinguished structures have found a champion of sorts in the Arizona Department of Transportation. The department recently completed a statewide inventory of pre-1945 bridges to earmark those worthy of preservation. As a result, 81 vehicular spans in Arizona were subsequently placed on the National Register of Historic Places. Seven of these possess national significance. Additionally, the department has scored several preservation successes in recent years in its bridge rehabilitation program.

The Pumphouse Wash Bridge in Oak Creek Canyon is a good example of sensitive restoration, as is the recent reconstruction of the Little Lithodendron Wash Bridge near Holbrook.

It will take this kind of sensitivity and

The old adage "If it ain't broke, don't fix it" (or in this instance, don't replace it) apparently did not apply in the case of the 60-year-old Hol-brook Bridge over the Little Colorado River.

Built with a Warren pony truss (in which the weight-bearing steel structure flanks the bridge, rather than supporting it from above or below), the bridge was deemed historically significant and was listed on the National Register of Historic Places, along with 80 other Arizona bridges. But it no longer met the traffic needs Vision to insure that Arizona's historic bridges survive. Victims of previous neglect and objects of current interest, many of the structures pictured here would not have lasted another decade without a concerted effort to save them.

of the community, and expanding it proved impractical. So down it came in December, 1988, and up went a brand-new four-lane span.

But because of its historical value, Holbrook Bridge the elder was not scrapped. It now reposes solemnly in the Navajo County Yard in Holbrook, where it waits for a new home. So far, there have been no takers.

Today the former location of the old bridge, which served this north-eastern area of the state for three generations, is distinguished only by a small identifying marker. -R.G.S.

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