ADOT Bridges

PODCAST: How does ADOT look after all of those bridges along state highways?

PODCAST: How does ADOT look after all of those bridges along state highways?

PODCAST: How does ADOT look after all of those bridges along state highways?

PODCAST: How does ADOT look after all of those bridges along state highways?

By Steve Elliott / ADOT Communications
January 26, 2025
Pinto Creek Bridge on US 60

Listen to the episode! (or use the player below)

Arizona's highways feature more than 8,500 bridges ranging from wee to grand. Whether or not a highway trip takes you across Pinto Creek Bridge on US 60, Navajo Bridge on US 89A or Glen Canyon Bridge on US 89, you're almost certain to benefit from one of our bridges. 

Arizona has an enviable record for the condition of state highway bridges. Some of that has to do with the relative youth of our infrastructure, but it also has a lot to do with the work of ADOT team members like David Benton, our State Bridge Engineer. 

David joins On the Road With ADOT this week to share how his team looks out for the health of Arizona's bridges. Listen to him visit with host Doug Nintzel, and may come away with an appreciation for not just for that historic SR 88 trust bridge at Canyon Lake and what goes into keeping it in good condition. 

You can subscribe to episodes of On the Road with ADOT through Apple Podcasts and Spotify. You also can find episodes at azdot.gov/Podcast and featured in ADOT Blog posts.

This Phoenix street was once part of transcontinental highway US 80

This Phoenix street was once part of transcontinental highway US 80

This Phoenix street was once part of transcontinental highway US 80

This Phoenix street was once part of transcontinental highway US 80

By Kathy Cline / ADOT Communications
July 30, 2024
A roadway with two low-clearance underpasses, bordered by a sidewalk and a fence, stretches into the distance under a bright, clear sky.

During the early days of Arizona’s roads, many local streets carried highway traffic, some of which were transcontinental highways. 

A great example is the 17th Avenue Underpass in downtown Phoenix, near the Arizona State Capitol. This structure once carried the tracks of the Southern Pacific Railroad over US 80. 

US 80 was a major transcontinental highway that ran from San Diego, Calif., all the way to Savannah, Ga. In Arizona, US 80 traveled from Yuma to the Arizona-New Mexico state line by way of Phoenix. At 17th Avenue, US 80 left Buckeye Road, heading north past the capitol to Van Buren Street.

The underpass itself was part of a Depression-era movement to eliminate on-grade railroad crossings. The structure was designed and completed in 1935 by ADOT’s predecessor, the Arizona Highway Department. It’s a concrete rigid frame with two 25-foot spans over the northbound and southbound lanes of the street. The deck was 80 feet wide to accommodate the multi-track railyards, with smaller openings for pedestrian sidewalks at both sides. The structure also incorporated decorative touches, like slotted concrete guardrails.

Interstates 8 and 10 gradually replaced US 80 and 17th Avenue now carries local traffic. The 17th Avenue Underpass is a well-preserved example of bridge construction of the time, as well as a reminder of what was an important transcontinental highway.

A black and white photo of a car approaching an underpass beneath a bridge on a slightly inclined road. The sky is clear, and the surroundings are free of traffic and pedestrians.

Don’t burn bridges, unless they're rebuilt with innovative techniques

Don’t burn bridges, unless they're rebuilt with innovative techniques

Don’t burn bridges, unless they're rebuilt with innovative techniques

Don’t burn bridges, unless they're rebuilt with innovative techniques

By Ryan Harding / ADOT Communications
July 6, 2022

They say it’s a good idea not to burn your bridges, and I’m inclined to agree. But if you’re going to replace it with a brand-spanking new bridge, then why not?

Another new bridge replaced an older one in the A-1 Mountain Road overpass over I-40 in west Flagstaff. Using innovative construction methods, ADOT was able to demolish and replace the bridge in less than 40 days.

In fact, new bridges have been popping up all over northern Arizona. The A-1 Mountain Road Bridge joins these new bridges that were built in the last few years:

  • Rio de Flag Bridge in downtown Flagstaff
  • I-40 bridges over Business 40 in west Flagstaff
  • Fourth Street Bridge in east Flagstaff
  • Meteor City Road Bridges near Meteor Crater
  • I-40 Hughes Avenue Bridge to Bellemont

Many of these bridges were replaced using time-saving techniques that cut down on traffic impacts, like precasting bridge elements off-site, the bridge-slide method and geosynthetic reinforced soil-integrated bridge system

Have gone a bridge too far?

Just wait as ADOT continues to work on replacing the I-40 bridges at Pineveta Draw near Ash Fork, the I-15 Virgin River Bridge No. 1 in the northwest corner of Arizona and the Lukachukai and Agua Sal North bridges along US 191 in the Navajo community of Round Rock.

ADOT is also rehabilitating bridges along I-40 at Hermosa Drive in Holbrook, Seligman at Exit 123 and Anvil Rock Road 11 miles west of Seligman. 

Check out more bridge content on our website.

Gillespie Dam Bridge still standing

Gillespie Dam Bridge still standing

Gillespie Dam Bridge still standing

Gillespie Dam Bridge still standing

Kathy Cline/ADOT Communications
October 24, 2021

It may not look like much from afar ... but the Gillespie Dam bridge is a survivor in one of the most notorious bridge-problem areas in Arizona.

Building on the Gila River has always been a challenge. The floodplain is a very turbulent one, and the Antelope Hill bridge (the original site for a bridge across the river) sustained severe damage time and again from floods. In addition, continual flood damage to the newly-established Ocean-to-Ocean Highway led state officials to reroute the road between Wellton and Arlington (south of the river, through Gila Bend). However, since Arlington was north of the river, a new crossing had to be built.

After a few years of problems and false starts (including a flood that washed away much of the construction equipment and materials), the Gillespie Dam Bridge was opened for traffic in 1927. It remained part of the old U.S. 80 mainline until 1956, when the road was re-aligned. It now functions as a county bridge and is part of Historic U.S. Route 80.

The Gillespie Dam bridge was one of the longest vehicular structures in Arizona when it was originally built; it was also the only steel bridge across the Gila River, and one of two remaining bridges with multi-span vehicular through trusses. The Gila River Flood of 1993 only caused some support piers to settle (because of its design and concrete support piers sunk in bedrock). It's one of the most important examples of early bridge construction in Arizona.

 

 

ADOT starting project to protect I-17 Verde River bridge footings

ADOT starting project to protect I-17 Verde River bridge footings

I-17 101 traffic interchange

ADOT starting project to protect I-17 Verde River bridge footings

ADOT starting project to protect I-17 Verde River bridge footings

October 20, 2021

CAMP VERDE – An Arizona Department of Transportation project to improve the Verde River bridges on I-17 near Camp Verde is underway to add capping to the bridge footings in the river bed to prevent erosion, protecting vital infrastructure on the primary route between Phoenix and Flagstaff. 

The work utilizes a method to channel river flow through the work zone by constructing a temporary “earthen bypass channel” to contain the river flow so crews can safely work outside of the area placing concrete caps over the footings of the Verde River bridges.

The channel is 60 feet wide and designed to handle the normal river flow of the Verde River. The channeling of the Verde River will occur in two phases as crews work on the 12 total bridge footings.

In order to protect wildlife, ADOT has teamed up with biologists from Northern Arizona University who are onsite anytime crews are working. One biologist recently found a northern Mexican gartersnake, an endangered species, and safely relocated the reptile. In addition all project personnel onsite had to take a training class on the endangered species in the area.

There will be no impacts to traffic on I-17 while work is occurring. River users, however, will be required to exit the river and go around the project site.

The project is anticipated to be completed by spring 2022.

For more information, visit azdot.gov/projects and click on the Northcentral District.

You can help the Fourth Street Bridge project in Flagstaff win a national award

You can help the Fourth Street Bridge project in Flagstaff win a national award

You can help the Fourth Street Bridge project in Flagstaff win a national award

You can help the Fourth Street Bridge project in Flagstaff win a national award

By Ryan Harding / ADOT Communications
October 13, 2021

We are so excited to announce that for the second year in a row, an ADOT project is in line for a national award from America’s Transportation Awards! In the transportation industry, this is a BIG deal! 

The Fourth Street Bridge replacement project in Flagstaff, which won a regional award in the 2021 America’s Transportation Awards competition, has made it to the Top 12 finalists to compete for one of two national awards - the Grand Prize and the People’s Choice Award.

While the Grand Prize is decided by an independent panel of industry experts, the People’s Choice Award is decided by the general public through online voting. Last year, when the Loop 202 South Mountain Freeway made the Top 12, we asked a big, but simple favor from you to go online and vote daily for that project. 

We’re asking the same favor from you this year! Go online and vote for the Fourth Street Bridge project each day from now until Oct. 25! Every vote counts!

Need some reasons why you should cast your vote for the Fourth Street Bridge project? Happy to oblige:

  • The Fourth Street Bridge has improved community connectivity in Flagstaff by adding more lanes for vehicles to use and a protected path for pedestrians and cyclists!
  • The new bridge helps make it easier for students at nearby Northland Preparatory Academy to get to-and-from school.
  • The bridge also connected the Flagstaff Urban Trail System across Interstate 40, allowing trail hikers to continue along uninterrupted.
  • The bridge was replaced using the “bridge slide” method, in which crews slide the new bridge into place of the old one using hydraulic jacks. This method cut an estimated two months off of construction time and saved nearly $7 million.

Anyone, anywhere can vote. If you’re a Flagstaff resident who has benefited from the new Fourth Street Bridge, now is the time to show your support through voting! Follow this direct link to vote not just once, but every day, for the Fourth Street Bridge through Oct. 25.

As an added bonus, the winning project gets a $10,000 cash prize donated to the charity of the state DOT’s choice. So voting not only gives this well-deserving project national kudos, but it will help benefit a local charity as well!

So do us a solid and set a reminder on your smartphone to vote daily for the Fourth Street Bridge project and give Arizona a chance to shine in the transportation world! 

Dinnebito Wash Bridge project winding down on SR 264

Dinnebito Wash Bridge project winding down on SR 264

Dinnebito Wash Bridge project winding down on SR 264

Dinnebito Wash Bridge project winding down on SR 264

By Laurie Merrill / ADOT Communications
September 28, 2021

Looking at State Route 264 on a map, it appears as a jagged east-west line in the northeast corner of Arizona.

But appearances can be deceiving. SR 264 is a vital connecting corridor for the Hopi Tribe and other area motorists, much like State Route 51, Loop 101 and Interstate 17 are for Phoenix area commuters.

Winding from US 160 near Tuba City, the state highway links together all 12 Hopi villages and continues on past Steamboat and Ganado and other destinations. The 154-mile Arizona portion ends at the New Mexico state line near Window Rock, where it continues east as NM 264.

This is why the Arizona Department of Transportation rehabilitation of the Dinnebito Wash Bridge on SR 264 near Hotevilla-Bacavi, milepost 363, is so important.  

The deck replacement project, which is nearing completion, is located west of Third Mesa, one of three mesas on the Hopi Reservation that are comprised of the 12 Hopi villages.

Despite it's importance to SR 264 travelers, by bridge standards, this bridge is short at only 212 feet long, said Mokarr

Dennebito Wash Bridge project
om Hye, Senior Bridge Engineer with the ADOT Bridge Group.

“The main work is replacing the bridge deck,” Hye said. “We demolished it completely. We are increasing the deck thickness.”  

Originally constructed in 1955, the steel girder bridge allows travelers to cross the Dinnebito Wash about three miles west of Hotevilla-Bacavi Village and 40 miles east of Tuba City.

“It is in a remote area, which makes it challenging,” Hye said. “It is really in the middle of nowhere.”

There’s no quick and easy way to get to milepost 363 on SR 264 from central Phoenix. It’s a 276-mile journey starting with Interstate 17 northbound to Flagstaff, Interstate 40 eastbound to Winslow, State Route 87 northbound to the town of Second Mesa and then heading west on SR 264, past Hotevilla-Bacavi to the destination.

Crews are in the second phase of the project. They’ve poured concrete on one half the bridge and are working on the other half.

Since the rehabilitation started in May, SR 264 has been reduced to one lane of alternating travel on the bridge from 6 a.m. to 6 p.m. daily, including weekends.

“In terms of schedule, we are on schedule,” Hye said. “The roadway is scheduled to reopen this fall.”

Innovative Flagstaff bridge project in line for national award

Innovative Flagstaff bridge project in line for national award

I-17 101 traffic interchange

Innovative Flagstaff bridge project in line for national award

Innovative Flagstaff bridge project in line for national award

September 24, 2021

FLAGSTAFF – The Arizona Department of Transportation’s Fourth Street Bridge replacement project in Flagstaff is receiving national recognition. The project is among a list of 12 in line for national awards from the American Association of State Highway and Transportation Officials (AASHTO). 

The innovative bridge project has already won western regional recognition. For the national award, the three highest-scoring projects from each regional competition earn a place on a “Top 12” list of projects competing for the national Grand Prize – selected by an independent panel of industry judges – and the People’s Choice Award, chosen by the public through online voting. In addition, those top national winners each receive $10,000 in cash awards to be donated to a charity or scholarship of the state DOT’s choosing.

"This project has provided improved access to our campus for our students and families. It also has created safe and healthy alternatives for students who want to walk to school or ride their bikes," said David Lykins, superintendent at Northland Preparatory Academy, a charter school located near the southern end of the Fourth Street Bridge.

The new, wider bridge not only benefits the academy helping students get safely to and from school, but also boosts economic development in the area with better traffic flow and more mobility options.

ADOT State Engineer Dallas Hammit explains the innovative bridge-slide method utilized for the project, “We used a slide technique where the new bridge was built just east of the old one. That allowed us to move the new structure into place in about two weeks. This greatly decreased the inconvenience to the traveling public.” 

After the old bridge was demolished, crews used hydraulic jacks to “slide” the new bridge into place. The method cut an estimated two months off of construction time and saved nearly $7 million over traditional bridge construction methods. This reduced the impact to the local community during construction as well as creating a wider bridge that allows vehicles and pedestrians to safely cross. View a time-lapse video of crews moving the new bridge into place at vimeo.com/442491601

Online voting for the People’s Choice Award begins Sept. 24. AASHTO will then announce the winners of both the Grand Prize and People’s Choice awards in October at the AASHTO Annual Meeting in San Diego. Members of the public can visit this link to vote for ADOT’s Fourth Street Bridge project and learn more about all the nominees at americastransportationawards.org.

This is the second year in a row ADOT was honored with the Top 12 recognition. Last year, ADOT’s Loop 202 South Mountain Freeway was named to the list.

You pour the coffee, we’ll pour the concrete (for a new bridge)

You pour the coffee, we’ll pour the concrete (for a new bridge)

You pour the coffee, we’ll pour the concrete (for a new bridge)

You pour the coffee, we’ll pour the concrete (for a new bridge)

By Doug Nintzel / ADOT Communications
August 23, 2021

In another chapter of “while you were sleeping,” we tell the story of the overnight work that recently went into creating the concrete deck for the northbound side of the Interstate 17 bridge that’s under construction above Central Avenue in Phoenix.

For ADOT, the I-17 bridge over Central Avenue had reached the end of its service life. Makes sense, since it originally opened to traffic back in 1962.  Over the past year the old bridge has been demolished in phases and a new bridge has taken shape south of the downtown area.

One of the last major moves was the concrete pour for the new northbound bridge deck. It takes a number of loads of concrete shipped via trucks. And as you can see in this ADOT I-17/Central Ave Bridge Video, an extended boom pump system delivered the concrete from street level on Central Avenue up to the bridge deck. It reminds me of a series of fire hoses that pump concrete instead of water.

Crew members then poured the concrete into the network of steel rebar that provides strength for the bridge deck. Specialized equipment, including a Bidwell pavement roller, is then used to spread and smooth the concrete pavement that drivers will be traveling on within a matter of months.

For this particular operation, 545 cubic yards of concrete were poured for this span in just a matter of hours.

So let’s review the project’s advances since work started in May 2020. Project phases included demolishing and reconstructing the southbound side of the steel-girder bridge. I-17 traffic, which had temporarily been sharing the old northbound side of the bridge, was then shifted to the new southbound span earlier this year. In turn, that allowed the same type of demolition and reconstruction work to take place for the new northbound side of the bridge.

Now it’s on to the last stages of work to finish the entire bridge so I-17 traffic can once again travel through the area with three lanes in each direction. The new structure will be wider to accommodate regional plans for additional lanes along I-17 when future funding is available. Increased clearance below along Central Avenue will provide more room for commercial trucks as well as Valley Metro’s future South Central Avenue light-rail line.

The $13.5 million project has been funded in part by Proposition 400, a dedicated sales tax approved by Maricopa County voters in 2004.