After 56 years, it’s time for the old Gila River Bridge to retire…

Located on US 70 about a mile west of the Bylas community on the San Carlos Apache reservation, the bridge, which was built in 1957, is now being demolished.

But don’t worry. Motorists will still have a bridge to serve their needs. In fact, the new bridge sits right next to where the old bridge stood.

We told you about this project last summer, but here’s a little refresher:

The old 23-span steel girder bridge was in use until the new 15-span precast concrete girder bridge was constructed and opened to drivers. The $12.7 million replacement project not only gives drivers a new bridge with wider travel lanes and emergency shoulders, but the project includes intersection improvements and a pedestrian walkway, too.

You can see in the video above that the need for a new bridge stemmed from the condition of the old bridge – it was just inadequate for the needs of traffic in the area.

“We’ve had weight limitations for the last couple of years, so the big trucks can’t even cross the bridge,” Safford District Resident Engineer Brian Jevas says.

Safford District Engineer Bill Harmon explains further…

“The bridge that’s being demolished right now was constructed in 1957 and it was showing its age. It was what we call functionally obsolete – it was narrow,” says Harmon, adding that the new bridge has wider lanes, shoulders and a walkway.

Once demo on the old bridge is complete by the end of next week, crews will still need to come back to the site and finish up some paving work. That’s scheduled to start in mid-April and should be done by the end of May.

One more bit of information…
Demolition crews have taken steps to prevent pieces of the old bridge from falling into the water below.

Since the river is running very narrow right now, the water is only below one of the 23 spans of the deck. Beneath that deck is a chain-link net to catch large debris coming off the old bridge during demolition. Downstream from the bridge, a catchment fence has been placed in the river bed to capture any smaller debris so it can be removed from the river channel.

We posted a clip on YouTube last week that shows crews demolishing the old Pantano Union Pacific Railroad Bridge. Because it’s a time-lapse video, you can watch all the work being completed in under a minute…

In reality, the effort took a little more time. In fact, work began long before crews and equipment even got to the site. As you can see in the video above, planning started several months in advance of the I-10 closure and bridge demolition.

In addition to holding traffic safety management meetings, ADOT checked in with communities in the area to make everyone aware of the plans. ADOT also met with businesses, alerted the media and activated message signs in preparation of the big event. Communication and coordination were vital to this project’s success.

After all the work (both before and during the bridge demo), lanes on I-10 were opened to traffic as scheduled.

As you can see in the video above, work to replace the San Pedro River Bridge is in full swing…

Construction started Oct. 1 and continues until March, which is when the project will shut down for about six months to accommodate the summer migratory bird season in the San Pedro riparian wilderness area. Work starts back up again in Oct. 2013 and is on schedule to finish by spring 2014.

This project is designed to replace the existing San Pedro River Bridge (built in 1955!) with a new structure featuring wider traffic lanes and shoulders that meet current standards and provide adequate space for vehicles.

You might remember that we blogged about this project a few months ago and highlighted the public involvement process. People in the community told ADOT they wanted the highway to stay open – at least partially – during construction.

That feedback helped shape the project and the construction schedule…

“The community let us know during the planning phase of this that they didn’t want us to completely shut the highway down and do the construction of the bridge,” says ADOT Senior Community Relations Officer C.T. Revere in the video above. “So we kept a lane open and the traffic signal is controlling the traffic through there.”

Besides community comment, the bridge’s location has also played a role in shaping the project…

As illustrated in the video above, the bridge’s locale – it sits in one of two congressionally designated national riparian conservation areas in the country – has factored into how crews are working to construct the new bridge. Wattles and sediment barrier are in the plan along with a re-seeding and planting plan that includes the replacement of trees that were taken down for construction.

“Some of those trees had to be removed because the bridge is going to be wider than the existing one,” Revere says in the video. “The one that’s there now is 26-feet wide. The new one will be 44 feet wide. Also the construction activities to build the new bridge required us to have some clearance.”

Public involvement truly helps shape ADOT projects … just ask residents living near the San Pedro River Bridge.

Their local bridge sits on SR 90 and is slated for replacement – construction has already begun, in fact.

But, way before work got started earlier this week those residents took part in several ADOT public meetings where they were given a couple of different construction schedule alternatives.

One option called for a full closure of SR 90 at the San Pedro River…

That choice would have allowed the bridge replacement to wrap up in a six-month time frame, but it would have meant very lengthy detours for residents. The option was eliminated after comments from residents indicated a preference for a longer project schedule that would be able to keep SR 90 open through the duration.

18-month construction schedule – no extended full closure
“We’ll have a six-month construction period, six months of shut down for the summer migratory bird season in the San Pedro riparian wilderness area, which is where the bridge project is, and then six more months to finish the bridge,” says ADOT Senior Community Relations Officer C.T. Revere.

What else do drivers need to know?
This bridge, constructed in 1955, will be replaced by a new structure featuring wider traffic lanes and shoulders that meet current standards and provide adequate space for vehicles – including emergency responders, bicycles and pedestrians.

Construction on the $7 million bridge replacement project started Oct. 1 and once work is complete (by spring 2014), drivers can expect:

• A new 44-foot wide bridge that replaces the existing 26-foot wide bridge.
•  Two 12-foot traffic lanes and 10-foot shoulders in both directions.
• Improved guardrails, and roadway and bridge approaches.
• A new bridge that’s six feet higher than the existing structure (this is to comply with 100-year floodplain requirements.

Drivers also should take note of this project’s impact on traffic…

• A temporary traffic signal will guide alternating traffic through a single shared lane during construction. Wait times are expected to be 5 to 8 minutes, with delays of up to 15 minutes possible. Motorists are advised to plan ahead and allow extra travel time.
• Some overnight closures of SR 90 will be required for the safety of the public. Those scheduled closures will be announced in advance.
• ADOT intends to have one lane open in each direction with no traffic signal during the season that construction work is shut down.

By Kimberly Noetzel
ADOT Public Education Manager

The Phoenix-area's newest pedestrian bridge is in place over Interstate 17 just north of Happy Valley Road.

ADOT installed the 160-ton, 600-foot long bridge over two nights in June next to the Central Arizona Project (CAP) canal.

Working in partnership with the CAP, city of Phoenix and Federal Highway Administration, ADOT designed and built this bridge to provide long-term connectivity for the CAP's multi-use recreational trail. Because the city of Phoenix will maintain the bridge, ADOT designed it to require only minimal maintenance after installation.

When you drive under or walk over the bridge, you might wonder why a new structure looks so … weathered. The answer? Weathering steel. Crews used weathering steel which, by design, gives outdoor structures a rustic appearance. Better yet, it never needs to be painted, which significantly reduces maintenance costs.

Weathering steel has what’s known as a "sacrificial surface." This means it rusts only on the outside. The base metal (structural component) does not rust. If you hail from the eastern United States, you might know that some big, old steel bridges need to be replaced over time because they rust all the way through and weaken...

But, with weathering steel, the load-bearing capacity and long-term durability of a bridge or other structure are not compromised.

In the Metro-Phoenix climate, the weathering process usually takes about six months and a couple of good rains. But for this project, we’ll let you in on a little secret: to jump start the weathering process crews sandblasted the steel and hosed it down prior to installation, making our new bridge look older than it really is to complement the natural environment.

The bridge, which is accessible from the CAP trail, is now open.

This might sound cliché, but ADOT really is getting rid of the old to make room for the new…

It’s happening right now on the San Carlos Apache reservation as ADOT crews construct a new bridge to replace the US 70 Gila River Bridge at Bylas.

That existing 23-span steel girder bridge will remain in use until the new, 15-span precast concrete girder bridge is constructed just adjacent to it (so, technically we’re not getting rid of the old until after we finish constructing the new, but you get the point).

About the project
The bridges (old and new) are located on US 70, about one mile west of the Bylas community. The existing bridge – constructed in 1957 to carry US 70 traffic over the Gila River – is 1,829 feet and among the longest bridges in Arizona. It has served its purpose well, but after 55 years of use, the bridge is outdated and doesn’t meet modern standards.

It’s time for an update
The $12.7 million replacement will not only give drivers a new bridge with wider travel lanes and emergency shoulders, but the project also includes intersection improvements and a pedestrian walkway.

Work began in February and is expected to wrap up by the fall. That’s when the new bridge will open to traffic and the old bridge will be demolished. Crews will come back in spring 2013 to pave the bridge and new highway approaches. But don’t worry, the bridge will be drivable this fall – it just won’t have asphalt pavement because it will be too cold to pour the pavement.

P.S. You know how we love to document bridge demolitions here on this blog, so you better believe we’ll have more on this project as it continues. We promise to bring you video coverage the bridge demo later this year!

By Danelle Weber
Public Information Officer

The bridge crossing the Gila River outside Florence has quite a few distinctions in its history. It was the first bridge to cross a major river in Arizona. It was the only bridge in Arizona to cross the Gila River for much of its early history. It has also been rebuilt three times … talk about high maintenance!

The first try
Before Coolidge Dam was built and before the canal system began siphoning the river’s water supply, Gila River was quite formidable. It ranged from 150 to 1,200 feet wide and from two to 40 feet deep. It could pump 6,070 cubic feet of water per second into the Colorado River.

For a long time, the most popular story to tell about the river included a stagecoach driver, a soldier, two nuns, and a gambler. (We know — it sounds like the start of a bad joke.)

While trying to ford the river, the driver had his passengers hang on the outside of the carriage to keep the current from carrying away the stagecoach. According to the story, while the nuns prayed and the gambler cursed, the soldier was the only one to encourage to the driver.

Needless to say, it used to be a bit of a problem to cross Gila River, especially when it was flooding.

By 1885, Florence residents, miners and business owners were hungry for the means to cross the river safely and regularly. The price tag was well over $15,000, which would be nearly $20 million by today’s standards. It was 965 feet long and 16 feet wide. It had redwood piles, pine decking and a 30-ton iron truss. Just about everyone couldn’t be happier about the bridge. Everyone, that is, except for Territorial Gov. Conrad Zulick, who felt the bridge was “a wanton misappropriation of public funds.”

It was to everyone’s surprise and chagrin that a wooden bridge would suffer serious damage from swiftly running water and seasonal fires.

Once more, with feeling
By 1905, it was obvious that the bridge would need to be redone. In 1910, the first territorial engineer, James B. Girand, took on Florence Bridge and rebuilt it — this time with concrete and steel. Despite his best efforts to make the bridge as formidable as the river, however, a severe winter storm in 1914 washed away both approaches.

The newly minted concrete bridge was now a concrete island.

It was repaired, of course. Then, another storm in 1915 badly damaged it again. And again in 1916.

And again in 1917.

Senator Marcus Smith, one of Arizona’s first two, said the bridge had become a “monument to the treachery of the river.”

The feds step up to the plate
In 1916, Congress passed and President Wilson signed the Federal Road Aid Act. Is it any wonder that Arizona would try to get its hands on the very first federal monies it could to solve that thorn in its side, Florence Bridge? Because of Gila River’s treachery, Florence Bridge holds the distinction of being the first transportation project in Arizona to receive federal funds.

Federal Aid Project No. 1, as the rebuilding project was called, dug in its heels and attempted to fix Florence Bridge once and for all. The project extended the bridge by 750 feet. They were confident this extension would do the trick.

Well, the river saw our mere human attempts to tame it and raised us a raging current and another four decades of near-constant damage. Touché, river.

Starting from scratch … again
By the 1950s, the Arizona Highway Department had had enough of the money pit that was Florence Bridge and made plans to redesign and replace it entirely. The new structure was higher, wider, and longer than the 1910 version. At 1,507 feet long, it was made of 30 50-foot spans. The new bridge had a steel I-beam stringer superstructure and concrete substructure and piers. The deck was 35 feet wide and featured steel balustrade guardrails.

Since its completion in 1957, the bridge has only required two alterations: one in 1995 to replace the guardrails, and one in 2000 to repair the superstructure. Both seem fairly minor when you consider the continual repairs that used to be necessary. It seems that we have finally built a bridge worthy of crossing Gila River.

This article is part of ADOT’s Transportation History series in honor of Arizona’s centennial. The source for the information in this article comes from the ADOT-researched text “Arizona Transportation History” and the Arizona Historic Bridge Inventory.

If you follow us on Facebook, you might have seen the photo we posted yesterday as part of our “Where in AZ?” series...

It was a pretty cool shot taken from very high up ... 900 feet above the Colorado River, in fact! Yes, our crew was at the Mike O’Callaghan-Pat Tillman Memorial Bridge and snapped the photo.

The bridge is truly a marvel and is seen as a very important link between Arizona and Nevada for travel and commercial transportation, allowing traffic to bypass the Hoover Dam.

So, when we heard the bridge had been honored with the American Society of Civil Engineer’s (ASCE) 2012 Outstanding Civil Engineering Achievement award, we were not surprised.

The announcement was made last month during the ASCE’s annual gala. From the ASCE’s website ...

“(The bridge) was constructed in a harsh environment where temperatures reached triple digits during the day. The structure is the highest and longest arch concrete bridge in the Western hemisphere and features the world’s tallest concrete columns.

Because of the 800-foot gorge below with rock cliffs, steep canyon walls and winds of up to 70 miles per hour, the contractor used two 2,500 foot long cableways connected to 330 foot high towers on each side of the canyon to transport the construction crews and 50 tons of equipment and material into place during the construction.

Due to the high heat, concrete was poured from mid-air at night and was cooled with liquid nitrogen filled tubes. The bridge is part of the five-mile long bypass that consists of four lanes of roadway, eight bridges, interchanges in both Arizona and Nevada and over 3.6 million cubic yards of shot rock excavation.

The project was built for $240 million without a dispute or claim by contractors. Obayashi Corporation and PSM Construction USA were contractors for the bridge while HDR, T.Y. Lin International and Jacobs Engineering were the design and support team. The project is owned by the Arizona Department of Transportation, the Nevada Department of Transportation, the U.S. Bureau of Reclamation, the Western Area Power/Administration and the National Park Service. The Central Federal Lands Highway Division of the Federal Highway Administration was the project and program manager.”

Big congratulations to all involved! More information on the bridge can be found online.

When you’re building bridges, there’s more than one way to get the job done...

We told you a few months ago about a method that utilizes false work and sand jacks. Today, we’re going to fill you in on a different approach … the key terms to remember are soffit fills and waste slabs.

If you recall, false work is what secures the bridge structure as it is being built and until it can stand on its own.

A soffit fill (basically a big pile of dirt) acts much in the same way.

After the bridge piers and abutments are cast, the area in between is filled with dirt. That dirt is piled right up to the height of where the bridge deck eventually will sit … this soffit fill will act as the false work, providing a strong foundation to build the bridge on top of.

With the dirt in place, a thin concrete slab – the waste slab – is poured on top (see video above). The flat, smooth surface is what crews will build upon, but the waste slab won’t be a part of the finished bridge. No, the job of a waste slab is to simply give crews a form on which to pour more concrete.

Maybe a little analogy right about now might help you get the picture. Take a second and think about making a pie (trust us!).

Your counter top is acting as the soffit fill – giving you a surface to work on. Now imagine your pie pan as the waste slab – it’s giving you a form to shape your crust, but after the pie comes out of the oven, you’re not going to need the pan … your piece of pie will stand on its own!

OK, with us still? You’ve got your counter top (soffit fill) and your pie pan (waste slab), but before you place the pie crust you want to make sure it won’t stick to the pan … maybe you’ll use some non-stick cooking spray?

That’s kind of what crews use out in the field. They spray a thin wax coating over the waste slab so when they pour the concrete for the actual bridge structure on top, it won’t stick. Because remember the waste slab is just that – waste. It’s only there to temporarily provide a surface for the building of the bridge, but eventually it will be removed along with the soffit fill.

From there, crews complete a number of additional steps...

Keeping with our pie analogy – there’s “filling” involved with some bridges. In the case of the bridge being built at the Loop 303 and Waddell Road, the crews are actually building “lost decks,” so named because the materials ADOT uses in the framework will remain inside the bridge structure for the lifespan of the bridge.

These “lost decks” are inside the bridge and give it strength, but also allow for some open space, because a bridge of this size made entirely of concrete would be too heavy.

After the filling is inside, all that’s left to do is place the top crust, a.k.a. the top deck, which is what motorists will eventually drive on.

Crews will then bring in heavy-duty equipment to remove the soffit fill and the waste slab, but we’re going to save that for another blog post … so stay tuned!

Last week we were asked on Facebook to provide an update on the Loop 303 project – specifically the bridge construction at Waddell Road.

We’re happy to oblige! We also are glad to report that the bridge construction is progressing as planned.

Crews are scheduled to pour the southbound stem walls this week and the northbound stem walls in early April. By the way, stem walls are supporting structures that join the foundation with the vertical walls built on the foundation.

With stem walls in place, crews will move onto deck work.

Interestingly, they’ll be forming “lost decks,” so named because the materials ADOT uses in the formwork will remain inside the bridge structure for the lifespan of the bridge.

Looking ahead, the schedule calls for deck pours in late April and, by May, drivers should see crews excavating the dirt mound that sits out there today.

That dirt mound actually plays a very important role: It’s a dirt soffit that is supporting the bridge structure during the construction process until the bridge can support itself.

Another look at the work being done near Waddell Road.

For this project, ADOT is using the dirt-soffit method – which saves both time and money – during bridge construction instead of the false work method that most people are accustomed to seeing.

The dirt-soffit method can be used because the bridges being built do not need to maintain traffic flow during the construction process.

The Waddell Road Bridge should be complete this summer and Waddell Road will re-open. Then, work will move a mile south to Cactus Road and repeat the process during bridge construction there. Fear not local motorists: We will not close Cactus Road until we have fully re-opened Waddell Road!

Stay tuned to the blog for more on the Loop 303 project ... next week we’ve got a video coming your way that helps explain how crews build a bridge from the ground up!