We’ve really enjoyed celebrating Arizona’s transportation history this week on the blog…

And, as we promised, we plan to keep the history theme alive throughout the state’s Centennial year. 

One way we plan to do so is to celebrate important milestones in our state’s transportation history through a new series: Today in Arizona Transportation History -- a semi-regular feature we’ll run all year long spotlighting what happened on that particular day in transportation history.

We’ll get started today … but we’re going to have to cheat a little on this one since we didn’t kick off the series last month!

Jan. 12, 1929

Back in 1929 on Jan. 12, the Navajo Bridge – complete with a 616-foot arch – opened to traffic.

Located on US 89A in northern Arizona’s Marble Canyon, the bridge was the only span to cross the Colorado River between the Green River in Utah and Topock Gorge in Arizona – a distance of some 600 miles! Because of that, the bridge was able to make a big impact on transportation and the economy of the northernmost part of the state.

This account comes from the National Parks Service website:

“It was an historic day when, on January 12, 1929, the bridge was opened to traffic. At the time, it was the highest steel arch bridge in the world and made traveling between Utah and Arizona much easier. No longer did travelers have to contend with the moods of the Colorado River at Lees Ferry.”

The bridge’s official dedication happened a few months later in June and according to NPS, it was an astounding event…

“Nearly 7,000 people in 1,217 automobiles arrived for the celebration. Speeches were given by the governors of Arizona, New Mexico, and Utah and by the President of the Mormon Church. Bands, choral groups, and Native American dancers were also a part of the festivities. It was reported that airplanes flew under the bridge and as Prohibition was in effect, the bridge was christened with a bottle of ginger ale. The bridge was known as the Grand Canyon Bridge for five years following the dedication. In 1934, after great debate in the Arizona legislature, the official name was changed to Navajo Bridge.”

The Navajo Bridge still stands today, but you can’t drive across it because now it serves as a pedestrian bridge. However, there is a newer Navajo Bridge that you can drive. It’s located just adjacent to the historic bridge, about 150 feet downstream. ADOT built the new bridge to safely handle today’s traffic loads.

When we blogged about quiet pavement back in December, we got a lot of comments…

We received plenty of questions, too, which we’ll attempt to answer here on the blog in the coming weeks – starting with one on bridge expansion joints.

But, before we get to the question let’s first take a look at what bridge expansion joints are.

Basically, expansion joints help give bridges a little “breathing” room.

Bridges made of concrete are going to expand and contract slightly for a number of reasons, including temperature changes, shrinkage of the concrete, settlement, ice and even the weight of vehicles.

Bridge expansion joints are what allow the concrete to naturally expand and contract without cracking. The rubber expansion joints are placed at the end of a bridge where it meets up with the freeway. These connectors give the concrete just enough space to move and avoid concrete cracks.

When crews are building bridges and installing the expansion joints they’re able to embed them in the concrete and make the transition flush … drivers don’t notice they’re driving over anything.

But, when asphalt rubber is placed on that bridge and the adjoining freeway, crews can’t just pave right over the joint – they need to leave a little gap to allow for the expansion joint.

In these cases, some drivers might notice a little bump. It’s a little more noticeable in the winter months as the concrete contracts and the joint expands (the opposite happens in summer). This is where our question comes in … we were asked by one of our readers if anything can be done.

To seek out the answer we turned to Tim Wolfe, ADOT’s Phoenix Maintenance District Engineer for an explanation.

He said that on smaller expansion joints crews can weld steel plates on top of the expansion joint “opening” to make for a smoother transition. In some cases ADOT crews also will mill the asphalt rubber around the gap so it “feathers” off near the expansion joint.

However, on larger bridges there are wider joints meant for taking a lot of expansion. The only option there is to remove the joint and replace it with a new one that sits a little higher. That option is a very costly fix for something that’s not a structural or safety issue. Bridge structures are inspected by ADOT and if taken at the posted speed limit bridge expansion joints should not pose any sort of safety hazard.

ADOT continues to evaluate options to improve the quality of the riding surface.

Last week we received a blog comment requesting an update on the I-17 bridges that span over Pinewood Boulevard in Munds Park. We thought it was a great suggestion and figured a blog post was in order!

But, first a little refresher …

You might remember we blogged about the bridges back in May. That’s when the first phase of construction was in full-swing and crews were working on the northbound bridge.

We told you then that this project is going to update the bridges initially built in 1958 … back when there wasn’t much development in the area. When the job is finished this fall, there will be two new bridges that will be long enough to accommodate today’s traffic levels and wide enough for a future third lane in each direction on I-17. The project also includes a new sidewalk on Pinewood Boulevard that will allow pedestrians to cross safely underneath I-17.

Where we’re at today

I-17 traffic over the new bridge.

The northbound bridge is complete and the project is in winter shutdown except for some electrical work being done.

Work on the southbound bridge will begin when the weather warms sufficiently in the spring.

When construction resumes, the southbound bridge will be demolished, then reconstructed and I-17 will be repaved through the work zone.

While this work is being done, the southbound bridge will be closed and motorists will be detoured over to the northbound lanes of I-17.

The new year officially is here, but before we dive into 2012 we’re going to take a quick look back.

ADOT’s Public Information/Media Relations team came up with a great list of the state’s major transportation accomplishments from 2011 and we thought we’d share it here on the blog!

From new freeway openings to the approval of ADOT’s Long Range Transportation Plan, here's a look at some of the highlights …

Phoenix Area Freeways:

Loop 303 Opens

ADOT widened major stretches of Phoenix area freeways in 2011 and opened the first new segment of freeway to be built under the Maricopa Association of Government’s 20-year Regional Transportation Plan. Fourteen miles of Loop 303 were opened in May between Interstate 17 and Happy Valley Parkway in Peoria, allowing drivers for the first time to use Loop 303 to make the 39-mile trip between I-17 and I-10.

HOV Lane Additions

Drivers benefited from two accelerated projects to add High Occupancy Vehicle lanes along Loops 101 and 202. The final 30 miles of HOV lanes along Loop 101 between State Route 51 in north Phoenix and I-10 in Tolleson were opened in stages during the year and completed in November. Meanwhile, in the Chandler area, 12 miles of carpool lanes were completed this fall along Loop 202 Santan Freeway between I-10 and Gilbert Road.

I-10 Widening in West Valley

Another significant milestone was marked in August with the completion of ADOT’s three-year initiative to reconstruct and widen I-10 between Loop 101 and Verrado Way. Those projects modernized I-10, transforming what had been a limited highway with two lanes in each direction into a modern freeway that now provides as many as five lanes in each direction – including carpool lanes.

State Highway System:

Mescal Road/J-Six Ranch Road Bridge

Just over six months after a fiery crash damaged the Mescal Road/J-Six Ranch Road bridge, ADOT swiftly rebuilt the bridge to reconnect the Cochise County communities of Mescal and J-Six Ranch, which were separated by I-10 and depend on the overpass for convenient access to goods, services and neighbors. While the bridge was out of service, residents and workers in the Benson-area communities were required to take lengthy detours around I-10 to reach the other side of the highway. Federal Highway Administration emergency relief funds, a shortened time frame for designing the replacement bridge and a quick construction bid process all helped put the project on the fast track. A typical bridge construction project can take up to two years.

State Route 260 Widening

Continuing a decade-long commitment to expand the capacity of SR 260, ADOT completed a project to widen the highway starting 15 miles east of Payson from Little Green Valley to Thompson Draw. The $20 million project is the fourth of six projects to construct a four-lane divided highway from Star Valley to the top of the Mogollon Rim.

State Route 87 Improvements

ADOT fulfilled its commitment to complete SR 87 improvements before the Memorial Day weekend and in time for the busy tourism season in the Rim Country. The $11.8 million reconstruction and widening project included the addition of a third southbound lane to enhance safety and traffic flow along the uphill stretch during drives between Payson and the Phoenix area. The improvements were the latest in a series of projects during the last two decades to enhance travel on SR 87, which is now a divided four-lane highway between Mesa and Payson.

US 93 Widening Project

Shortly after ADOT completed a $71.3 million widening project on the US 93 approach to the new Hoover Dam bypass bridge in 2010, the first Desert Bighorn Sheep were spotted in February using one of the three wildlife crossings that were constructed to protect motorists and provide a safe crossing for the native animals. The project earned ADOT several honors this year, including the Arizona Chapter American Public Works Association Award, 2011 Public Works Project of the Year and FHWA’s 2011 Exemplary Ecosystem Initiative Award for the agency’s creative and innovative solution to balance motorists’ safety, while protecting wildlife and connecting ecosystems.

Hassayampa River Bridge Project

Just in time for the Fourth of July weekend, ADOT completed a $3.9 million bridge project over the Hassayampa River on I-10, approximately 40 miles west of downtown Phoenix. This area is a major route for travelers heading to and from California along I-10.

Overnight Bridge Demolition

On a late April night in southern Arizona, ADOT tore down two bridges in 10 hours – no small task. ADOT had already planned to remove the old Marsh Station bridge, which required a 67-mile overnight detour for motorists on I-10 east of Tucson. About three weeks before the demolition was set to occur, two semi trucks collided under the overpass at the Mescal Road/J-Six Ranch Road bridge. The bridge was badly damaged from the resulting fire and would have to be replaced.

Planning and Programming:

Long Range Transportation Plan

For more than two years, ADOT worked toward developing the state’s Long-Range Transportation Plan, a blueprint that looks 25 years into the future to determine how to plan for and fund transportation projects that keep up with Arizona’s needs. The State Transportation Board formally approved the Long Range Transportation Plan, also known as What Moves You Arizona, in November, allowing ADOT planners to move ahead with their work to develop a transportation system that will carry Arizona into the future. The award-winning program was nationally recognized for planning and involving the public.

Intercity Rail Study

In October, ADOT kicked off the public outreach phase of its intercity rail study. The study’s goal is to identify if there is a need for intercity rail along I-10 between Phoenix and Tucson. Over the course of a month, ADOT gathered information, data and comments. The agency will provide its findings to the public and to policymakers, so they can make an informed decision about how to move forward. ADOT is looking at all options, which include rail, transit—and the option to build nothing at all. The study will be complete in 2013.

Bicycle Safety Action Plan

As part of our public safety plan, ADOT is developing a Bicycle Safety Action Plan to help keep cyclists safe on Arizona’s highways. The goal is to reduce the number of bicycle crashes with motor vehicles and improve safety for both cyclists and drivers.  The goal of the Bicycle Safety Action Plan is to reduce the total number of bicycle crashes on Arizona highways by 12 percent by 2018.

Safe Routes to School

This year, nearly $3.5 million in grant funding was distributed by ADOT for 21 Safe Routes to School projects for schools and communities statewide. Eight of these projects, totaling $2.8 million, were designated for infrastructure improvements, such as the construction of sidewalks, crosswalks, bike lanes, signage and striping. An additional 13 projects, totaling $720,000, went toward non-infrastructure elements, such as providing bike helmets to students, safety education and law enforcement. All Safe Routes to School projects are designed to get kids walking or biking and adopt healthy habits.

Motor Vehicle Division and Enforcement and Compliance Division:

Motor Vehicle Division

MVD continued to improve the quality of customer service at MVD offices by shortening the wait times for the more common motor vehicle and driver license transactions, while serving over 3.5 million customers at MVD’s 54 offices or satellite/specialized offices in 2011 The average wait time per transaction was approximately 19 minutes, compared to over 45 minutes just five years ago. Throughout the year, MVD also provided transaction assistance to returning soldiers with the U.S. Army Intelligence Command at Fort Huachuca in southern Arizona. ADOT also launched several new specialty license plates, including the long-awaited Arizona Centennial plate.

Enforcement and Compliance Division

ADOT officers conducted Operation Bullhead, joint-agency commercial vehicle enforcement operation in Mohave County at the request of Bullhead City officials. ADOT officers recovered stolen vehicles identified during inspections. The enforcement division also created a Single Trip Overweight International Border Permit program for produce transporters out of Mexico and assisted local law enforcement with scrap metal yard investigations.

Other Accomplishments:

Grand Canyon National Park Airport

In June, the Grand Canyon National Park Airport, owned and operated by ADOT, began daily 737 airline service from McCarran International Airport in Las Vegas. Travelers can now book a flight on Vision Airlines out of Las Vegas to the Grand Canyon. The new service is the first step in a larger vision to make it easier for all tourists to visit the canyon. The Transportation Security Administration was also stationed at the airport this year, making it easier for airline companies to fly into the airport, since they no longer have to provide their own passenger screening.

Last month, as part of our Building a Freeway series, we told you about the massive underground support substructures that help give bridges strength.

Next up in the series is an important -- but temporary -- structure that’s used as crews build a bridge, tunnel or even a box culvert.

It’s called false work, and it is used to support the structure until the concrete gets its desired strength and the bridge can carry its own weight.

Imagine that you’re building a bridge out of popsicle sticks. Those sticks can’t support their own weight at first, so you might use some blocks to give it some support until your glue dries.

Those blocks are the basic equivalent to false work…

But now what happens when your bridge is complete and it’s time to take the false work out so you have a fully functioning bridge?

With the popsicle-stick scenario, pulling the blocks out might be pretty easy once your glue is dry. But with a large bridge or tunnel, it’s not so simple.

Because the false work is so tightly jammed up against the structure that it has been supporting, taking it down safely requires something called a sand-jack.

A sand-jack is a simple concept, but really is genius when you think about it …

Basically, it is a metal, square “box” (see photo below). It gets lined with plastic (to keep moisture out) and filled with sand. A ¾-inch piece of plywood goes on top of that sand and the false work is built on top.

Because the sand is contained, none of the weight is going to settle -- there’s nowhere for the sand to go.

Now, when it’s time to take the false work down, all crews have to do is unbolt the sand jack “box” and blow the sand out of it. That gives crews a few inches of “wiggle room” to pull out the false work.

To do that safely, they’ll first secure the false work with a forklift. Next they’ll carefully remove the false work structure, except for the “lid” (not a technical term, but the best word to describe this part of the false work).

The “lid” is the top, flat part of the false work over which the deck of the bridge or culvert is built. Just pulling out its support would be dangerous … so crews hold the lid up with the use of hydraulic jacks. The jacks will set on top of the concrete structure with long rods that run through the jack, through the concrete deck, and finally connecting to the false work lid. After the false work legs have been removed, the crews will slowly lower the false work lid to the ground (imagine a mechanic jacking up a car, but in reverse).

When the false work (including the lid) is all out, the bridge, tunnel or box culvert is ready to go! Check out the video above for a look at false work and sand jacks in action. The structure being built is a box culvert that will be used as an equipment pass through during construction of the Loop 303. We'll explain more about that one soon. Stay tuned...

It’s been just about six months, but today the residents of Mescal and J-Six Ranch got their bridge back and can finally say goodbye to one lengthy detour!

These two Cochise County communities had been linked together by an overpass that spanned Interstate-10. But back in March, two semi-trucks collided underneath that bridge and the resulting damage was so severe that the connection between Mescal and J-Six had to be closed for safety’s sake.

Fast-forward to today ... a brand new bridge is in place, ready to accommodate the motorists who have been forced to take the long way whenever they needed to drive between the two neighborhoods.

“For most motorists traveling I-10, this closure was an inconvenience,” says ADOT Director John Halikowski in the video above. “It meant they’d have to travel a little farther to stop for gas. But for the communities of Mescal and J-Six Ranch, the overpass closure created a heavy burden. You see, the bridge is the only road connecting Mescal and J-Six Ranch. Residents from both sides were cut off from the businesses and services they rely on.”

Normally a project like this would have taken up to two years to complete, but ADOT put this job on the fast track because of the hardship the closure caused to local residents (motorists were seeing about 14 miles added to their round trips just to get across the road, which really starts to add up after a while).

The accelerated project started with the demolition of the old, damaged bridge. ADOT was able to take advantage of a previously scheduled April 8 closure of I-10 for the demolition of the nearby Marsh Station Bridge and was able to take down the Mescal/J-Six Bridge the same night.

An expedited design timeline also helped speed things along. An abbreviated bid process that focused on contractors with a track record of building bridges under emergency circumstances kept things moving, too.

The project received $955,000 in emergency funds from the Federal Highway Administration and construction was able to get started right after Fourth of July weekend.

Work included the placement of 35 new concrete box girders atop the bridge piers. Outside support beams were also placed, but they featured attached, precast bridge barriers designed to help expedite the construction.

Amazingly, by Sept. 9, crews were already prepared to pour 150 cubic yards of concrete for the 216-foot-long bridge deck.

The concrete took 10 days to cure and you’d better believe crews didn’t let that time go to waste! They continued to work by filling gaps in the barrier wall between box girders and putting the finishing touches beneath the overpass.

The very final step taken before the bridge could open to the public included placing temporary markers along the lanes (permanent striping will be added to the roadway at a future date).

We’ve followed the progress of this project through videos and blog posts and now that the bridge is open, we hope you’ll take a look back at what it took to get here! As you can see in the video above, this bridge is important to the two communities it connects.

We at ADOT would like to thank all the residents, business operators, as well as Cochise County officials for their patience and support!

Note: This blog post was updated to reflect a revised open date for the bridge. It opened Monday afternoon, about 16 hours ahead of its Tuesday scheduled date.

The recent quake near Washington, D.C. served as a reminder that the earth occasionally moves in U.S. locales outside of California.

At ADOT, we know that Arizona is not immune to seismic activity, either. While earthquakes are far from commonplace in the Grand Canyon, our engineers take nothing for granted.

Across the state, highway and interstate bridges built since the 1970s have been designed to meet or exceed standards established by the American Association of State Highway and Transportation Officials. Older bridges have been retrofitted to help them hold up better against earthquakes.

Most of Arizona is believed to have little risk of earthquake, but certain areas – Coconino, Yuma and Cochise counties – are known to be vulnerable to seismic movement.

So when the ADOT Bridge Group set about designing the new Mescal Road/J-Six Ranch Bridge near Benson, earthquake-proofing measures were part of the plan.

That starts with enhanced reinforcement of the structure, including columns and foundation.

Each bridge is individually designed to hold up in the conditions unique to its surroundings. For instance, a location with loose sand or silt gets a deeper foundation including drilled shafts or piles.

Each bridge is built in a footprint wide enough to allow horizontal movement of the bridge. Those in potentially vulnerable areas – such as Mescal/J-Six are constructed with anchor bolts incorporated into the girders that allow controlled movement.

In the photo above, you can see the anchor bolts protruding out of the pier cap closest to the front of the picture. There is a hole at the end of each girder that goes through the anchor bolts. These bolts will allow for some movement of the girders during a seismic event, but not very much (a couple of inches laterally and less than that vertically).

You can also see the vertical fixed restrainers on the next pier cap in the photo. Those are basically cable ties that will fix the girders to that pier cap. The girders are placed on either side of the line of fixed restrainers and then a reinforced concrete diaphragm is poured in the gap, which completely ties the girders and the pier cap together. These fixed restrainers allow for no movement of the girders. The pier is permanently anchored and the rest are on the earthquake restrainers. The pier that doesn't move anchors the bridge ... the rest move and disperse any seismic activity.

Allowing for slight, limited movement during an earthquake (even a little one), means the bridges stay sound.

If you’ve been following along in the blog, you know that we’ve been chronicling ADOT’s reconstruction of the Mescal/J-Six bridge in southern Arizona since it was severely damaged when two semi trucks collided underneath it back in March. Completion of the fast-tracked bridge reconstruction is slated for later this month.

Last week, crews installed 35,000-50,000 pound girders and our video team wanted to explore a creative way to take you behind the scenes of what goes into placing a 25-ton piece of concrete.

To get the perfect shot, they looked to a GoPro® Hero. GoPros are tiny (1.6” x 2.4” x 1.2”, 3.3 oz) HD cameras that let photographers get some incredible shots they never would have been able to otherwise.

Conditions weren’t exactly ideal (check out our Facebook page for pictures of the tarantula and other creepy crawlers that joined their shoot and the extreme weather that loomed in the distance), but they couldn’t miss a chance to secure a GoPro to one of those massive girders! (You might want to sit down before watching this one…it may make you a little dizzy.)

Now that you know a little about the ADOT permitting process involved with moving oversize loads, take a look at the latest heavy haul to cross Arizona’s highways.

The video above shows just a portion of the journey this 285-ton load took beginning the first week of August.

The giant anode, which is used in the electrical process for refining copper, traveled 380 miles from its start in Salt Lake City all the way to the mining town of Miami, east of Phoenix. At 225-feet long, 20-feet wide and about 19-feet high, this oversize load was the largest to cross the new Hoover Dam Bypass Bridge ... so far!

The video shows the anode as it cautiously makes its way along SR 188 across the Theodore Roosevelt Lake Bridge. Just a few hours later and after a lot of coordination, careful planning and 14 days of slow travel (the top speed uphill was just 15 mph), the heavy load made it to its destination on schedule to the Freeport-McMohan mine in Miami!

Last week we gave you an update on how the new Mescal/J-Six bridge is coming along...

You might also remember that the night the damaged bridge was taken down, the old Marsh Station bridge was also demolished just a few miles away. It was a huge project that required completely shutting down I-10 for the night.

Check out the video above for a quick look at the work involved with tearing down two bridges in less than 10 hours.