Accommodating existing traffic is a key priority when ADOT builds a freeway …

Depending on the project, that can mean working out a construction schedule that takes rush hours into account or hiring extra crews to flag and direct traffic through the site.

But, on the Loop 303 project in the West Valley drivers will notice a new construction bypass that (amazingly) was built in around 43 hours this past weekend. The bypass will be in place for the next 10 months and not only will it allow for a more efficient way to haul dirt, but it’s also going to help drivers avoid the construction zone!

Building the bypass

Crews shut down the intersection at Greenway Road and the Loop 303 at 10 p.m. Friday, Dec. 9.

Roughly 8,000 cubic yards of dirt was hauled in from other parts of the project site to build up the road. That dirt was placed Friday night in eight-inch layers and was compacted until it was the right height for the bypass (see video above!). After that, the road was paved and striped on Saturday.

Prior to the weekend work, crews had built everything they could up until the point where the bypass would cross “live” traffic and require the closure. That required even more dirt – about 40,000 cubic yards.

Crews not only had to build the bypass, but also installed temporary concrete barriers, fencing, sidewalk and a traffic signal.

The traffic signal went in Saturday morning after the power was shut off to the “old” signal. The signal pole’s electric meter and pedestal were set to the new location and power was turned on. ADOT wired the signal Sunday morning and installed a common video detection device that will help with signal timing.

After some finishing touches, the bypass was ready and opened to traffic by about 5:15 Sunday evening – 12 hours ahead of schedule!

Before you can build a freeway, you’ve got to move a little dirt...

Make that a LOT of dirt, especially in the case of the Loop 303 project under construction right now in the West Valley.

Crews are working to construct additional lanes and plan to move about 3 million cubic yards of dirt by the time the project is finished. (By the way, a lot of work is planned for the Loop 303. The portion of the project we’re talking about runs from Mountain View Boulevard, south to Peoria Avenue.)

That much dirt translates to roughly 200,000 truck loads – and these are some big trucks (take a look at them in action in the video above).

Other projects may, or may not require this much earthwork. It depends on the road design and the original shape of the terrain.

Take the Loop 303 project for example...

Part of the freeway (starting slightly south of Greenway Road headed north) is going to be depressed ... in other words, freeway traffic will pass underneath the nearby local streets. The rest of the freeway (heading south of Greenway down to Cactus Road) is going to be elevated and will pass over local traffic.

So, parts of this project need to be dug out and other portions need to be lifted up. The dirt that crews dig out in some areas helps to build the overpasses in other spots.

If you’re lucky, it all balances out. Otherwise, purchasing additional dirt is an option. Or, if there is a surplus, the extra dirt often can be utilized in landscaping and to build berms.

Moving the dirt...

Before any digging can start, the dirt is pre-wet to make it easier to move and help with compaction and dust control.

After that, there’s some heavy-duty equipment that comes into play.

Typically, an excavator is used to dig up the dirt. The excavators being used on the 303 project have buckets that hold about seven cubic yards worth of material at a time. Those load onto something called a belly dump truck (see photo below).

Scrapers also are used to dig up the dirt. Depending on their size, scrapers can hold and transport about 14-18 cubic yards at a time.

Contractors have geotechnical reports that tell them the type of soil they’re going to be dealing with. Crews sometimes will run into rocky terrain on projects, which requires blasting.

Whether they need to blast or just dig, crews have to put the dirt somewhere...

If it’s being used on the project (as is the case with the Loop 303), the dirt is hauled to where it is needed.

It is dumped in 8-inch lifts (or layers) and is knocked down with a compactor and roller until it reaches the necessary compaction rate – again, this is where pre-wetting the dirt comes in handy.

I-10 was closed most of the day and night last Wednesday after two tanker trucks collided near Chandler Boulevard south of downtown Phoenix.

For hours, many drivers could see the resulting column of black smoke. Even more people saw footage and photos of the collision’s aftermath on the news and online.

What most didn’t see was the effort it took to reopen the freeway less than 24 hours after the fatal crash, which not only snarled traffic during the morning rush hour, but also severely damaged the road.

Timeline

ADOT’s ALERT Team arrived on the scene shortly after the 8 a.m. crash. The crew worked with other agencies to close a portion of I-10, divert traffic and create a safe location for all the emergency responders.

Even once the fire was out, work to clear the wreckage couldn’t begin for several hours because of the extremely high level of fuel vapors in the air. Once the vapors dissipated (which, with very little wind, took close to four hours), two additional tankers were brought in to remove the fuel that remained in the burned tanker.

Once the Fire Department cleared the scene, the wreckage was cleared and work could begin on repairing the road’s surface.

It was determined that repaving the badly damaged area immediately was the best way to maintain a safe, drivable surface while avoiding a future closure of the heavily traveled Interstate. Late Wednesday afternoon, ADOT worked to line up the contractors and resources needed to accomplish the repair work.

“We didn’t want to leave bad pavement for tomorrow’s morning traffic to drive on,” says ALERT Commander Tom Donithan.

By about 8:00 Wednesday evening, the section of road was milled with a machine that basically pulverizes the damaged asphalt into an “almost powder,” according to Donithan in the video above.

Once the road was milled and the old asphalt was swept away, a new layer of asphalt was put down.

Not long after that, at about 2:30 a.m., striping trucks were able to re-stripe the road and westbound I-10 between Loop 202 and Chandler Boulevard reopened to traffic at approximately 4:30 a.m.

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...

Arizona isn’t known for its harsh, winter weather conditions, but that doesn’t mean we don’t see some considerable snowfall during our colder months.

In fact, areas up in the state’s high country already had their first snowfall this season and more is on its way. So, what better time to make sure you’re ready for the winter season ahead?

ADOT certainly is ready ... as part of the department’s winter safety operations, we remove snow and ice during and after storms to keep highways open for motorists and businesses. Our snowplows are serviced and ready, our operators are prepared and our maintenance yards are stocked with deicer materials and equipment!

A few facts about snowplows and snow removal …

• ADOT has 395 employees who are trained and have commercial driver licenses, which are required to operate a snowplow.
• These employees go through a lot of training. Before they can become a certified snowplow operator, employees have to go through 4-8 hours in the classroom, 8-16 hours training in a snowplow simulator and at least 40 hours of on-the-job training.
• Snowplow operators typically work 12-hour shifts during winter storms.
• ADOT has 196 snowplow trucks in its fleet. Each snowplow costs about $250,000 and they are funded with state funds from the Highway User Revenue Fund (HURF).
• This year, ADOT is adding 15 new snowplows to its fleet. They’ll replace some of our older snowplows. (We’ll tell you more about this tomorrow!)
• ADOT is fully stocked with deicer chemicals. There are about 24,000 tons of Ice Slicer (granular product seen in video above) available statewide along with liquid magnesium chloride (a naturally occurring salt mineral).

You can see in the video above, ADOT crews are out there right in the middle of the storm, making sure the state’s roads are as safe as possible.

“Our main concern is to keep the roadways open, to keep them safe for the traveling public and to get the information out that the conditions may change as they drive,” says Flagstaff Maintenance Engineer Chuck Gillick.

While our snowplow drivers do their part to keep the roads open, motorists play a big role when it comes to safety, too …

For information on how to stay safe when driving in snowy conditions, you can visit ADOT’s “Know Snow” webpage. From maps to a look at how ADOT removes snow, the page includes some great tools you’ll want to check out.

“The main thing that drivers can do is be informed about the weather conditions and to just slow down, let the plows do their job and just have a safe ride and realize its going to take a little bit longer to get to where they’re going than under ordinary conditions,” says Gillick.

When a new highway operation technician is hired by ADOT, they’ve got one year to complete some basic training …

Part of that includes learning how to use four pieces of heavy equipment, including:

• Loaders (a heavy-duty piece of machinery that can move a lot of dirt)
• Graders (a vehicle that uses a large “blade” to create flat surfaces)
• Skid Steers (like a smaller, speedier version of a loader)
• Dump truck (used to haul large amounts of material)

In the past, training has happened in a maintenance yard. Trainees would learn by moving piles of dirt from one side of the lot to another.

The newly hired techs were definitely learning how to use the equipment, but the situation was far removed from the “real-world” conditions they’d actually experience on the job.

So, when the opportunity came about to train the new techs at a Boy Scout camp in Northern Arizona (with real roads in need of repair), it seemed like a perfect partnership!

“Our roads were so bad, people were damaging their vehicles going up and down the roads to get to the camp sites,” says Camp Geronimo Ranger Ted Julius in the video above.

Twenty new techs attended training at Camp Geronimo for the first time last month. Not only did they learn how to use the equipment, but they also were able to improve the camp’s roads by hauling dirt, grading roads, cutting ditches and putting in culverts for drainage.

ADOT Phoenix Maintenance District Engineer Tim Wolfe estimates that ADOT saved $10,000-20,000 in training expenses.

But, the benefit wasn’t just financial …

“Because of this training, our new hires are much more confident and better trained,” said Wolfe, adding this training academy worked so well, another is tentatively planned for next spring.

Wolfe says the main focus of the training is on safety. Learning in a controlled environment means the techs will be more familiar with the equipment before working on the side of the state’s highways.

“These guys are coming away more comfortable with the equipment and that means they’ll produce better roads,” he said. “This is a benefit to ADOT, a benefit to the scouts, and a benefit to the tax payers of Arizona.”

You know when you drive under or over a freeway bridge that it’s a massive structure…

There are the two abutments (the upright supporting structures at each end that carries the load of the bridge span), there are usually center columns or piers, and, of course, the girders and the bridge deck (the part you actually drive across).

The girders and the deck make up the bridge’s superstructure. (You can tell how much goes into a bridge’s superstructure by checking out what goes into taking one down.)

But what you don’t see is that buried beneath the bridge is part of the equally impressive substructure formed by rows of caissons – massive steel-and-concrete pillars that support and lock in place the abutments.

The substructure, which is made up of the caissons and the abutments, ensures that the bridge is secure and strong enough to support not only its own weight, but also the weight of all the vehicles that drive across it every day.

The caissons are formed by tying thousands of feet of rebar into massive steel cages that are then lifted with a crane, lowered into drilled shafts, and filled with concrete. Several feet of rebar is left rising out of the ground, which is what the abutments are ultimately secured to.

There’s no such thing as a “standard size” caisson…their lengths and diameters vary from project to project and bridge to bridge based on several factors, including the soil type and the expected and actual weights the bridge must support.

Generally speaking, caissons for most bridges in Arizona are between 40 and 120 feet deep and 5 to 12 feet in diameter.

There’s also no set number for how many caissons each abutment will require – that, too varies by bridge.

Take the three bridges being constructed for the new phase of Loop 303 in Surprise, for example. The bridge abutments at Waddell and Cactus roads are supported by 23 caissons each (46 total per bridge), while the bridge at Greenway Road, which is only partially elevated over Loop 303, requires just 20 total caissons (10 under each abutment).

The video above shows the fabrication and installation of those Loop 303 caissons. The steel cages for these particular caissons are 95-feet long and weigh about 20,000 pounds. The cages were lowered into 88-feet-deep drilled shafts and filled with 80 cubic yards (8 truckloads) of concrete each.

If you’re keeping tally…that’s 8 truckloads for each caisson, times 106 caissons, for a total of 848 cement truckloads (for just those three bridges)…and that is just part of the substructure!

The concrete for these caissons cures in about 24 hours, clearing the way for the next phase of building a freeway.

According to estimates, nearly 2.5 million vehicles pass through the very small town of Tusayan, Arizona each year…

So, where’s everybody going?

They're typically headed to one of the country’s biggest tourist destinations -- the Grand Canyon.

One of the main routes to the popular south entrance happens to be State Route 64, which takes motorists right through the middle of Tusayan (pop. 560).

The small town gets a lot of pedestrian and vehicle traffic and understandably there have been some concern related to all the activity on SR 64.

The roadway consists of four lanes and has one two-way left-turn lane. Hotels, restaurants and shops line the highway, which has no crosswalks or traffic signals. Pedestrians sometimes cross the highway at random locations, which has raised some of the concern.

After Tusayan officials asked ADOT to study the highway, it was concluded that making design changes would enhance the safety and appearance of the roadway.

ADOT is investing $4.1 million to widen the roadway in order to install a raised median, which will allow pedestrians to cross the street more safely.

In addition, two roundabout intersections will be constructed at the beginning and end of town and bus bays will be added.

The roadway improvements, aesthetic enhancements and new lighting are designed to create a more welcoming entrance to the community and encourage more people to stop and enjoy the community and the services it has to offer.

Town Manager Enrique Medina Ochoa believes the project could help his town.

“Studies that they’ve done have shown that the majority of the people going to the Grand Canyon will spend maybe 4.1-4.5 hours. Then they come out and maybe they’ll have lunch or breakfast or dinner there in Tusayan and see a few things,” he says in the video above. “We’re trying to change it so that people will be able to stay and I think the ADOT project, the enhancement beautification and safety project will really help.”

Construction began in July and the project is expected to wrap up by next summer.

Construction got started earlier this fall on a project that’s designed to bring some big improvements for a stretch of Interstate-10 in the Tucson area.

The I-10 widening project from Ruthrauff Road to Prince Road will not only expand the freeway to four lanes in each direction, but will also reconstruct the Prince Road traffic interchange so the road will pass over the Union Pacific Railroad tracks and I-10. New landscaping and entrance and exit ramp improvements are also part of the plan.

Right now traffic delays at the Prince Road/I-10 intersection are a frequent occurrence ... that’s because more than 40 trains pass through each day. This often causes traffic to back up onto nearby I-10. (Union Pacific Railroad plans to double the tracks in the near future; so many more trains are expected to pass through the intersection in years to come.)

Tucson District Engineer Todd Emery says in the video above that the plans to lower I-10 and bring Prince Road over the railroad and freeway will help alleviate the daily traffic jams.

Here are some basics on what you should know for this first phase of the project (as of Oct. 3):

• Full access to all area businesses will be maintained throughout construction.
• Prince Road is closed west of I-10.
• Riverpark Drive, La Cholla Boulevard and Business Center Drive just west of I-10 at Prince Road are closed; however easy access to businesses and organizations on the west side of I-10 is possible by exiting I-10 at the Camino Del Cerro/Ruthrauff Road traffic interchange and using the eastbound frontage road.
• The I-10 frontage road south of Prince Road will be accessible during construction.
• Both the nearby I-10 Miracle Mile and I-10 Camino DelCerro/Ruthrauff Road traffic interchanges will remain open throughout construction.

Construction is scheduled to last about 26 months, so stay tuned. We’ll keep you updated on what to expect during the next phase of construction, slated to begin in fall 2012.

Several miles of new HOV lanes opened earlier this week in Chandler and the West Valley … just in time for the Monday morning commute!

ADOT opened the new stretches of High Occupancy Vehicle lanes along the Loop 202 Santan Freeway in Chandler and the Loop 101 Agua Fria Freeway in the Glendale and Peoria area.

The completion of the new eastbound Loop 202 carpool lane east of I-10 marks the end of an $84.7 million project to add 12 miles of HOV lanes in each direction between I-10 and Gilbert Road in Chandler . That project, which started in September 2010, included the addition of elevated HOV lane ramps that provide carpoolers with direct connections between Loop 202 and the Loop 101 Price Freeway as well as I-10.

Along the Loop 101, crews opened a 12-mile stretch of the new westbound and southbound HOV lane between 51st Avenue and Glendale Avenue. ADOT is adding 30 miles of new carpool lanes in each direction along Loop 101 between State Route 51 in north Phoenix and I-10 in the West Valley . Work on that $90 million project began in January of this year. Sections of the new lanes have been opened in stages as the project advances. The plan is to open another segment Monday morning. After this weekend, the entire stretch of HOV lane (heading west to south) from SR 51 to Thomas Road will be open. All the carpool lanes are scheduled to be open to traffic by next month (November).