EDITOR'S NOTE: During this unprecedented time, ADOT is creating transportation activities for kids. Please visit azdot.gov/ADOTKids or use the hashtag #ADOTKids on ADOT's Twitter, Facebook and Instagram accounts to see what we have going on. 

By Garin Groff / ADOT Communications

We’re excited that so many kids wanted to learn more about bridges and also that so many of you shared your bridge drawings with us!

We’ve already explained some of the work that goes into designing, building and maintaining bridges, and then we asked you to share questions you have about bridges. And you had lots of great questions! The video at right has answers from David Benton, ADOT’s bridge design manager. And here are some others, also with Mr. Benton's help: 

What is the longest bridge in Arizona?

While the video highlights the Mile-Long Bridge on Loop 202 in Tempe (a mile is 5,280 feet), after this activity ended we realized there's an even longer one. An elevated section of Interstate 10 near the "Stack" interchange with Interstate 17, just west of downtown Phoenix, is 7,111 feet long, making it the longest bridge in Arizona. Those are two very long bridges!  

How do bridges withstand earthquakes?

You might be surprised by this, but bridges can be built to move and wiggle like a spring when an earthquake hits. This allows the bridge to move along with the earthquake so the bridge parts don’t get damaged. And if they do get damaged, those parts can be fixed and the bridge can still stand.

How do you fix the parts of a bridge that are underwater if they break?

Fixing bridge parts underwater is tricky. In most cases, the best way to fix a bridge part that is underwater is to pump the water away so the construction workers can get to it and make repairs.

Why are triangles strong?

Triangles are strong when you put them together with a lot of other triangles. The reason they can be so strong is because some of the three sides of that triangle can be pushed and pulled. When those sides work together as a team, they can take a lot of weight. Check out how to build a popsicle stick bridge on the internet and you can find out ways to build these triangles!

Thanks again for all these great questions. Now let’s look at everyone’s great artwork!

EDITOR'S NOTE: During this unprecedented time, ADOT is creating transportation activities for kids. Please visit azdot.gov/ADOTKids or use the hashtag #ADOTKids on ADOT's Twitter, Facebook and Instagram accounts to see what we have going on. 

EDITOR'S NOTE: During this unprecedented time, ADOT is creating transportation activities for kids. Please visit azdot.gov/ADOTKids or use the hashtag #ADOTKids on ADOT's Twitter, Facebook and Instagram accounts to see what we have going on. 

By Garin Groff / ADOT Communications

Do you like building things? How about rock climbing? Or flying drones? If any of those things sound fun to you, then you might enjoy becoming somebody who designs and builds bridges.

Bridges are an important part of helping people get around your town and to other parts of Arizona. Think of all the times you cross bridges. They go over rivers, washes, canals, railroad tracks and even other roads – they can be just about anywhere!

It’s really cool to watch bridges being built. Just take a look at this video to the right and you can see a 2016 ADOT bridge project on Interstate 15 in the northwestern corner of Arizona.

What does it take to build a bridge? First, you need people who have studied a lot of math and science. When they learn certain types of math and science, they can become engineers – people who design and build things.

After engineers design a bridge, construction begins. Workers drill holes up to 100 feet into the ground for the foundation, then fill the holes with concrete and steel. On top of that, more concrete and steel are used to make piers. Then on top of the piers, huge cranes lift large metal or concrete sections called girders. Finally, concrete is poured on top of the girders for the roadway.

All that work usually takes 9-12 months.

After bridges are built, workers sometimes need to inspect bridges to make sure they are well-maintained. It’s not easy getting to all the places underneath a bridge, but some of the ways to get there seem fun! Some workers rappel off the sides of bridges like rock climbers. And sometimes, we fly drones to look under bridges.

Bridges are built strong enough to last 75 years but can last even longer with good maintenance. When it is time to replace and tear down a bridge, you might be surprised at one way to do it – with explosives! Check out this video of the 2016 Hell Canyon Bridge demolition north of Prescott to see how fast a bridge can be demolished. 

I hope you know a lot more about bridges now. And I want to tell you about ADOT’s bridge design manager, David Benton. He is a civil engineer, a person who designs things like bridges, roads, dams or airports. He first thought about construction and engineering when he spent a lot of time playing in the mud as a kid.

“If you like to build things out of mud and like to shape things out of mud, that’s what it’s like to build with concrete,” he said. “I remember a teacher said if you like to build things and you’re good at math, civil engineering is a good profession.”

Mr. Benton has kindly volunteered to answer questions you send us about bridges when you complete this week's ADOT Kids activity:

DRAW A BRIDGE AND SEND IT TO US: We've provided a coloring sheet below with a highway that needs a bridge to be complete. When you draw your bridge, have an adult scan or take a picture of your drawing and email it to [email protected]. If you don't have a printer handy, feel free to create your own bridge drawing from scratch and share it with us. NOTE: We've included a slideshow below with all pictures that were sent to us. 

To provide inspiration, we've included a slideshow below with pictures of bridges so you can see the creative ways engineers design how to support them. As you look through the photos, think about how you will support your own bridge.

We'll add every drawing we receive by 5 p.m. Wednesday, April 29, to a slideshow and put it right here on Friday, May 1, so you can see your masterpiece along with everyone else's. We've included spaces for you to include your first name (only your first name, please), your age and where you live. We can't post photos of you with your art, but we'd love to show just your art.

SEND US QUESTIONS: When an adult emails your picture to [email protected], please send us questions you have about bridges. We'll share the most popular questions with Mr. Benton, the ADOT engineer who knows A LOT about bridges. NOTE: We've included a video below with Mr. Benton's answers. 

I can't wait to see what you do with these drawings and to see what questions you have about ADOT bridges!

Slideshow with examples of bridges:

The coloring activity sheet:

Video answering your questions:

Slideshow with everyone's colorings:

Since an eastbound Interstate 10 bridge started carrying traffic over Ruthrauff Road in 1965, the number of vehicles that have traveled this northwestern Tucson locale is impossible to calculate.

But once crews began demolishing the structure this week, we can count exactly how much time it took to reduce the bridge’s surface into concrete rubble and twisted rebar: two days.

This Flickr album of the demolition work shows the rapid progress we’re making to rebuild I-10/Ruthrauff Road interchange only two months after starting the $129 million project.

As for the remaining parts of the bridge, they’ll also be history by the end of the week.

If you’re wondering how I-10 traffic can keep flowing with one of two bridges now gone at Ruthrauff Road, here’s the solution ADOT’s project team has in place: Westbound I-10 traffic is now getting through the work zone on the westbound frontage road, while eastbound I-10 traffic has been shifted to the old westbound lanes.

Some temporary sections of pavement allow three lanes of traffic to flow in each direction. And we’re maintaining access to all businesses with other temporary changes to the frontage roads.

The demolition work is just one of many dramatic changes drivers will see until the I-10/Ruthrauff Road project is completed in late 2021. Stay tuned for more photos and other updates.

Traffic is coming to a stop at times on State Route 77 in Winkelman, but it’s for a good reason: Things are moving forward on a project to replace the bridge over the Gila River.

Work began Monday to hoist bridge girders into place as crews continue rebuilding the first half of the new structure. Placing each girder requires two cranes – one on the existing half of the bridge and another in the river bottom – and a full closure of the highway for 15-20 minutes.

Drivers should expect three to six of these brief closures Mondays through Thursdays over the next 10 days or so.

The Gila River bridge reconstruction is scheduled through summer 2021. To learn more, please visit the project website.

Drivers in Tucson will notice many changes and upgrades to Interstate 19 between Ajo Way and Irvington Road. But something they can't see from behind the wheel is a big step-up for those living near the freeway.

The newly constructed Michigan Street Pedestrian Bridge over I-19 features new ramps that comply with the Americans with Disabilities Act. The bridge was installed in mid-January to connect city neighborhoods on either side of the freeway. It replaced the old pedestrian bridge, which was not ADA compliant because it had stairs and no ramps.

“The new bridge is well lit, has ramps that comply with the Americans With Disabilities Act, and it is more aesthetically pleasing due to its artwork and more modern design,” said Senior Resident Engineer Chris Page.

You can see for yourself that "aesthestically pleasing" part in the slideshow to the right from our Flickr page.

The pedestrian bridge is part of the $84 million I-19/Ajo Way traffic interchange project, which is in the second of two construction phases.

Other work includes

• constructing a braided ramp alignment — first of its kind in southern Arizona — connecting Ajo Way with I-19 separately from the I-19 traffic exiting at Irvington Road.   
• reconstructing and widening southbound I-19 within the project area.
• widening northbound I-19 to add an auxiliary lane between Irvington Road and Ajo Way.
• completing I-19 noise walls south of Michigan Avenue and along the south side of Ajo Way between Kostka Avenue and I-19.
• completing drainage improvements and improving drainage collection features.
• replacing the Michigan Avenue pedestrian bridge.
• replacing the Santa Cruz River Bridge on Ajo Way.
• constructing bank protection and the new Rodeo Wash outlet into the Santa Cruz River.
• reconstructing and widening Ajo Way from Holiday Isle to I-19.

The first phase included a new traffic interchange at Ajo Way and I-19, major drainage improvements, sound walls, utility relocation and an upgraded traffic light at 16th Avenue.

You may be familiar with the various bridges across the state highway system. Maybe you drive over some every day as you commute to and from work. But how often have you been afforded a glimpse of that start of a bridge from the bottom of whatever depression, river bottom, ditch, hole or canyon it's trying to cross? 

That's what we wanted to show you here. This photo was taken in July 1964 at Burro Creek. And, looking up, you can see the very beginning of the bridge that would carry US 93 over the creek between Nothing and Wikieup.

Arizona had decided to bring what was then State Route 93 south from the Nevada state line to Wickenburg to better accommodate travel between Phoenix and Las Vegas. This particular steel arch bridge was designed by veteran state highway department engineer Ralph Hoffman. Early in his career, Hoffman had also helped design Navajo Bridge, which spans the Colorado River at Marble Canyon. 

We can't speak for you, but just looking at that staircase desending from the top all the way down to where the bottom foundations are is giving us a slight sense of vertigo. 

The bridge would finally be complete and dedicated in 1966, marking it as one of the few projects during that time not directly related to the construction of an interstate. 

But times changed, and by the late 1990s ADOT saw the need to widen US 93 to accommodate even more traffic between Phoenix and Las Vegas. One of the first areas to be improved included Burro Creek. A twin bridge, finished in 2008, was constructed next to the original to help handle the increased traffic.

While driving across a bridge helps give you a sense of how much work went into constructing it, sometimes you can only appreciate the sheer magnitude of a thing by looking at it from the bottom up.

Driving along US 60 at Pinto Creek, motorists see heavy equipment carving a road out of the rocky terrain at what might seem like a slow pace.

But when the highway is closed to the public, progress comes in bursts.

Just take a look at how quickly explosives dislodge rock in this video captured by ADOT’s video team. The blasting is the most dramatic part of a two-year project to replace the Pinto Creek Bridge, which requires carving an access road into the canyon so crews construct bridge piers.

The blasting has been underway for several weeks, when crews close the highway twice a week between Superior and Miami to keep the public at a safe distance. Blasting will continue Tuesdays and Thursdays, from 9 a.m. to 1 p.m., into December.

The explosives are used on rock that’s too hard to be removed by earthmoving equipment. But construction also occurs on weekdays, when crews remove softer rock, continue building the access road and prepare for the next blasting operation.

Drivers in the area should expect lane restrictions and allow for extra travel time. Keep up to date on scheduled restrictions or closures at azdot.gov/PintoCreekBridge.

While the electric slide enjoyed the height of its popularity in the 1990s, ADOT and its contractor for the Bellemont bridge project, Fisher Industries, are introducing the bridge slide as an innovative method for accelerated bridge construction.

The bridge slide method, which we detailed recently in a news release, involves pre-casting new bridges right next to the existing bridges. The old bridges are then demolished and new bridges are lifted and “slid” into place using hydraulic jacks. This process took less four-and-a-half days to accomplish on the Bellemont project once the new bridges were built.

This method was proposed by Fisher Industries through a process called value engineering where the plans of a project are analyzed looking for ways to improve quality and value while reducing time needed to complete the work.

This bridge-sliding method takes months off of construction time compared to the traditional way of building new bridges while maintaining traffic through the area. The residents and those who travel through Bellemont are spared months of lane closures and restrictions thanks to this innovative method.

Check out the time-lapse video taken by ADOT’s video team to see how the bridge-slide method works.