It might not look like much, but the Lowell Arch Bridge is a very important piece of Arizona's highway history.

In 1910, the Arizona Territorial Engineer's office completed the design and survey for the Bisbee-Douglas Highway, a 22.7-mile highway between ... well, the name says it all. This road was a vital link between the copper mines of Bisbee and the Phelps-Dodge smelter in Douglas. Indeed, it was the most expensive road project the Arizona Territorial Assembly had ever approved, costing nearly $78,000 at the time.

And the most important crossing on the highway was the Lowell Arch Bridge, a 60-foot-span, 16-foot-wide roadway over Mule Gulch, about six miles east of Bisbee. The contract for the bridge and that section of highway was awarded in October 1910 to the company R. Toohey and Sons out of Phoenix. The firm completed the work in December 1911, producing a bridge that featured more than 156 cubic yards of concrete, with an elliptical arch made from reinforced concrete abutments and guardrails.

In coming decades the Bisbee-Douglas Highway would become part of US 80, the important southern cross-country route that ran between Savannah, Georgia and San Diego. Though US 80 itself would be decommissioned in the late 1980s, this section still remains part of the state highway system as State Route 80.

The only alterations made to the Lowell Arch bridge since its original construction came in 1934, with the widening project on US 80. The work, completed for just under $36,000 widened the bridge considerably, as well as extending the abutments and wingwalls. Since then, the bridge continues to carry traffic on SR 80 with no further alterations.

The Lowell Arch Bridge not only played a very important role in Arizona's copper-mining industry, it was one of just two concrete arch bridges built by the Territorial Engineer (the other, in Tempe, is gone). And, unlike some other historical bridges we've featured on this blog, its still one that you can drive across today as part of a state highway.

If that isn't excuse enough to drive between Bisbee and Douglas, we don't know what is. 

When it’s halftime in a football game, the teams can use the break to go over strategy for the second half action. But on ADOT’s project to reconstruct the Interstate 17 bridge over Central Avenue, crews didn’t get much of a break before their own second half got underway.

Of course, the strategy was already known. The project team is using “construction in stages” to build the new steel-girder freeway bridge, which will be wider and provide additional clearance for Central Avenue traffic traveling under it. 

The project’s “first half” included a temporary switch of all I-17 traffic onto the existing northbound side of the bridge so crews could tear down the southbound half and build a new span in its place. That work wrapped up in February, allowing crews to use the weekend of Feb. 20-21 to switch freeway traffic to that new southbound span (with two lanes in each direction).

Just one week later (this past weekend of Feb. 27-28), it was time to demolish the old northbound structure. That feat was accomplished with heavy equipment that pounded away and pulled at the girders, the concrete and other material in time to reopen Central Avenue for Monday morning travel.

Now the project team will start the march toward the goal line. They will build the new northbound half of the I-17 bridge south of the downtown Phoenix area. Completion is scheduled for this fall. At that time northbound traffic will be switched to its rightful place with more room to operate.

The I-17 bridge will be wider to accommodate regional plans to add more lanes in the future, including auxiliary lanes (also known as merge lanes) between interchanges along the freeway in that area, including Seventh Street and Seventh Avenue.

The improved bridge also will provide more clearance for Central Avenue, not just for larger commercial trucks but also for Valley Metro’s light rail line that also will be passing under I-17.

So I’ll raise my sports drink bottle to the crews on the I-17 bridge project and wish them good luck in the second half. Here’s hoping they give us a game winning drive. Pardon the pun.

We love engineers!

But do you know that there are many different types of engineers? Just at ADOT we have many different kinds who look at everything from the best way to get cars over a bridge to the water and power lines that go underground. 

If you've ever thought about being an engineer, here are some of the options available to you!

And once you have read about all the different types of engineers, click on the photo to have your parents download our seek-and-find activity to match them with the type of work they do!

Civil Engineers:

If you’ve got the inclination to draw, design, problem solve and create order, you might want to be a civil engineer. Civil engineers uses computer-aided design and drafting to prepare the technical drawings used to build freeways, bridges, and more. Civil engineering deals with the design, construction, and maintenance of the physical and naturally built environment. This includes public works such as roads, bridges, canals, dams, airports, sewage systems, pipelines as well as structural components of buildings and railways.

ADOT has many specific kinds of civil engineers. These include:

• Geotechnical engineers, whose knowledge of soils and rocks are important to building roads and bridges.
• Drainage engineers with expertise in designing for flooding and erosion control.
• Environmental engineers with expertise in minimizing the negative impacts to the environment while constructing and maintaining transportation features.

Civil engineering also includes what we are going to look at next: roadway, traffic and bridge engineers. 

Roadway, Bridge and Traffic Engineers:

Roadway, Bridge and Traffic engineers use mathematics and science to determine where or how to build new highways and to make existing highways better.

• Roadway engineers work with many other types of engineers and together they make plans for construction to make the highways. Roadway engineers design the geometric parts of a road such as widths, curves and slopes.  They also design road safety hardware like guardrails.
• Bridge engineers use computer programs to design the bridges that carry cars and trucks over waterways, rivers, washes, railroads and other roadways.  
• Traffic engineers design the signs, pavement markings and roadway lighting that help make the highways safe to drive on and help people understand where they need to go. They also design traffic control plans used to help traffic move safely through a work zone.

Resident Engineers:

Resident engineers work in ADOT district offices around the state and make sure contractors who build the projects follow the design plans. They also help resolve challenges and find solutions while the project is being constructed.

Survey Engineers and Surveyors:

Before a designer can prepare construction plans for highways, roads and bridges, they need more information about the land they wish to build on.

• Surveyors use tools to measure and locate features like mountains and rivers that can be used to make topographic maps. Topographic maps detail the “topography” of the land, showing the surface of the earth and features such as hills, rivers and houses. These maps and plans help engineers design highways and bridges. Aerial photography is done by planes or drones taking pictures from the sky. Did you know that George Washington was a surveyor?
• Survey engineers and surveyors provide engineering surveys and topographic maps to assist designers of ADOT highway projects. They collect and analyze 3-D information about the land, roads and bridges. They use sophisticated equipment such as Global Positioning Systems (GPS), levels and electronic theodolites. Theodolites are special telescopes that help them measure angles while surveying. They then use computers to make 3-D digital drawings for other engineers to use while designing highways. Survey engineers and surveyors also help ADOT’s Right of Way group by performing property surveys. 

Transportation technology engineers:

Transportation technology engineers use computers, electronics, control systems (like traffic lights), communications technologies and management strategies for transportation systems to provide travel information to improve road safety and efficiency. As new transportation technologies emerge, like self-driving vehicles and smart/connected cars, transportation technology engineers are needed to make sure our infrastructure safely accommodates these new transportation trends.

Have you seen the message boards along the freeway? These are types of transportation technology. Technology is also used to calculate the travel times displayed on the boards like how long it will take to get from Phoenix to Tucson based on distance and how fast cars are traveling. If there is a crash on a road and a lane is closed, it will take much longer to get to Tucson from Phoenix. 

Utility and railroad engineers:

Utility and railroad engineers work with utility companies and design engineers to locate underground utilities. Did you know that things like the water, electricity and gas that come into your house are called “utilities?” The pipes and wires that bring these utilities are located underground or strung from large poles. Utility engineers help place all these pipes and wires under the ground or on poles.

When highway projects are happening, utility engineers help locate these utilities and other items that could interfere with construction. They use non-invasive technology and techniques along with carefully controlled excavation methods to provide detailed information on underground features so they can either be avoided or relocated. This process is important to construction workers’ safety, controlling costs and making sure people nearby can still have water and electricity.

ADOT does not have engineers that drive trains but they have engineers to determine what to do when a road and a railroad meet at a crossing or when a bridge goes over or under a railroad. To ensure that trains and cars can travel safely while sometimes crossing paths, utility and railroad engineers ensure the safety of motorists and train operators by using signs, signals and pavement markings.

Engineer as a career

There you have it! There are so many different types of engineers you can grow up to be. But all of them are important in designing and building highways and bridges, not to mention keeping people safe. 

While deciding what kind of engineer you want to be, have fun with the seek-and-find activity! And if you are really interested in being an "engineer-as-a-career," watch for more ADOT Kids videos, blogs and activities running this week for National Engineers Week. And make sure to check out the ADOT Kids website or find #ADOTKids on social media!

Designing bridges and roads. Surveying land and streams. Improving road safety. Maintaining existing transportation infrastructure. These responsibilities and more reflect the work our engineers perform daily at the Arizona Department of Transportation. Whether you are a bridge, civil, roadway, survey, traffic or transportation technology engineer, your work matters and makes a difference in the communities we serve. Therefore, I am proud to recognize our engineers for National Engineers Week, Feb. 21-27, under the theme “Inspiring Wonder.”

Building a safe and efficient transportation system requires the skills of many talented engineers and support staff. It takes knowledge and teamwork to design and operate a state transportation system. I see the accomplishments our engineers achieve every day. It is especially rewarding when our teams are recognized, both locally and nationally, for projects that serve the traveling public. Examples are the wrong-way driver detection and dust storm detection systems, and the one-year-old Loop 202 South Mountain Freeway.

Having the right skill set to build bridges and roads, and implement safety measures requires an interest in STEM (Science, Technology, Engineering, Math) education. It is never too early to pique the interest of children in the field of engineering and inspire a world of wonder.

Our national award-winning ADOT Kids program is an example of teamwork and the work of our engineers. We created ADOT Kids in an effort to educate children about transportation and to keep it fun. From learning how snowplows operate, to building a bridge and decorating our roadways with unique designs, to creating highway safety messages and Keeping Arizona Grand, ADOT Kids has been a huge hit with children, parents and educators. Our ADOT engineers and employees have enlightened the community by serving as subject matter experts in answering questions from children.

I have the most deep respect for the engineering community. I congratulate our engineers on this special week of recognition. They do indeed inspire wonder in our communities and are worthy of us saying ‘thank you’ for the work they do.

Today, determining jurisdiction is pretty simple. ADOT oversees all state highways and freeways, with individual counties and municipalities taking care of the local infrastructure that falls inside their boundaries. But in the early days of transportation, such things were still being worked out.

And that brings us to the Leslie Creek Bridge. Located along Leslie Canyon Road in Cochise County roughly 17 miles north of State Route 80 near Douglas, this bridge is going on 93 years and is listed on our inventory of historic bridges in the county. 

The origins of this 70-foot bridge goes back to 1928, when the Cochise County Board of Supervisors approved its construction. Chosen to make the parts that would eventually become the Leslie Creek Bridge was the Virginia Bridge & Iron Company, which made bridges across the country during this time. For this particular location, a truss comprised of 10 equal-length panels, with verticals at the panel points, was made. These fabricated parts were then shipped to Arizona via rail in May 1928. Construction got going almost immediatley using prison labor, which wasn't that uncommon at the time. The bridge was done by the end of that summer and has been functioning since. It was also a fairly common design for the times. In fact, the Leslie Creek Bridge is one of eight in the inventory with virtually the same structure. 

That's all well and good, you might say, but this is an ADOT blog, so why are we talking about a county bridge nowhere near a state highway?

Because the Leslie Creek Bridge was built at an unusual time. In the late 19th and early 20th centuries, local governments often took lead in establishing roads, bridges and other infrastructure. By the time the span over Leslie Creek was done, the Arizona Highway Department - the precursor to ADOT - had taken over the main responsibility for building bridges statewide. However, individual counties would still sometimes do smaller projects just as they always had. This particular bridge is one of the later examples of a county-built bridge, purchased in prefabricated parts from a national bridge company, and constructed by local crews.

And, hey, it seemed to work. Having a bridge just shy of a century is pretty impressive, no matter the size or where it's located!

Arizona’s mountainous terrain is as beautiful to look at as it is to drive through, but keeping dirt from those slopes off roadways can pose a technical challenge.  

That’s one reason the Arizona Department of Transportation has deployed highly sophisticated measuring equipment on embankments across the state.

On a recent trip to State Route 87 between mileposts 224 and 225 south of Payson, ADOT Geologist James Lemmon and Engineer-in-Training Ivan Bystov inspected two examples of this technology. The hill they're working on is part of a decade-old landslide known as the Sunflower Landslide.  

Lemmon and Bystov hiked along a ridge on the east side of the highway toward what looked like a yellow chimney sticking out of the hillside. In fact, the yellow riser is a steel casing to protect the inclinometer pipe and the piezometer equipment inside the well.  

The inclinometer enables scientists like Lemmon and Bystrov to measure the rate of slope movement over time.

“We are trying to see if there is a change or any instability,” said Lemmon, an ADOT Geotechnical Design Section-Bridge Group member.

The information is used to take preventive action if the hill is moving down a slope toward the roadway.  

“We know we must do something to buttress it to keep it from moving,” Lemmon said.

Lemmon said there are about 130 individual inclinometer wells installed at 30 embankment sites around the state. Sunflower Landslide has over 20 active inclinometers that are read on a regular basis. Some are on the roadway surface, many are on the near slopes and several are near the very top of the steep road cutouts and mountain slopes.

The piezometer measures moisture and saturation levels.

"When designing and constructing bridge foundations, we need to know the depth of where the saturated water level is under the surface so construction equipment doesn't sink and disappear into the saturated earth, Lemmon said. "And we design the foundation for a saturated groundwater situation. Those depths to water are measured by the piezometers."

The piezometer Lemmon and Bystrov displayed goes down about 60 feet deep, but Lemmon said there locations on the Sunflower Landslide where they go down nearly 400 feet deep.

We’ve been sharing plans for a new and much wider Houghton Road bridge at Interstate 10 in Tucson for some time now, but we know it may have been hard to picture exactly what we’ve been talking about.

No more. Take a look at this aerial shot and you can see the new bridge is wide - even wider than the interstate below.

This photo from early January shows only the girders of the new bridge, as it doesn’t have the concrete deck on top of it yet. Once the deck is completed later this year, it will accommodate six lanes of traffic rather than the two lanes on the existing structure. It’s all part of a $24.4 million interchange replacement project to improve safety and traffic flow in this rapidly growing area southeast of downtown Tucson.

You probably also spotted that the photo shows sections of concrete that will form the new ramps. They’re being built in stages, so drivers should expect periodic changes as traffic is gradually shifted onto larger sections of the new ramps through the rest of 2021. Through the rest of the project, occasional nighttime closures are possible on the ramps as well as on Houghton Road.

However, drivers should expect periodic overnight lane restrictions on I-10, including this week. Each weeknight, crews will reroute one direction of I-10 up and over the entrance and exit ramps. The other direction of I-10 will be reduced to a single lane. Houghton Road will remain open, but expect delays of up to 15 minutes. The work is scheduled from 9:30 p.m. to 5:30 a.m. as crews work on bridge piers and abutments.

Drivers can expect to take advantage of the new bridge and ramps by the end of 2021. 

And a reminder: The Houghton Road interchange will be the first diverging diamond interchange in southern Arizona. To learn more about that kind of interchange or the project as a whole, please visit azdot.gov/i10Houghton.