The Arizona Department of Transportation (ADOT) is investing $70 million to replace two aging bridges on U.S. 60 just east of the town of Superior in Pinal County.
Construction began in early 2024, with Ames Construction expected to deliver the project in the summer of 2028.
Ames has crews working on the two new structures between mileposts 227 and 229.5.
A new Queen Creek Bridge is being constructed just east of the existing steel arch bridge — 763 ft. long, one lane in each direction plus shoulders — which will be demolished once the new one is built.
Ames Construction photo
The concrete Waterfall Canyon Bridge, supported by several concrete columns — 107 ft. long, one lane in each direction, east of the Queen Creek Tunnel — is being reconstructed into two box culverts to improve drainage, and will remain in its existing location. Guardrail replacement and other general maintenance work also is occurring within and near the Queen Creek Tunnel.
"The Queen Creek Bridge, built in 1949, and the Waterfall Canyon Bridge, built in 1929, were built to standards in those times," the ADOT project web page said. "However, those standards no longer meet the current minimum bridge guidelines of ADOT or the Federal Highway Administration and the American Association of State Highway Transportation Officials. ADOT has completed multiple maintenance projects on the bridges to extend their lives; however, due to weather and continued traffic-induced vibrations, the structures have reached the end of their useful lives."
"[The bridges] provide access from Globe and eastern Arizona to mines in Miami and Superior," Garin Groff, an ADOT spokesman, told Construction Equipment Guide. "Regionally, it reduces the detour through Winkleman by approximately 75 miles."
The project's scoping document was completed in 2017. An in-house ADOT team designed the project.
In 2023, 8,242 cars and trucks crossed the bridges daily. By 2043, ADOT estimates the daily traffic count will increase to 14,754.
"The main challenges were the rock blasting and removal from U.S. 60 to maintain traffic," said Groff, "as well as the access road to build the bridge, the removal of the existing bridge and geotechnical conditions."
The lifespan of the new bridge structures is 75 years.
Ames Construction photo
The traffic management plan is based on occasional restrictions and closures of U.S. 60 in the work zone during certain types of work, such as rock blasting.
Ames Construction has completed the corridor safety improvements. Over the next year, efforts will focus on completing the new bridge substructure and beginning — and hopefully completing — the new bridge superstructure.
The project has encountered a range of geological challenges.
"The team continues to assess these conditions and implement effective, engineered solutions to address each issue as they arise," Zachary Taylor, Ames Construction's senior project manager, told Construction Equipment Guide. "While the project has involved numerous challenges and unknown conditions, the team has worked diligently to overcome them. Progress continues steadily, with work advancing as efficiently as possible given the site conditions."
"Despite the challenges inherent in the project, coordination and collaboration with ADOT have remained strong," he added. "The Ames project team and ADOT communicate proactively and work together to resolve issues efficiently, maintaining a positive and productive partnership."
Construction of the new Queen Creek Bridge, a cast-in-place multi-steel-span structure, began in April 2024 and should be completed in June 2028.
"The challenging terrain and complex geological conditions have significantly influenced construction activities and added to the overall complexity of the project," Taylor said. "One notable accomplishment has been the careful planning and execution required to remove an entire mountainside within a five-hour work window while still maintaining traffic access before and after operations."
The temporary access road leading to the area beneath the existing bridge, as well as others, "had to be created to all the work areas to allow for safe travel and transport of equipment and materials," Taylor said.
Ames Construction photo
Materials for the bridge construction include ready-mix concrete and fabricated steel beams.
Careful planning for the demolition and reconstruction sequencing is making the bridge work more efficient.
The demolition plan for the existing bridge involves the controlled removal of the concrete deck and girders in sections, followed by the demolition of the remaining bridge components through planned blasting to a prepared working pad below.
The transformation of the Waterfall Canyon Bridge into two box culverts — 5-ft.-6-in. long that stretches across 160 ft. of three-lane roadway — started in October 2024 and should be completed in 2027.
A temporary access road approximately 28-ft. wide was built to permit construction equipment and crews to access the support columns and substructure and store construction materials.
The project uses a range of heavy construction equipment, including a Cat D8 dozer, two Cat 336 excavators equipped with hydraulic hammers, three crawler cranes and two Cat 740 articulated haul trucks. Specialty equipment includes a Bauer BG 45 drilling rig, which is being used for drilled shafts.
The blasting operations targeted some of the steep slopes alongside the highway. Carefully planned and strategically placed charges were drilled and set at heights between 20 and 120 ft. above the road. The force of the blasts brought down large and small pieces of varying types of rock.
After the dust cleared and the landslides ended, excavators (Cat mini-excavators and large John Deere models) began to remove the debris along the road and the temporary accesses built along the slope. The road operations had large loaders, mini-dozers and Cat mini-excavators parked on either side of the blast areas and temporary access roads below the lanes.
"Blasting was required to address safety concerns related to overhanging rock ledges located too close to traffic at two locations along the project corridor," Taylor said. "Removing the large volumes of rock necessary to mitigate these hazards could only be accomplished through controlled blasting. In addition, blasting was essential to create safe and workable access into the canyon, as other potential access routes were not feasible."
Ames Construction photo
The Ames team developed and implemented a comprehensive blasting and blasting safety plan.
"This plan included required pre-activity safety meetings, the installation of physical and temporary barriers and constant communication among guards controlling all access points for both vehicle traffic and pedestrians," Taylor said. "Following each blast, trained personnel conducted thorough visual and physical inspections to verify that the area was safe before allowing re-entry and reopening access."
The temporary access roads above and below the highway were created by blasting, followed by earthwork led by dozers and off-road trucks.
The guardrail replacement and other general maintenance work within and near the Queen Creek Tunnel will be done toward the end of the project.
"Tunnel repairs other than repainting have been completed at ADOT's direction," Taylor said.
Peak days have between 25 and 40 Ames and subcontractor personnel on site. Key subcontractor partners include Keller, GSI, Utah Pacific, TPAC, Endo Steel, Truesdell Corp. and Cactus Asphalt.
Earthwork operations have generated approximately 130,000 cu. yds. of material.
"Some earthwork materials have been able to be used to assist in roadway repair projects after storms in other parts of the ADOT district," Taylor said.
The combination of the rugged terrain and materials removed by blasting, excavation and earthwork activities is taking a toll on the equipment.
"An area of extremely hard rock that could not be blasted for safety reasons due to its location caused some wear to our equipment," said Taylor, who noted that having onsite mechanics helps to ensure rapid repairs and minimize downtimes. The keys to effective maintenance are knowing when to use the right machine for the right task."
Ames Construction is aided in caring for its equipment by Empire CAT and, at times, rents machinery from United Rentals. CEG
