A program that at first glance might appear as a routine expansion of a desert freeway is actually the culmination of a years-long effort to fully address a host of challenges and considerations, the most important of which is respecting the culture and needs of the Gila River Indian Community, on whose sovereign land most of the project is located. Separate environmental assessments were required to evaluate potential impacts on cultural resources along the full corridor as well as for a new interchange that will support tribal economic development goals.

“Every design decision, every right-of-way action and all proposed construction activity had to be coordinated with the community, state and federal agencies and local authorities,” says Miloš Vasiljević, transportation program management director for HDR, ADOT’s program manager and general engineering consultant for the program. “It just took time to make sure everyone was aligned with what would be built and how it would unfold.”

Another key consideration was minimizing disruptions in a heavily trafficked corridor where options for detours are virtually non-existent.

“There’s no alternative network of roads where you can divert traffic if a section of highway is closed,” Vasiljević adds. “Even a small crash can quickly create miles-long backups.”

In May 2024, Pulice - a Flatiron Dragados company - began the program’s first phase, the $71.2-million replacement of the existing 1,400-ft-long eastbound and westbound Gila River bridges with new three-lane structures that also include full-width shoulders.

As with all other construction teams involved with the Wild Horse Pass Corridor program, Pulice and its subcontractors underwent mandatory cultural training and met other requirements for working on sovereign land, including getting preapproval for laydown areas and major equipment placements. All excavation work was closely monitored to ensure no sensitive resources were affected.

“Otherwise, it was the regular challenges of road construction,” says Pulice senior project manager Reza Kamalizad. “Getting the subs on board, dealing with minor subsurface issues, developing a traffic control plan and making sure we kept motorists and our workers safe.”

With ADOT’s approval, Pulice rephased the project from the original plan, erecting half of the eastbound bridge to accommodate a traffic shift, then building the entire westbound structure. The team then completed the eastbound crossing.

“This approach proved to be much more productive and efficient and allowed better positioning of the crane,” Kamalizad says.

To provide an additional 6 ft of vertical clearance to achieve a more resilient river crossing, each 13-span bridge is founded on approximately ninety 54-in. and 84-in.-dia drilled shafts, the deepest of which reached 118 ft below grade. While some work could take place overnight when traffic volumes were lighter, Pulice elected to place each bridge’s 91 precast UBT 50 girders during daylight hours to ensure the safest operating conditions. Averaging 104 ft in length, the girders were staged before sunrise to ensure everything was ready to get that day’s placement work underway.

With the final girders placed earlier this summer, Pulice is now focused on deck pours and pavement, with an eye toward completing the bridges this fall. For all the project’s initial challenges, Kamalizad says problems over the past two years have been few and far between.

“We have a good relationship with ADOT and the Gila River Community,” he says. “I like to think that this project will set the standard for the rest of the program.”

As with the bridges over the Gila River, two of the program’s other projects are being delivered using design-bid-build. FNF Construction Inc. has begun work on a 10-mile segment from Gas Line Road to just north of Casa Grande, a project estimated to cost $268 million. ADOT has yet to select a team for another three-mile segment between the Gila River and Gas Line Road, projected to cost $158 million. That project is scheduled to get underway later this year, the agency says.

For the corridor’s more complex 11-mile northernmost section, ADOT elected to use design-build, tapping a team led by Coffman Specialties Inc. and Fisher Sand & Gravel Co. for the $410-million assignment earlier this year.

Because the section of I-10 serves several towns as well as the Gila River Community’s casino and entertainment district, Vasiljević says it was essential to explore alternative technical concepts that could integrate the infrastructure improvements with the least amount of disruption to residents and visitors. The section includes four existing interchanges that will be expanded or rebuilt, with one augmented with a new flyover structure. The Coffman-Fisher team will also construct a new diverging diamond interchange and expand an existing crossover bridge.

“Design-build allows us to incorporate the optimal means and methods for each situation,” says Armando Garcia, construction manager for Coffman Specialties, adding that planning maintenance of traffic will be as important as phasing the structural work. “We’ll also have more flexibility for configuring our machines and operations to provide a better project.”

Another concept proposed by Coffman-Fisher is the use of concrete pavement instead of the originally specified asphalt.

“Being a heavy truck corridor, long-term maintenance will always be a consideration,” Garcia says. “We expect the concrete to last at least 30 years, and without the problems that can result from prolonged exposure to extreme temperatures.”

Vasiljević says these approaches make clear how seemingly straightforward projects offer opportunities for innovation.

“It was just amazing to see the process work the way you hope it would, with all the stakeholders coming together through the process and coming up with ideas that will result in a better project,” he says.