PHOENIX – Several major bridge and intersection replacement projects in southern Arizona presented a big challenge for the Arizona Department of Transportation in 2020: How to replace existing structures or entire interchanges without closing highways on projects that last up to two years.
The agency applied several innovative approaches to do just that, keeping passenger vehicles and commerce moving while minimizing potentially disruptive restrictions and closures.
Drivers are benefiting from the strategies at several key projects: The Interstate 10/Houghton Road interchange in Tucson, the Pinto Creek Bridge replacement on US 60 near Globe, a bridge replacement project on SR 77 in Winkelman, and the I-10/Ruthrauff Road interchange replacement project in Tucson.
The I-10/Houghton Road interchange project in Tucson began in August, a project that involves replacing a two-lane Houghton Road bridge with a six-lane diverging diamond interchange, along with rebuilding all ramps. While replacing an interchange sometimes requires extensive closures, ADOT will complete this project with only a three-month closure of two ramps - both of which have already reopened. The other two ramps and bridge are being constructed next to the existing lanes of traffic, and traffic will eventually shift to the new pavement. For the remainder of the project, only overnight closures are anticipated as traffic flows through the busy work zone.
On US 60 between Globe and Superior, ADOT has been working since late 2019 to replace the 70-year old Pinto Creek bridge in an area with rugged terrain and hour-long detours around any highway closures. However, the project required months of blasting that could only occur when US 60 was closed. ADOT’s solution was to limit closures to four hours at the same time and on the same three days of the week, ensuring motorists had a predictable schedule to plan their travels. Since the blasting wrapped up earlier this year, the highway has remained open while the project team works on the new bridge next to the existing structure. A five-day closure is anticipated toward the end of the project in 2021 as crews realign the road to the new bridge.
In Winkelman, ADOT is working to replace the two-lane SR 77 bridge over the Gila River without closing it or shifting the highway. Crews are able to do this by essentially cutting the bridge in half and rebuilding one side of the structure at a time. Since the project began in late 2019, traffic has continued to use the bridge, restricted to one direction at a time as a temporary signal regulates which direction can proceed. Delays are generally less than 15 minutes, with occasionally longer delays for two weeks at a time when new bridge girders have been set into place. The new bridge will open by summer 2021 without any extended closures of SR 77.
At I-10 and Ruthrauff Road, one of the most heavily traveled segments of the Interstate in Tucson, ADOT has been working since January to replace a 60-year-old interchange without closing the highway. ADOT has maintained three lanes of travel in each direction during peak hours with several traffic shifts onto either the frontage road or newly rebuilt lanes of I-10. While the interchange has been closed most of 2020 and the project won’t be complete until late 2021, ADOT has made it a priority to reopen Ruthrauff/El Camino del Cerro across I-10 by summer 2021 to minimize the impact of the project even as other elements of the project will remain under construction. Also, ADOT’s contract with Sundt Construction encourages an aggressive construction schedule with an early completion incentive for finishing the project 40 days sooner than the contractor’s specified completion date. The goal is to only have the interchange closed for the 2020 holiday travel season and open again before the holidays in 2021.