Granite Construction Co. is well on its way to delivering the Arizona Department of Transportation's (ADOT) $171 million Interstate 10 Reconstruction between Ruthrauff and Ina roads project by December 2025.
The project is designed to improve safety and traffic flow between the two interchanges around northwestern Tucson.
Construction began in February 2023.
The project was combined with Pima County's $34.95 million project to extend Sunset Road between I-10 and River Road, which was being constructed simultaneously.
Arizona Department of Transportation photo
The combined project includes 4 mi. of I-10 and 0.7 mi. of Sunset Road. It is financed by state, Federal Highway Administration (FHWA) and Pima County funds.
"This project will increase roadway capacity and improve operational efficiency of this portion of I-10," said Garin Groff, an ADOT public information officer. "ADOT works with other jurisdictions frequently, including on local public agency projects."
When completed, there will be five travel lanes in each direction — an increase of two — with auxiliary lanes between on-ramps and off-ramps.
Granite is reconstructing the existing traffic interchanges at Orange Grove Road and Sunset Road, which will be improved by constructing a new roadway over I-10 and the railroad at Sunset Road.
The I-10 main line profile will be raised at Canada del Oro Wash and Rillito Creek to provide sufficient floodway clearance.
Granite also is constructing new bridges to carry Sunset Road traffic over the Union Pacific Railroad (UPRR) and the Rillito River; replacing all nine bridges in the project area, including those over Canada del Oro Wash and Rillito River; constructing retaining walls throughout the project area; installing drainage and lighting; adding landscaping and other improvements; and placing an access path to the Chuck Huckelberry Loop from Sunset Road.
Pima County's project is based on improving mobility in the vicinity of the I-10 Sunset Road interchange by connecting Sunset Road from I-10 to River Road.
The sections under construction experience heavy traffic, with some carrying 45,000 to 53,000 vehicles daily. The improvements will boost that to 88,000 to 101,000 vehicles.
The project's first phase, which started in early 2023, shifted traffic to roughly 3 mi. of existing frontage road, providing three lanes of travel in each direction.
Arizona Department of Transportation photo
A second phase from April 2023 to March 2024 dealt with the reconstruction and widening of the main lines, the start of new bridges for I-10 and reconstruction of the Orange Grove Road interchange.
The third phase, which lasted from June 2024 to February 2025, dealt with the Orange Grove Tie-in, work on the Sunset Road interchange and construction on the Sunset Road extension to the east of I-10.
The project's fourth phase, the Sunset Interchange/Sunset Links, began in February.
This work consists of building a new access to the interstate by extending Sunset Road east of I-10 to River Road. This involves building new bridges over the Union Pacific railroad tracks and the Rillito River. This extension will then connect to River Road, creating a new link to I-10 from the east.
The Sunset Road interchange is expected to open in conjunction with the project's completion in late 2025.
Granite has encountered and overcome several hurdles.
"One of the biggest challenges we faced early in the project was executing the traffic switches — particularly the transition from Phase 1 to Phase 2," said Paul Preston, Granite's area manager. "According to the plans, we needed to shift 24 lane-miles of I-10 traffic onto a newly constructed frontage road detour, all within an eight-hour overnight window. This involved obliterating old striping, restriping, placing raised pavement markers and installing new signage across 13 lane-miles — while keeping I-10 open to traffic the entire time. To manage this, our team came together and developed a phased approach."
Bridgework also proved challenging.
Arizona Department of Transportation photo
The I-10 bridges with precast prestressed girders and concrete decks consist of the CDO Wash Bridge — 355 ft. long and three spans; the Orange Grove Bridge — 132 ft. long and one span; the Rillito River Bridge — 255 ft. long and three spans; and the Sunset Road Bridge — 218 ft. long and two spans.
The Sunset Bridges, based on a similar design, consist of the Union Pacific Railroad Bridge — 209 ft. long and one span along with steel girders, and the Rillito River Bridge — 377 ft. long and three spans.
"All the bridges in this project are being constructed using a consistent substructure approach, with some variations based on site-specific needs," Preston said. "After demolishing the existing bridges, we prepared level drill pads for our drilled shaft foundation subcontractor. Each bridge is supported by drilled shaft foundations, with shaft diameters of 48 in., 60 in. or 70 in. and depths ranging from 74 to 104 ft. In total, we installed 121 shafts.
"Once the shafts were completed and approved, Granite constructed cast-in-place concrete columns — each 48 in. in diameter, with varying heights depending on the bridge. After the columns cured and reached design strength, we began forming the piers and abutments.
"To address flood risk, we used an EFCO form system for the piers, which bolts directly to the columns and is elevated above the riverbed. Once the piers and abutments were stripped and backfilled, the substructure was complete."
The superstructure varies slightly between bridges that use precast concrete girders and those using steel girders.
"Our girder subcontractor mobilized cranes to set the girders," Preston said. "For the precast concrete girder bridges, Granite forms the bridge deck using removable wood forms. For the steel girder bridges, our subcontractor installs permanent steel decking. Once the deck is formed and rebar is tied, we pour the deck using three concrete pumps. The surface is finished with a Bid-Well Concrete Paver and cured and textured using a cure bridge. After the deck reaches full strength, we install the approach slabs and armor joints. The final step is installing the barrier rail."
Bridge construction crews used a Bid-Well concrete paver and work bridge, a Grove 90-ton crane, a Liebherr LTM1400-7.1 crane, a Manitowoc MLC300 VPC-MAX lattice-boom crawler crane, manlifts and reachforks.
Bridge demolition was handled by Granite's DBE subcontractor, Ground Level.
Arizona Department of Transportation photo
"They used a combination of heavy equipment — including excavators equipped with shears and hammers, as well as a ball-and-chain setup — to safely bring down the existing structures," Preston said. "Once the bridges were on the ground, the materials were rubblized for removal and recycling. minimizing disruption to surrounding areas."
Regarding drainage and underground infrastructure, crews are replacing and installing extended culverts and storm drains to facilitate the widening, accommodate new structure locations and support added weight.
"Facilities were constructed to collect surface draining on the north and southern sides of Ruthrauff Road. Flows on the southern side conveyed to the northern side at Highway Drive and the railroad abutment," said Groff, "and then conveyed west toward the Santa Cruz River. They are constructing a closed roadway pavement drainage system."
The I-10 roadway is mostly concrete surfaced except for the inside shoulders, which are asphalt. Sunset Road is asphalt. CEG
