Guy F. Atkinson Construction LLC is nearing completion of the California Department of Transportation's (Caltrans) $273 million Interstate 405 Improvement Project in Orange County, Calif., with delivery expected in early fall.
The project covers an 11.2-mi. corridor extending from Interstate 5 to Harbor Boulevard through Irvine, Costa Mesa and unincorporated Orange County. Atkinson began construction in August 2024 after receiving the contract on Aug. 18, 2023.
"The project is improving safety for all modes of travel, increasing the life expectancy of pavement, enhancing traffic operations and mitigating congestion," Nathan Abler, a Caltrans District 12 (Orange County) spokesperson, told Construction Equipment Guide. "It will improve safety for maintenance crews and provide Caltrans with the ability to collect, analyze and utilize data for systems performance along the I-405 corridor."
Planning began in June 2019, and the work is funded through the 2020 State Highway Operation and Protection Program (SHOPP), which is supported by Senate Bill 1, the Road Repair and Accountability Act of 2017. Caltrans developed the project in collaboration with Atkinson, Michael Baker International and HNTB.
Abler said deteriorating pavement conditions prompted the rehabilitation effort.
"Deteriorating pavement was showing surface distress, slab displacement and cracking," he said, adding that the corridor also contained "cracked and settled bridge departure and approach slabs and out-of-date railing."
The project also addresses outdated landscaping and irrigation systems, maintenance access issues and operational deficiencies along the corridor.
Caltrans photo
"We want to minimize the exposure of maintenance crews to live traffic," Abler said, "and address existing unpaved areas, graffiti, minimal maintenance access and outdated irrigation facilities adjacent to the shoulder. There is a lack of traffic system management connectivity and, regarding operational improvements, we are addressing ramp queuing, mainline delay and non-standard access for pedestrians. There is also a lack of a public park-and-ride facility along I-405."
The work includes pavement rehabilitation, bridge widening and rehabilitation, replacement of loop detectors and approach slabs, pavement grinding and grooving, ADA curb ramp reconstruction, bike lane improvements, smart lighting installation, CCTV upgrades, traffic signal modifications and wrong-way warning system upgrades. Traffic management improvements include ramp and roadway widening and modernization of the ramp metering system.
A new park-and-ride facility is being constructed near southbound I-405 at Bristol Street. The facility includes EV charging stations, solar canopies and a battery energy storage system. Crews also are building a sound wall along the southbound I-405 off-ramp to University Drive/Jeffrey Road and six retaining walls.
Most of the current work consists of nighttime curb and ramp construction, paving and electrical activities on both the northbound and southbound sides of I-405. Stage 1 earthwork, drainage and paving operations and all major structural work have been completed. Recent activities have included drainage, electrical, irrigation, landscaping, striping, paving, saw cutting and sealing operations.
"Work has progressed significantly on safety system upgrades job-wide, and the major civil activities for the park and ride," the Atkinson project team said in written responses to Construction Equipment Guide. "The remaining work will focus on the second stage earthwork, drainage and paving operations to complete the ramp and remaining main line improvements. Electrical work is continuing job-wide to wrap up traffic signals and ITS improvements, along with the ADA curb and ramp upgrades."
Atkinson divided construction into two stages. Stage 1 created work areas for half of the ramp improvements and adjacent mainline paving, while Stage 2 shifted traffic onto the completed work and opened areas for the remaining ramp and mainline improvements.
Crews also have worked within tight construction zones adjacent to live traffic.
"A majority of the work requires nighttime lane closures to be completed, so we are working immediately adjacent to traffic," the Atkinson team said. "The day work is staged behind K-rail and access is also tight. … We also deploy a fleet of truck-mounted attenuators to ensure the areas that are not staged behind K-rail are protected."
Crews encountered groundwater at one point.
"We encountered some minor groundwater during our work to extend a triple box culvert in the San Joaquin Channel," the Atkinson team said. "We were able to manage the water with diversion systems and pumping the water and reusing it on site."
Pavement rehabilitation remains a major focus. Existing pavement sections are being removed and replaced with upgraded structural sections, and excavation was required for ramp widening, mainline widening and retaining wall construction.
"Main line cold plane and overlay work is ongoing and needs to be completed prior to the loop installation, which will occur under nightly lane closures," the Atkinson team said. "The plan of attack has been to work simultaneously across the entire alignment to complete the work on time."
Bridge improvements included demolition and replacement of bridge overhangs.
"The bridge work included removing and replacing the existing bridge overhangs to provide additional capacity to carry an upgraded concrete barrier for enhanced safety," the Atkinson team said. "The majority of the concrete is delivered from an off-site batch plant. The rapid set concrete is batched on site using volumetric concrete mixers."
The sound wall was built early in the project to minimize impacts on motorists.
"The [six] retaining walls were constructed in Stage 1 and were scheduled to maintain flow from structure to structure," the Atkinson team said. "The walls are cast-in-place retaining walls, and one ground anchor wall was constructed in front of a bridge abutment. The walls, 170-ft. to 550-ft. long and 5-ft. to 16-ft. tall, were built in sequence, with some overlap."
The 56,000-sq.-ft. asphalt park-and-ride facility has completed paving operations, and crews are finishing electrical, drainage, hardscape and landscape work.
"The park-and-ride took a large portion of excavated material from various locations on the project in order to build the required fill," the Atkinson team said. "The plan was to first get all the excavated material in place for the fills, construct the retaining wall and then continue to the curbs, pavement section and various finishes. Minor excavation was required for the revised final contours, but the majority of the earthwork was fill."
ADA curb ramp work is being completed in phases to maintain pedestrian access.
"One side of the street is under construction while pedestrian traffic is detoured to the opposing side of the street," the Atkinson team said. "The traffic signal improvements are completed in conjunction with the ADA construction as the foundations for the poles are within the limits of the completed ramps. Once the infrastructure improvements are completed, the new bike lanes will be striped and the smart lighting features will be installed."
Earthwork and drainage operations used Cat 322 and 328 excavators, Hitachi 345 excavators, Cat D5 dozers, Cat 950 loaders, Cat CS56 rollers, HAMM 10i rollers, Cat 140M motor graders and a range of support equipment. Concrete paving operations used a Commander III slipform paver, RTP 500 placer and roller screeds, while bridge work has required cranes, under-bridge access equipment and manlifts.
Atkinson said effective communication among field crews, construction management, designers and Caltrans has been critical to maintaining the aggressive schedule.
"The team is constantly problem solving conflicts in the field and implementing solutions in a timely manner," the Atkinson team said. "The communication flows from the field, construction management, through design to the owner and back to the field has been streamlined and has been instrumental in the success of the project."
Peak staffing has reached 250 to 300 Atkinson and subcontractor personnel per day. Major subcontractors include All American Asphalt, California Professional Engineers, Cooper Engineering Roadway Barrier, Drill Tech, Griffith Co., Harber Cos., KDC Inc. and Sierra Landscape.
Material management has focused on reusing excavated material on site. Existing pavement was crushed and reused as base material, and most excavation material was used for embankment fill.
"The majority of the excavated material has been used to fill embankments on site with roughly 15,000 cubic yards required to be exported at the end of the project," the Atkinson team said. "No imported material was needed for embankments on site."
Atkinson imported approximately 60,000 tons of base material.
Because the project operates nearly continuously, equipment maintenance is closely managed.
"For the most part, repairs are completed quickly, within a shift, or the piece is replaced on site if more in-depth repairs are needed," the Atkinson team said. "The key is to have everything in good working order when it is dispatched to the project so it can run hard for a short duration."
