American River Constructors — a joint venture between Granite Construction and California Engineering Contractors — has prioritized safety and innovation throughout its $131 million rehabilitation of the American River Bridge in Sacramento, California.

One standout safety measure has been the team’s adoption of a “20/20/20” rule. Every 20 minutes, workers stop for 20 seconds to scan the area 20 feet around them. Thanks to this proactive approach, the project has logged more than 100,000 hours worked with only one recordable injury: a broken right ring finger.

The bridge, which carries I-80 Business/Capital City Freeway traffic over the American River, was originally constructed as two parallel bridges in 1954, with a center widening added in 1964. Decades later, it showed significant wear.

“The bridge decks were showing their age,” said Bob Mihal, project executive for Granite Construction. “Due to the severity of the transverse and longitudinal deck cracks, concrete spalling and high corrosive chloride content in the concrete deck surface, the bridge deck needed replacement.”

To facilitate the deck replacement, crews first widened the superstructure to keep traffic flowing during construction. The effort, which began in 2022, is expected to wrap up in spring 2026.

Overcoming environmental and logistical hurdles

Executing the project hasn’t been without challenges.

“There were several significant challenges, including work in an environmentally sensitive floodplain, coordinating with multiple environmental agencies as well as the U.S. Army Corps of Engineers, weathering the series of atmospheric rivers and associated flooding over the winter and spring of 2023, and the technical challenge of rehabilitating a bridge in halves that was originally built in thirds,” Mihal explained.

Access proved particularly tricky. Crews had to work from a barge fleet in the river while maintaining access roads and work pads across multiple winters. Meanwhile, they had to bring materials and workers into the median between live traffic lanes during the first phase of deck reconstruction.

In addition, work in the river was restricted to a narrow window between June and October to protect spawning Chinook salmon and steelhead.

“From November through May, Chinook salmon and steelhead are actively spawning. During those months we were restricted in that we could not actively disturb the river or induce piledriving vibrations,” Mihal said.

Outside of that window, crews worked intensively to install sheet pile cofferdams and bridge piling before the river restrictions resumed.

“Using barges for access in lieu of a conventional temporary trestle bridge was a significant time-saving measure that allowed us to complete the pile driving prior to the river window closing,” Mihal said.

Permitting wins and collaborative contracting

Despite working in a sensitive ecosystem, the team secured environmental permits in just 12 months — far faster than is typical for California infrastructure projects.

“This was a big success for the collaborative construction manager/general contractor process on the project,” Mihal said. “Our environmental permitting experts worked closely with the Caltrans environmental team and collaborated with the various permitting agencies to quickly communicate the project work plans and address any concerns prior to the formal permit applications.”

This early coordination minimized delays and paved the way for construction to begin two years ahead of schedule.

“The collaborative innovations developed during design and construction planning have reduced the project cost by more than $85 million,” Mihal added.

The use of 3D modeling also brought benefits. While Caltrans typically provides 2D design drawings, the project team converted them into 3D models to enhance surveying and field layout.

“This reduced requirements for survey and provided other constructability benefits — everything fits better,” Mihal said.

Engineering decisions that paid off

Working from barges instead of constructing a temporary trestle reduced environmental impacts and avoided potential disasters.

“Any time you build bridge foundations in the river, you impact the river,” Mihal said. “We decided to work off of barges instead of a trestle, which would have basically required building a temporary bridge — and would have had significant environmental impacts.”

That decision proved critical during the atmospheric rivers of 2023.

“A temporary trestle could’ve been swept away,” Mihal said. “Instead, we were able to rapidly move the barges and equipment to higher ground and avoided both equipment loss and environmental damage.”

Looking ahead

As the project nears completion, Mihal sees strong market opportunities despite broader economic uncertainty.

“We see many strong opportunities in the market despite macro-economic uncertainties, and the federal infrastructure bill continues to support growth in construction opportunities,” he said.

Once completed, the new bridge will not only improve vehicular traffic but also offer a multimodal connection between downtown and eastern Sacramento, including a Class 1 bike path linking to the region’s existing cycling routes.

Originally reported by Joe Bousquin in Construction Dive.