Using precast and pre-stressed concrete sections designed and manufactured by Con-Fab California, Caltrans and Bridgeway Civil Constructors completed the 21st Avenue Undercrossing Project on Highway 99 in Sacramento in six hours less than the four days initially projected to perform the work. The precast concrete pavement overlays used a polyester concrete mix.

“Our goal was to replace the bridge deck in 99 hours, and thanks to the dedication, hard work, and tenacity of our crews working around the clock, we surpassed expectations,” Caltrans District 3 Director Amarjeet Benipal stated.

The entire Highway 99 repair project, FixSac99, which runs from the north point intersection with Interstate Highways 80 & 50 south to 47th Avenue, is slated to take 99 days, completing by the end of summer.

The recently completed $5.9-million 21st Avenue Bridge Project portion of FixSac99 was entirely funded by Senate Bill 1 (SB 1), the Road Repair and Accountability Act of 2017.

Angela DaPrato, Public Information Officer at Caltrans, stated, “This is probably one of the biggest closures we’ve had in the Sacramento region. This is impacting a lot of people in midtown, downtown, and all different commuters coming in from different directions.”

Caltrans experienced success with the precast, pre-stressed, concrete accelerated bridge construction technique on earlier projects throughout the state. A very similar method was used for the $14.1-million project that replaced the deteriorating Echo Summit Bridge on U.S. Highway 50 in El Dorado County during the summer of 2020.

“This accelerated bridge construction method was very successful in the Echo Summit project. On the Highway 99 project, it’s the first time we’ve really used this magnitude of the accelerated bridge construction method in the Sacramento region,” DaPrato said.

Crews started the work for the bridge deck replacement project offsite by precasting, inspecting, and testing the girders in the construction yard in April. The girders, weighing up to 17.5 tons each, were then hauled to the bridge deck site, where crews bound the girders together and overlayed the deck. The precast components act as both the bridge’s girder system and the bridge deck. The construction team also replaced the sound walls, the concrete median barrier, and installed brighter lighting for the 21st Avenue Undercrossing.

Caltrans District 3 Director Amarjeet Benipal, who is responsible for maintaining and operating 1,500 center-line miles and 4,385 lane miles in 11 counties, said, “Caltrans values innovation, efficiency and partnerships. I want to thank everyone who worked on this project for thinking creatively on how to improve safety and lessen the impact on the neighboring community and the traveling public, while still building a quality structure that will safely serve motorists for decades to come.”

Michael Hein, president of Con-Fab California, was involved in the preconstruction effort. “It’s better to pre-fabricate and pre-make everything offsite and have it all ready to go, so after they demolish the old bridge, we’re ready to bring in this new one. It went seamlessly.”

Here is a brief video showing the underside of the completed concrete bridge work:

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