The first prefabricated bridge built in Arizona was installed in Mohave County on Oatman Highway along Route 66 over the Sacramento Wash in Topock March 13-16. The Arizona Department of Transportation (ADOT), in partnership with Mohave County and the Federal Highway Administration (FHWA), hosted a Prefabricated Bridge Elements Showcase in Laughlin during the install effort.

Agency Representatives, engineers, and contractors from all over the country came to observe the bridge project and to hear presentations on how the entire project came together.

“This is not only the State’s first prefabricated bridge, but it’s also one of only 54 accelerated bridge construction projects in the state,” said Supervisor Buster Johnson. “By combining these two methods together we were able to save an estimated $2.6 million in lost road-user impact fees which include business hardships, additional time added to a driver’s commute, and loss of revenue for the county.”

Supervisor Johnson has been working on a solution for the Sacramento Wash flooding since taking office twenty years ago. While the second part of the project will still need to be completed in order to elevate flooding in the area, completion of the bridge is still the first step in a long awaited solution.

“I would like to thank all the agencies and the Contractors for the diligent work they did ensuring this part of the project was successful,” Johnson said.

The 110-foot bridge was manufactured in Phoenix and then transported in sections to the site. The offsite work consisted of constructing a new bridge, roadway approaches and channel improvements to be installed within Mohave County’s 100 foot right-of-way.

The right-of-way was turned over to the County by the State in 1988 and is currently the only County owned section of the Sacramento Wash.

“All of the installation and work had to be done within this right of way. The land adjacent to the project is owned by the federal government and allowing cranes or any equipment on the land would have required an environmental clearance that was not possible to get within the limited 6 month construction bid timeline,” Public Works Director Steve Latoski said.

The project was partially paid with a $1 million federal grant that required it to be completed within 6 months of funding authorization.

The accelerated bridge construction concept brought the installation of the bridge down from the original closure time of 5 weeks to 96 hours. The only other way to get to the Golden Shores/Topock area is by taking a 24 mile detour around Needles, California.

“Having to close County Route 1 at Oatman Highway for five weeks would have put a hardship on residents of Golden Shores and Topock along with visitors and commercial traffic to the area,” Johnson said. “By shortening the duration of the closure, we were able to save $1.1 million in estimated closure fees.”

Accelerated bridge projects are becoming more common around the country. According to the FHWA, these projects have saved 40% in engineering costs and 75% in resource demand versus traditional bridge construction methods.

The Sacramento Wash at this location spans 1330 square feet and empties into the Colorado River. The bridge was built to withstand a two-year, 30-minute storm event. Latoski said that any precipitation that falls in the wash ultimately discharges into the Colorado River where it crosses Oatman Highway.

A second project is underway by the County to obtain a Special Use Permit from the US Fish and Wildlife Services to remove a man-made dike and divert the Sacramento Wash to its historic flow which will then evaluate major flooding in the area. Mohave County averages 21 swift water rescues a year in the area.