Caltrans and its partners are beginning the first phase of a $133 million project to create a unique protective structure to protect the roadway from rockslides and restore State Route 140 between Mariposa and El Portal, and provide a safe, direct route to enter Yosemite National Park.
“The new structure will offer a unique, sustainable solution to avoid future closures,” said Caltrans Director Malcolm Dougherty. “This is important because SR-140 is a lifeline for local residents and this project will provide a safe and efficient transportation system to enhance Mariposa County’s economy and livability for years to come.”
Motorists are currently constrained by one-way traffic control, using a temporary bypass route. Crews plan to reopen two lanes on the original alignment by clearing the debris and constructing a 750-foot covered structure to protect the highway from future slides.
"SR-140 is one of the key highways that brings visitors from around the world into Yosemite National Park,” said Don Neubacher, Yosemite National Park Superintendent. “We are looking forward to the completion of this important project, which will provide unencumbered entrance to the park."
This project will be built in two phases to help ensure a successful and speedy delivery. During the first phase of the project, Caltrans will remove about 113,000 tons of loose debris caused by the rockslide. This will allow the project team to obtain geotechnical data to determine the best way to build the structure in the second phase of the project to ensure that future rock slides fall on or over the structure and not on the roadway.
This is also the first Construction Manager/General Contractor project to go to construction. This delivery method allows the contractor to collaborate early on in the design phase to find the best solution for the unique challenges that can come up in a repair project.
Construction of the structure is anticipated to begin in 2016.
The project was made possible by the passage of Assembly Bill 1973, which was introduced by Assembly Member Kristen Olsen and signed by Governor Jerry Brown in 2012.
“The citizens of Mariposa County are looking forward to working with Caltrans and their partners as the Ferguson Project on Highway 140 moves forward,” said Mariposa County District 1 Supervisor Rosemarie Smallcombe. “While a construction project of this magnitude will take some time, it should be fascinating!”
SR-140 was damaged in the spring of 2006 during a series of major rockslides at the Ferguson Ridge in Mariposa County. The rock slide covered about 600 feet of the highway. A state of emergency was declared to allow Caltrans to install two temporary bridges to detour motorists around the slide. In 2008, Caltrans modified the existing temporary bridges to allow longer vehicles on the bridges, and began the process to permanently fix the state route.
The structure is currently designed to include two 12-foot-wide lanes, two 8-foot-wide outside shoulders and a 4-foot-wide emergency walkway on the river side. This is the second structure of its kind in the continental United States, and larger than the first rock shed built in 2014 on SR-1 at Pitkin’s Curve south of Big Sur, in Monterey County.