BIG SUR >> Caltrans will conduct a full overnight closure on Thursday to switch traffic over to the completed section of Highway 1 at the Rocky Creek repair site where a slip out, nearly a year ago, took out a section of roadway.

“The traffic switch to the southbound lane is truly a milestone moment in this repair as it signals completion of the southbound viaduct structure,” said Caltrans District 5 spokesman Kevin Drabinski.

On March 6, flaggers will begin intermittent traffic control at 8 p.m. with delays of up to 10 minutes before the full closure goes into effect, beginning at 10 p.m. Caltrans will conduct the overnight closure which will prohibit travel through the site situated 12 miles south of Carmel. Caltrans says that by 6 a.m. on March 7, one-way traffic control will resume allowing the flow to and from the Big Sur area which will now traverse the southbound viaduct-supported roadway.

“We have received positive feedback from business owners on the coast who say the temporary signals at this location have not been a detriment for their workers’ commute and there is an increasing understanding by the general public that the Big Sur coast remains open for business,” said Drabinski.

The schedule for the traffic switch and full overnight closure is weather dependent. Updates will be provided to confirm or announce any changes to this schedule.

“Less than one year ago, on March 30, 2024, there was no southbound lane at all due to the slip out at this location,” said Drabinski. “The southbound lane is now supported on solid ground and work can begin on the northbound viaduct structure.”

Caltrans continues emergency repairs to Highway 1 near the Rocky Creek Bridge — post mile 60 — where the slip out resulted in a loss of a section of the southbound lane disrupting the flow of traffic to Big Sur for a time before measures where taken to restore vehicle passage using only the northbound lane. Caltrans established one-way, 24-7, signalized traffic control to allow for travelers to access activities and businesses in Big Sur.

The emergency repairs to Highway 1 included the construction of a viaduct to support the roadway and repairs to a concrete seawall at the base of the cliff.

Crews drilled and cast reinforced concrete columns to support the weight of the viaduct structure in advance of the installation of girders. The design of the viaduct involves support from the two ends as well as two support columns in the middle which make for a three-span design.

Three girders were placed across three spans totaling nine concrete girders, ranging from 45 to 65 feet in length, that were installed in mid-December.

“Even though wind and rain delayed by a day the installation of the nine precast concrete girders in December, the relatively mild winter has been worked to the advantage of our crews,” said Drabinski.

Prior to the girder installation, other construction-related tasks over the past several months included crews drilling holes, lowering rebar cages inside and pouring concrete to create the support columns. The concrete girders serve as the support structure for the southbound lane of the viaduct bridge deck.

“Like many repairs on the Big Sur coast, tight quarters are a challenge to this project,” said Drabinski. “At this location this has been complicated by the fact that there was a sheer drop off to the ocean below during work on the southbound structure.”Caltrans estimates the completion of the Rocky Creek viaduct system to be summer 2025 and is dependent on conditions encountered during construction.

“We are able to lean in to the seasoning and experience of engineers from every kind of background who understand the unique nature of projects on the coast,” he said.

The contractor for this project is Gordon N. Ball, Inc. of Walnut Creek. The estimated price tag for the repair work at the Rocky Creek slip-out is $21 million.

Though Highway 1 to Big Sur is open allowing travelers from Northern California to visit the Big Sur coast. The coastal highway remains closed 40 miles south of Carmel due to the Regent’s Slide — post mile 27.8 — which occurred March 9, 2024, and where top-down removal of slide material by crews began on April 30.

Travelers to the Big Sur coast from southern California will also encounter the closure of the coast highway at Regent’s Slide. The vast majority of the Big Sur coast remains accessible and open.

In August, while excavating the slope at Regent’s with bulldozers, crews noticed surface cracking at several points around the area being excavated, indicating additional Regent’s Slide activity.

“We continue to see slide movement at Regent’s as a result of recent rains,” said Drabinski. “On average, the slide which appeared in August moves at one foot per day. We continue to excavate when conditions permit and back off when the slide below is active.”

Drabinski added that there is still no estimate on reopening at Regent’s Slide.

Nearly a year ago, Regent’s Slide originated 450 feet above the roadway displacing material that engulfed Highway 1 and continuing down to the beach and ocean below. While Caltrans has made progress toward reopening the roadway, repair efforts have been challenged by the height and steepness of the slope, which have required flexibility and frequent adjustments to repair strategies to ensure the safety of workers on site. Continued slide activity has extended its reopen date.

Road information and updates can also be found on Caltrans District 5 Social Media platforms: X/Twitter at: @CaltransD5, Facebook at: Caltrans Central Coast (District 5) and Instagram at: Caltrans_D5.