Caltrans Virtual Community Meeting About PCH Big Rock Retaining Wall Project - Thursday, November 18
Caltrans will hold a virtual community meeting about its PCH Big Rock Retaining Wall Project in Malibu on Thursday, November 18 at 6:00 PM. All community members are invited to attend, learn about the project and ask questions.
- Join the meeting: https://tinyurl.com/w4cmda93.
- Join by meeting number (access code): 2497 653 4262. Password: tVx7ShqrM33.
- Join the meeting by phone: (408) 418-9388
Caltrans is planning a permanent slope restoration on PCH in Malibu. Construction of the $12.4 million project just south (east) of Big Rock Drive is scheduled from September 2022 through July 2023. Utility relocation will take place from September 2021 through October 2022. The work zone spans 180 feet on southbound PCH , which will require shifting lanes toward the hillside to make room for special construction equipment.
Storm damage during the winter of 2015-2016 caused slide damage along this slope, endangering the shoulder and the right southbound lane of PCH. Caltrans assessed the risk to the stability of the roadway and issued a Director’ s Order on June 10, 2016 for an emergency project to apply short-term protective measures to the collapsing slope and shoulder. The project installed a “shotcrete” wall as a temporary fix, but it is now being undermined by sea waves, endangering the southbound shoulder and southbound right lane.
WHAT TO EXPECT
To provide space for construction along the 180-foot stretch of shoulder and roadway, traffic lanes will be shifted toward the hill, with the 10-foot-wide median reduced to 2 feet. There will be three 10-foot-wide lanes and one 11-foot-wide lane during construction, with no shoulder in both directions. The speed limit in the work zone will be reduced to 25 MPH. There will be no pedestrian access in construction area. Bicyclists will be allowed to share right highway lanes. General work hours will be Monday through Friday, 6:00 AM to 9:00 PM. Weekend work is permitted.
The 180-foot beach area is prone to erosion and needs slope protection Permanent slope restoration must be completed as rapidly as possible to prevent erosion, flooding and enlargement of sinkholes that may trigger long-term closures of State Route 1 (Pacific Coast Highway/PCH), an essential route for residents, commuters, emergency services and commercial traffic.
A secant pile wall will permanently restore the slope, 600 linear feet of widened shoulders and 178 linear feet of concrete barrier. The new wall also will dissipate the energy generated by the waves.
Cast in Drilled Holes (CIDH) are high-capacity cast-in-place deep foundation elements constructed using an auger to drill a hole, in which steel reinforcement and concrete are placed. Secant pile walls consist of overlapping CIDH piles, creating a water-tight surface. Two types of piles are used in secant pile wall construction, a “primary” or reinforced pile, and a “secondary” or unreinforced pile. Primary and secondary piles alternate, to create a wall of piles. The main advantages of Secant Pile Walls are: Increased construction alignment flexibility, increased wall stiffness compared to sheet piles, can be installed in difficult ground (cobbles/boulders), less noisy construction.
Jim Medina, Public Information Officer, Caltrans District 7 - firstname.lastname@example.org