Rebuild Aids to Navigation (AtoN) Structures in Southern California

Project Scope

Contractor: Larison Contracting Corp. (subcontractor to Sustainable Group-Terraphase Engineering JV)

Aids to Navigation (AtoNs) are the lights and daymarks the U.S. Coast Guard maintains on breakwaters, jetties and channel edges. They are the "traffic signals" of the harbor, marking safe channels and hazards so that ships, fishing boats and recreational vessels can navigate safely day and night. Years of wave exposure and salt air had left a number of Southern California's structures corroded or damaged, and the Coast Guard engaged Larison to rebuild fourteen of them along more than 150 miles of coastline, from Channel Islands Harbor to San Diego Bay.

The work included:

• Port of Los Angeles: six Outer Harbor lights rebuilt as new single-pile structures

• Port of Long Beach: a new single-pile structure at Long Beach Light, next to the original

• Channel Islands Harbor: a new steel pedestal structure on the south breakwater

• Mission Bay: three steel pedestal structures on the weir and south jetty

• San Diego Bay: three new spindle structures on Zuniga Jetty

 
Because the sites varied so widely, Larison matched the equipment to each location. At the Port of Los Angeles, the derrick barge DB Ventura extracted the old piles and drove new epoxy-coated steel piles. For the other eight structures, at Channel Islands Harbor, Long Beach Light, Mission Bay and Zuniga Jetty, the old structures were removed and the new ones set by helicopter, placing them on breakwater and jetty foundations that are difficult to reach from land or water. Crews visited each site in advance and built bolt templates and drilling jigs so the new structures, fabricated off site, fit the existing foundations the first time.

All in-water work was completed within the Coast Guard's September–March work window, under marine mammal monitoring and environmental protection requirements, and finished in early 2025.