D
Publish and Present
Claudio Fassardi, MS
Senior Principal Engineer
Jacobs
San Diego, California
The second comprehensive condition assessment of the Middle Breakwater was performed between 2010 and 2014 to provide the U.S. Army Corps of Engineers (USACE) a basis for the planning of future repairs, maintenance and improvements. The assessment indicated that the breakwater did not settle since construction and that the breakwater is vulnerable to the combined effects of waves and high water levels, and earthquakes. For the 12-foot 100-year significant wave height, the 10-ton armor stone appears adequate. In a seismic event, the breakwater’s clay and sand core could be susceptible to liquefaction and deformation. The breakwater appears to provide adequate short wave protection to ships at berths anywhere in the Port, except for service boats at Pier F. With a median annual frequency of failure of 0.0309, which translates to a return period of approximately 32 years, the wave hazard is the dominant hazard.
The median annual frequency of breakwater failure of 0.0309 due to the wave hazard, translates to a return period of approximately 32 years. In August 2014, 31 years after its previous most severe damage in the winter of 1982-83, the Middle Breakwater was damaged again by Hurricane Marie. Scripps Institution of Oceanography Coastal Data Information Program (CDIP) San Pedro Buoy (092) recorded a maximum significant wave height of 11.5 feet, 10 to 15 seconds swell from 165 degrees. The breakwater suffered several breaches, some Port of Long Beach berths were down for couple of days, plus the Navy Mole and Pier J were damaged. The risk analysis proved to be reasonably accurate.