Date: September 16, 1997
Media Contacts:
Denine Hagen, (619) 534-2920, [email protected]
San Diego Unified Port District-- Jim Anderson, (619) 686-6224
San Diego Unified Port District Approves UC San Diego Demonstration Of Durable Pier Pilings Made From Recycled Plastic and Glass
Thanks to clean-up and pollution prevention efforts, San Diego Bay is cleaner and attracting more marine life. Among the increasing population are borer worms that dine on the wooden pilings and fenders that support many of the piers along the Bay. As a result, the San Diego Unified Port District must more frequently replace the pilings and fenders-as often as every seven years. Ports across the country are experiencing a similar problem. One solution may be a new design created by UC San Diego Structural Engineering Professor Robert Asaro. His pilings are made from molded hollow tubes of advanced composite materials including glass fiber and vinyl ester resin. Recycled plastic sheaths the tubes and provides an abrasion resistant outer surface. The structural composite materials are strong, lightweight, and immune from seaworm attack. They are also highly corrosion resistant. At its September 16 meeting, the San Diego Unified Port District Board of Port Commissioners agreed to fund a $150,000 demonstration project using the new technology. UC San Diego will design, test, and along with its industrial partners, install and monitor at least 40 16-inch diameter pilings at Berth 24-10 in the National City Marine Terminal.
"The system offers a double environmental benefit," explains Asaro. "First, there is very little pollution created during manufacturing and we are developing a new market for recycled materials. Second, these materials are inert and do not release any toxins into the water. In contrast, wooden pilings have to be treated with chemicals to prevent decay and these chemicals can leach into the water." Adds Rinus Baak, senior director of public works and chief engineer for the Port District: "We are also hopeful that the new piling and fender system will be more durable and cost effective than traditional wooden or concrete alternatives." Although the materials for the composite glass/plastic pilings are more expensive than wood or concrete, the system offers other advantages that may save money in the end. The composite glass/plastic system is light-weight and easier to install. One 40-ft piling can be lifted by a light crane. In contrast, it takes heavy equipment to lift the concrete equivalent. Both wooden and concrete pilings erode and have to be regularly replaced. However, the composite glass is inert, and so has an indefinite lifespan. Pilings and fenders have to be tough and durable enough to take steady beating as ships dock at the piers. The composite glass/plastic system has been carefully strength tested at the Charles Lee Powell Research Laboratories at UC San Diego School of Engineering, and proven to be more resilient than wood and concrete and just as strong as steel. In addition to the San Diego demonstration project, Asaro is currently working with New York City officials to secure funding for a proposed demonstration project to rebuild the 69th Street Pier in Brooklyn. This structure has been shut down because sea worms had eaten away at the pier foundation making it unsafe. Designs and plans for a replacement structure in New York have already been formulated.
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