Upgrading the San Francisco Bay Bridge with SeaTimber proved more than a green move.

It saved the bridge from heavy damage in a spectacular collision.

Dense fog shrouded the famous San Francisco Bay Bridge on the morning of 7 November 2007, when the Cosco Busan, a 250-metre long container ship, slammed into the base of one of the bridge’s support towers.

The accident caused a major oil spill and tore a gash in the vessel’s hull, but the Bay Bridge itself – linking the business and transportation hubs of San Francisco and Oakland in California’s Bay Area – took the collision in its stride, thanks in part to a Trelleborg innovation giving recycled materials a renewed lease on life.

The protective fenders girding the piers rising from the bay had recently been replaced with an innovative, durable and shock-absorbent synthetic lumber made by Trelleborg.

SeaTimber is produced from 100% recycled high-density polyethylene which, in its previous life, may well have been a milk container that ended up in a recycling bin.

“The plastic upgrade proved invaluable to the environment,” says Mick Langford, sales manager for Trelleborg Marine Systems USA, a unit within Trelleborg Engineered Systems. “Had the Bay Bridge fenders still been original wood, they would have been in an advanced state of deterioration and would have offered almost no real protection,” he explains. “Plastic may have prevented the worst, which could have been a catastrophic collapse of the bridge.”

SeaTimber and its vertical cousin, SeaPile, are the products of choice when it comes to renovating and shoring up bridge piers, ports and marinas around the world.

One reason for this is that the synthetic logs can be manufactured in different measures of flexibility as well as different lengths and colours. Unlike wood, they are not susceptible to rotting in the water or falling prey to marine borers. That is good for the environment, as they do not have to be treated with creosote and other toxic materials that leach into the water over time.

SeaTimber has a lifespan of 40 to 50 years compared with five to 10 years for wood. “Not only is it a green alternative, it’s also much more flexible and therefore able to absorb and deflect energy,” says Langford.

“The very first major installation was at the port of New Orleans. Over time, more and more people started using it, once they looked at the life-cycle cost benefits.”

Minett Media

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