CEC Silverado late last month removed the final 850-ton steel truss of the old East Span Bay Bridge, which crosses San Francisco Bay. Working with Caltrans, crews coordinated the work with the tides to get access when the water was at its lowest. Then, the trusses were cut, pulled out of place and carried away for recycling. In the next phase, set to complete by year-end, demolition crews will remove piers and pilings and extract marine foundations down to the mud line. More than 58,000 tons of steel and 245,000 tons of concrete will have been removed after demolition is complete.
Because it can moderate the damaging effects of earthquakes, base-isolation is a technique used primarily in seismically active regions. ENR takes a look at some of the largest applications of base-isolation technologies in the world.