CONTENTIOUS BAY SPAN APPROVED

Despite protests by seven Bay Area mayors, an Oakland-based regional commission June 24, 1998, approved controversial design plans for replacement of the seismically rickety half of the San Francisco-Oakland Bay Bridge. Contractors are now angling for piece of the estimated $1.5-billion project, which involves replacement of 2.2-mi (3.5-km) stretch of Interstate 80 where 50-ft (15-m) section of the upper bridge deck dropped during an earthquake in 1989. Among the technical challenges contractors must ponder is how to hammer 8-ft-dia (2.4-m) tubular steel piles 300 ft (91 m) through mud and clay into dense sand. In mid-bay near Yerba Buena Island, the route will rise up to what would be the world's largest self-anchored single-tower suspension bridge. Anchored in the 0.35-mi (0.56-km) twin bridge decks, the cables will drape from 530-ft-high (162-m) tower founded on abruptly sloping rock. Critics say the engineers short-changed the viaduct design; others like what one adviser describes as a simple and elegant line of white.