San Francisco-Oakland Bay Bridge:-
The newly built $6.4-billion eastern span of the San Francisco-Oakland Bay Bridge reopened on Monday evening, Sept. 2, 2013 nearly a quarter-century after a deadly earthquake during the 1989 World Series collapsed two 50-foot sections of the old structure.Part old and part new, part permanent and part temporary, the hybridized bridge opened late Monday night in time for Tuesday’s morning commute. The 6.9-magnitude Loma Prieta quake hit just as millions tuned in to watch Game 3 of the "Bay Bridge World Series" between the Oakland Athletics and San Francisco Giants, killing 63 people and causing up to $10 billion in damage.
On September 2, 2013, the new East Span of the San Francisco-Oakland Bay Bridge opened to traffic. The seismic opening of the new span is more than just an upgrade of one of the country's busiest bridges--it is an epic transformation of the bridge into a global icon.
For the first time in history, pedestrians and cyclists have the chance to travel on the San Francisco - Oakland Bay Bridge. The 15.5-foot-wide bike and pedestrian path opened to the public at 12 p.m. on
September 3.
The Guinness World Records has crowned the new East Span the widest bridge, with a total deck width of 258.33 feet (78.740 m), including 10 lanes of roadway, a 15.5-ft-wide (4.724-m) bike path and a gap where the central tower supports the two bridge deck sections.
In a traditional suspension bridge like San Francisco's iconic Golden Gate, engineers use inches-wide steel cables to hang thousands of tons of concrete and steel over water, and those big cables anchor to the shore. The new eastern span of Bay Bridge, designed by the joint venture of T.Y. Lin International and Moffatt & Nichol, can't rely on the too-small nearby rock or the surrounding muddy ground—which amplifies seismic movement—for support. So the bridge goes it alone, anchoring its 35,200-ton side-by-side steel decks to itself.
The bridge will use a single 2.6-foot-diameter main cable looped around the roadway and held high by a single 525-foot tower. The 10.6-million-pound cable is composed of 137 wire bundles, each consisting of 127 5.4-millimeter-wide steel wires.The cable acts like a giant rubber band.It supports 90 percent of the bridge's weight. From the main cable, 200 steel wire suspender ropes grab hold of the 28 steel roadway decks.
To stay strong during earthquakes, the tower splits into four steel legs, and the ones that are farther east on the bridge were driven at an angle through more than 300 feet through mud to rest on bedrock. The tower legs are joined by plates called shear links, which stiffen when the wind gusts to keep the bridge stable. In an earthquake, the shear links absorb the earth's movement. They're designed to break if the quake is strong enough, to prevent damage to the rest of the bridge
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