Caltrans reports that workers last week placed the “world’s largest cable saddle” atop the new San Francisco-Oakland Bay Bridge’s self-anchored suspension span (SAS).
The tower for the SAS, the signature element of the bridge’s new span, will stand tall at 525 feet.
The cable saddle weighs approximately 450 tons, and while it has a rectangular flat base, two sides jut out, according to Caltrans bridge spokesman Bart Ney.
“The top is curved to better carry the cable over the top not just once but twice, making it one of the few double cable saddles in bridge construction and the largest and heaviest for a suspension bridge,” says Ney.
The base is 23.8 feet long and 19.7 feet wide. The saddle’s length stretches to 32.8 feet close to the top. At the saddle’s curved apex, it is 13.7 feet tall.
Ney says strand jacks hoisted the cable saddle more than 500 feet into the air and placed it onto a single steel component that was put atop the four tower legs on April 15. This section will evenly distribute the weight of the cable saddle, and eventually the cable, among the four tower legs.
The steel saddle will carry the SAS’s nearly 1-mile-long single cable. Ney says that unlike traditional suspension bridges where the cables are anchored into the ground, a self-anchored suspension bridge’s cable is anchored in the road-decks. The cable will anchor into the east end of the roadway, travel up and over the tower to wrap around the west end before traveling back up and over the tower to anchor back into the east end; in other words, the 2.6-foot-wide cable will act like a giant, unbelievably strong sling, he says.