East Span Cable Compaction Complete; Crews Begin Installing Suspender Cables
June 2012 UPDATE
The careful effort to compact all 137 strands of the main cable of the new East Span of the Bay Bridge concluded successfully in early June. (See May 16, 2012 update below for details.) With this work completed, the bridge construction team has turned its attention to the next big task: installing the vertical suspender cables that will attach the 5,300-ton main cable to the already-in-place bridge deck, which is currently being supported by a massive scaffolding system.
Crews are uncoiling the all-steel suspender cables (200 in all) from
giant spools, hoisting them up and over special saddle-like fittings
on the main cable, and then pulling them back down to the bridge deck.
The cable ends will then be attached to the bridge deck and, sometime
later this summer or early fall, bridge engineers will begin transferring
the weight of the deck from the temporary scaffolding and onto the
cable system — making the bridge a true suspension span at last.
The new East Span is on track to open to traffic by Labor Day in 2013.
Main Cable Placed on New East Span of Bay Bridge
May 16, 2012
The final strand of the main cable for the signature self-anchored
suspension (SAS) portion of the new Bay Bridge East Span was lifted
into place in early April, marking a major milestone in the construction
of this key seismic safety structure. Workers used a state-of-the-art
hauling system designed specifically for this operation to pull each
of the 137 cable strands from the east end of the span up and over
the tower, then down to loop around the west end, then back over the
tower and down to re-anchor in the east end. 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
completed SAS cable will act like a giant sling, supporting the weight
of the deck.
As the final strand and the Stars and Stripes approached
the crest at 11:10 a.m. on April 5, the crews pounding the strand into
the cable saddle stopped for a few moments to hold a private celebration,
posing with the flag for photographs atop the self-anchored suspension
Once all 137 strands (each made up of 127 high-tensile-strength wires)
were connected to the anchor rods that lock them into place, crews began
the cable compaction process in which four hydraulic compaction devices,
each operating on different sections of the cable, squeezed the strands
together to eliminate any loose space between them. This process was
98 percent complete by mid-May, with only the sections of the cable near
the east end of the span still needing to be compacted. When compaction
is completed in June, workers will have effectively created out of 17,399
wires a mighty, 31-inch-thick steel rope nearly one mile in length and
weighing nearly 5,300 tons. Next up: connecting the main cable to the
deck with individual suspender cables. Work on that part of the project
has already begun, and the new East Span is on track to open to traffic
by Labor Day 2013.
See more on the cable hauling and compaction process here.