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.

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 span's tower.

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.