New Bay Bridge nearing significant milestone

May 2, 2012 5:53:19 PM PDT
The new Bay Bridge project is closing in on an important milestone.

Iron workers were busy Wednesday pounding and compacting the single suspension cable that will lift and hold up the new eastern span.

This summer, the temporary support structure will be taken off and all the weight of the span will ride on the cable.

"The cable has got voids in it, or big holes. What compaction does is it presses all of those individual wires down very tightly so you almost have almost a solid piece of metal in there with very few voids. That's what we're looking for. It prevents corrosion and makes the cable stronger," said Caltrans spokesperson Bart Ney.

The cable is made up of 137 strands of wires, 127 wires in each strand. Those 137 strands were looped one by one around the bridge, up and over the tower. Once that was done, the strands had to be compacted from a hexagonal shape to a cylinder.

The workers pound the cable first so the wires settle and align. Then the compactor presses them together at 500 pounds per square inch. Precise measurements have to be met before a steel band is put on and the compactor moves on.

Everything about the project is super sized. Each of the four compactors weighs 30,000 pounds. That's roughly equivalent to six mini vans.

The compacting work should be completed by Monday.

The next big step will come in late summer when the temporary support structure is removed from underneath the bridge roadbed and all that weight is transferred to the single suspension cable, which is nearly a mile long and weighs 10.1 million pounds.

"You can see the end in sight now. We definitely will be making the opening on Labor Day 2013," Ney said.


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