The Bridge...

Federal officials have given their approval for a temporary fix for the troubled new eastern span of the Bay Bridge, reviving the possibility that the span could open just after Labor Day, officials said.
The Federal Highway Administration said the short-term fix for snapped high-strength steel rods that hold seismic-stability structures together would provide a "comparable level of seismic performance."
"As such, we see no reason to delay opening the bridge to traffic," Vincent Mammano, a division administrator with the federal agency, wrote in a letter Friday to Steve Heminger, executive director of the Bay Area Toll Authority.

The letter comes a month after transportation officials called off the planned Sept. 3 opening for the new bridge and said it may not be ready until at least December. But days later, an independent review panel suggested an interim fix that federal officials are now supporting.

Bridge officials discovered in March that 32 of the 96 bolts used to attach a pair of seismic devices known as shear keys to the bridge had broken when tightened.

Shear keys are one of two types of seismic safety devices on the eastern span. The other device, bearings, allow the bridge decks to move slightly. Shear keys prevent them from moving too much.
The temporary fix calls for installing steel plates - shims - in gaps between bearings to prevent them from swiveling. That would effectively limit horizontal bridge movement in a major earthquake, and allow the span to open well before December.

Crews would continue to install a permanent fix - steel saddles, devices used to strap the shear keys to the bridge piers. The shims would be removed once that work is completed.

A federal review team "was impressed with the level of expertise used to fashion this interim means of limiting the movement of the bearings so they engage and safely transfer seismic forces," Mammano wrote.

The new eastern span was commissioned after a portion of the existing bridge failed in the 1989 Loma Prieta earthquake. Several experts have said the new span - even with its bolt issues - is likely to be safer in an earthquake than the one drivers are using now.

State Sen. Mark DeSaulnier, D-Walnut Creek, head of the Senate Transportation Committee, said Tuesday that the federal letter was "encouraging."

"It's in everyone's best interest to get people off the old bridge and on the new one as soon as we determine that it's safe," DeSaulnier said.