The Bay Bridge reopened this morning, after six long days, but it could close down for a more permanent fix to a cracked eyebar in another few months.

Caltrans officials said this afternoon that the repairs they worked on meticulously for the past six days made the Bay Area's busiest toll bridge safe. But they're investigating a number of other long-term solutions that would require less monitoring and maintenance.

"It is a temporary fix," said Richard Land, Caltrans' chief engineer. "But a long-term solution might be needed. Right now the plan is not to keep the current (repair) in place long term."

Caltrans engineers are analyzing a number of long-term repairs that people inside and outside the agency have suggested, Land said, including replacement of the cracked eyebar - a major undertaking. Instead of designing the repairs under time pressure, with the bridge closed and commuters fuming , Caltrans would plan the work and schedule a closure, perhaps in four to five months, he said. The length of the closure would depend on the type of repair chosen.

The work that crews performed since Tuesday, when a repair to fix to a cracked structural beam came crashing down on the upper deck, allowed Caltrans to reopen the bridge just after 9 a.m. today.Tests conducted overnight and this morning on an altered version of that repair job showed that the fix was holding, Caltrans spokesman Bart Ney said.

At 9:01 a.m., a fleet of five California Highway Patrol cars escorted the first private vehicles allowed onto the westbound upper deck since the span was shut down Tuesday evening.

About 10 minutes later, the lower deck reopened for traffic heading to the East Bay.

"We're happy to be returning the Bay Bridge to public service," Ney said.

However, hundreds of commuters heeded Caltrans' warning Sunday that the Bay Bridge would not be open for the morning commute, jamming other Bay Area bridges and crowding on to BART. BART reported that transbay ridership was up 85 percent this morning. The agency said that even though the bridge was open, it would run longer trains for the evening commute to accommodate the extra surge in riders.

Overnight, crews were able to "get the geometry" in place with respect to key parts on the bridge and conduct stress tests on the cracked beam, Ney said.

"What changed is we got the steel into alignment, so we were able to go forward with the stressing," Ney said.

"Safety is our priority," he said. "Clearly, we have taken our time with implementing this."

On Tuesday evening, high winds and heavy traffic created vibrations that loosened a pair of tie rods and a steel bracket installed over the Labor Day weekend to take pressure off a fracture discovered in a structural beam - an eyebar - on the eastern span.

The 5,000-pound assembly crashed onto the upper deck, damaging three cars but causing no serious injuries.

After fixing the tie-rods and bracket assembly last week, work crews performed a stress test Saturday evening on the repairs to see if the metal parts continued to scrape against each other and weaken the overall assembly.

Halfway through the three-hour test, workers declared the repairs a failure because the tie rods were continuing to scrape together. After taking a seven-hour break starting about midnight Saturday, work crews spent Sunday realigning the assembly and grinding and smoothing the metal parts.

During stress test late Sunday, workers used a mechanism to pull at the entire assembly, which allows them to measure the amount of strain it can withstand.

Ney said Caltrans would be conducting daily inspections of the repaired area of the span, just east of the S-curve, to ensure it is holding.