The San Francisco Bay Bridge opened its gates eleven hours earlier than scheduled. The bridge was closed down for major renovations as part of a seismic retrofitting project.

Commuters had a nice surprise that the bridge was open for traffic eleven hours earlier than the 70 hours predicted initially.

“I’m just glad the bridge opened on time,” San Francisco resident Edward Solomon said. “I can’t imagine what everyone would have done without that bridge during a weekday.”

During the 70 hours of work, crews demolished a piece of the upper deck east of Yerba Buena Island, and early Monday morning, they installed the new 6,500-ton, 350-foot portion of Interstate 80.

More than 2,700 tons of concrete and steel made up the replacement piece that was moved into place, according to Rancho Cordova-based contractor C.C. Myers. Caltrans scheduled five hours for the fitting, but it took less than three hours. After the piece was in place, crews Monday assessed the lower deck of the bridge, which sustained minor damage from falling chunks of steel and concrete during the weekend demolition.

“Even though some of the demolition was very stubborn, they managed to make up time because it was such a perfect fit,” Caltrans spokeswoman Margena Wade said.

Caltrans closed the bridge at 8:07 p.m. Friday and had scheduled its reopening for 5 a.m. today. It was the first total closure for the Bay Bridge since the devastating Loma Prieta earthquake in 1989 damaged the upper deck. The next bridge closure is expected in 18 months.