All lanes were open on the San Mateo-Hayward Bridge after 5 a.m. Tuesday following overnight roadwork, a California Highway Patrol spokesman said.
Two lanes were closed from 7 p.m. Monday night to 5 a.m. Tuesday.
The closure allowed work crews to apply anti-corrosive paint to a recently repaired steel beam and complete some other maintenance work, Caltrans spokesman Bob Haus said.
A lane was closed on the bridge from Oct. 12 through Sunday after a crack was found in a steel beam during an inspection.
Repairs involving several steel plates bolted to the beam were completed, and engineers are expected to continue to monitor the beam this week.
No further cracks were found in six other similar beams inspected during the repair work, Haus said.