The work includes replacing handrails with more crash-resistant steel barriers to protect the bridge from vehicle crashes.
Pedestrian access on the bridge will be limited because the work requires the removal of the sidewalks on each side.
Although one sidewalk will remain open at all times, there will be pedestrian detours during the project.
There may be single-lane closures from 9 a.m.-4 p.m. and full bridge and directional closures from 6 p.m.-6 a.m., except on Wednesday and Sunday nights, when they will start at 9 p.m.
The bridge will be closed from 9 p.m. Friday-6 a.m. Sunday for about 25 weekends. Superior Construction Co. of Jacksonville is the contractor.
Drivers and pedestrians who use the Main Street bridge will have to make adjustments for the next year while the Florida Department of Transportation completes an $11.1 million project.