The Columbus Drive bridge over the Chicago River closes Friday for almost a month of weekday repairs.

Starting Friday, the bridge closes to all traffic from 9 a.m. to 4 p.m., Monday through Friday, until April 21, the Chicago Department of Transportation said.

Construction will continue after that, but for only half of the bridge at a time, CDOT said. Vehicles will be limited to two lanes and pedestrians to one sidewalk.

CDOT did not say how long the second phase of repairs would take.

Columbus Drive traffic will be detoured to Lake Shore Drive until April 21, the department said.