The intersection of High Street and South Limestone was closed to traffic for about three weeks, beginning at 9 a.m. Thursday.
The closure allows work crews to replace storm and sanitary sewers and to do underground utilities work, according to city officials.
While motorists cannot drive through the intersection, two-way traffic will be allowed on portions of the usually one-way High Street.
Two-way traffic will be allowed on High between Martin Luther King Boulevard and Limestone Street, and between Limestone and Upper streets.
The work is part of a major overhaul of South Limestone Street between the Avenue of Champions and Vine Street that is expected to take about a year to complete. That stretch of South Limestone is closed to through traffic.