A key and historic bridge over the Calumet River on the Far South Side will be closed for more than a year beginning Monday for reconstruction.

Work on the vertical-lift Torrence Avenue bridge, which lies just north of 126th Street, will close Torrence to through traffic from 122nd to 126th streets.

Built in 1938, the Torrence bridge is the only city-owned vertical-lift bridge, so named because the bridge's center section lifts straight up to allow ships to pass underneath. The bridge raises and lowers more than 100 times a month, city transportation officials said.

There actually are two separate bridge structures--one roadway, one railroad. It is the roadway bridge that is being rebuilt. The bridge will be rehabbed in the up position, about 120 feet in the air.

The $24.1 million project is expected to continue through fall of next year.

Car traffic will be detoured Avenue O between 106th and 126th streets. Truck traffic will be detoured  to Doty Avenue between 103rd and 130th streets.