All work of designing, constructing, reconstructing, altering, relocating, or repairing of bridges shall be done by the Department of Transportation. All such work may be done either by contract or by forces employed directly by the City. City Code, 1879, art. 47, §79 1893, art. 48, §80 1927, art. 45, §146 1950, art. 35, §71 1966, art. 26, §7 1976/83, art. 26, §10 Ord. 1863-006 Ord. 48-520 Ord. 76-139 Ord. 15-435