The Louisville Metro Public Works Department is giving a highly-visible feature of City Hall a makeover Thursday with a new exterior stair tower that will replace the old fire escape.Costing about $400,000, the steel construction is expected to be completed by early next year. But city officials promise the project upgrades will maintain the structure's historical look of the emergency escape, which was built during the 1940s.From the mayor's office: The tower will consist of four large steel columns with a steel cap reminiscent of City Hall’s cornice. It will also reflect details of the historic building’s limestone architecture and features decorative glass panels. The stair tower will be completely freestanding, with landings projecting to the building’s edge. The central tower will be painted to match the building’s limestone while the staircase will be painted to match its historic wrought iron. It was designed by Metro Public Works, Sullivan & Cozart and Studio Kremer Architects to meet current codes while incorporating historic landmark requirements. The project also includes replacing the sidewalk and curb at the corner of 6th Street and Congress Alley.The only bad side is that the construction will close the west side of 6th Street to traffic until work is completed, which will force local media crews to find alternative parking.