Foundations are underway at 1448 Third Avenue, the site of a 39-story mixed-use tower in the Yorkville section of Manhattan’s Upper East Side. Designed by CetraRuddy Architecture and developed by Douglaston Development, the 478-foot-tall structure will span 287,632 square feet and yield 125 condominium units with an average scope of 1,804 square feet. The building will also contain 40,864 square feet of commercial space, 21,224 square feet of community facility space, a cellar level, and a 20-foot-long rear yard. The property is alternately addressed as 170 East 83rd Street and located at the corner of Third Avenue and East 82nd Street.