Construction crews working the One World Trade Center site reached a milestone on Aug. 12 by placing the largest steel column to date for the $3.1-billion tower in Lower Manhattan. The 60-ft, 70-ton beam will serve as one of 24 perimeter columns that surround the building’s core. Once placed, the columns will allow the initial floors of the tower––including the lobby––to be built out. Tishman Construction is managing construction on the 2.6-million-sq-ft, 102-story structure for the Port Authority of New York and New Jersey. Construction began in April 2006 on the steel-frame tower designed by the New York office of Skidmore, Owings & Merrill. As of last month, the superstructure had risen 105 ft above grade. More than 2,300 tons of steel have been erected and Collavino Construction Corp. of New York has placed more than 33,000 cu yd of concrete.